[speaker004:] OK.
[speaker003:] OK. We can start?
[speaker004:] OK.
[speaker003:] OK. So, welcome to our next meeting. Uh, today we will have a talk from Miguel Sanchez [pause] concerning his [pause] uh [pause] work related to ad hoc networks. We have here a guest, a former [pause] ICSI member of the NSA group, Jordi Domingo Pasqual. He is, uh, assistant professor at UPC. And maybe Jordi, you have a few words [pause] concerning your work [disfmarker] one or two sentence and [pause] because we will have tomorrow a talk from him in more detail concerning what's going on.
[speaker005:] Eh, you [disfmarker] you want me to [pause] say [disfmarker]
[speaker003:] Yeah, only a short introduction,
[speaker005:] Oh!
[speaker003:] ve very short introduction, please.
[speaker005:] Of course. Eh, [pause] well, I'm working in the em [pause] Broadband Commu
[speaker003:] Uh, sorry, one interruption. This is not related to hearing, it's only for [pause] fixing it. It's not a earphone.
[speaker005:] Ah, it's not a hear [disfmarker]
[speaker003:] No. So.
[speaker005:] It works [pause] like [disfmarker] like this.
[speaker003:] Yeah, yeah. Like this one. Yeah.
[speaker005:] Ah,
[speaker003:] It's only a microphone.
[speaker005:] that's [disfmarker] Ah,
[speaker003:] Yeah?
[speaker005:] that's uh [pause] much more comfortable.
[speaker003:] OK. Yeah. OK.
[speaker005:] Thank [vocalsound] thank you. I'm uh [pause] working in the Broadband Communications Group and eh, eh well, the research topics at this moment is uh, [pause] I P eighty traffic monitoring and characterization and em [pause] eh [pause] tool [disfmarker] developing tools uh for quality of service, eh [pause] performance analysis. That's eh [disfmarker] [pause] And we have several projects eh [pause] both Spanish and European projects, ongoing eh [pause] in this area.
[speaker003:] OK. Thank you. And after the talk of [pause] uh, Miguel, I [pause] will [pause] give [pause] you [pause] all [pause] a few slides concerning the project proposal. I will um [pause] say something about in which direction it will go and uh Maybe it was my fault that I assumed that the pointer of [pause] Miguel [pause] concerning UMTS services was [pause] deployed to everybody, but it was only sent to me, so in the meantime everybody got, I believe, this pointer from me, and maybe we [disfmarker] It's a homework, in principle, for the next meeting, to get [vocalsound] [pause] a little bit familiar with these things.
[speaker001:] Worse than no work.
[speaker003:] And [pause] um so I believe we will not have [pause] today a very hard technical discussion, maybe more a few topic and items we will focus in the next days, until the next meeting. And when we are ready with our meeting. Everything is done. Then, uh, we have to read these number and we go around here, every member.
[speaker002:] OK.
[speaker003:] So.
[speaker004:] OK.
[speaker003:] Miguel, please.
[speaker004:] Thank you. Well, eh, I [disfmarker] I have [pause] prepared, eh, a really short talk about some of the topics I [disfmarker] I have been doing some w some research work [pause] uh before coming here. And eh, well, mainly I will present uh [disfmarker] [pause] Here you have more or less the sketch of the presentation. I will present some ideas and some concepts about [pause] what ad hoc networks are, about the issues in media access control in wireless networks, also about routing in such kind of networks and, eh, I will make some comments also about [pause] uh [pause] the current standards of wireless local area networks and finally, I will present the blueprint of [disfmarker] of my research project or my research uh proposal here. So [pause] the first thing is eh what an ad hoc network is. You know, uh, an ad hoc network is made of wireless nodes. These nodes of course can [pause] be mobile nodes, and, eh in this network there is no [pause] network [pause] infrastructure. So [pause] eh [pause] the only [pause] active thing we have is the mobile nodes. And eh end to end communication, is sometimes, uh [pause] [vocalsound] done by direct communication from one node to the other, because [pause] they can talk to each other. But sometimes it is not possible, this direct communication, because nodes, end [disfmarker] uh source or [disfmarker] and destination nodes are um are too far away. And in this case, [pause] it can be done, communication can be done, by uh using multi hub routing. So an intermediate, or a set of intermediate nodes will [pause] route or will forward the packet from the sender to the destination. So uh [pause] in a sense, what we have in this kind of networks, [pause] is that, uh [pause] nodes are as both arced as both uh [pause] endpoints and also routers of other neighboring nodes. And this makes a uh difference from [pause] other kind of network. And well, regarding [pause] the purposes of [pause] what can this kind of network be used for, [vocalsound] eh [pause] we can say that, well, cellular networks are infrastructure based networks, in this kind of ad hoc networks, we don't have [vocalsound] anything uh, with the exception of the network nodes. So, this uh network can be useful for eh [vocalsound] uh [pause] occasions where no available infrastructure is present, like for example, in [disfmarker] in [disfmarker] eh after some kind of [disfmarker] of [disfmarker] eh um [pause] catastrophe catastrophic event, or, also when [disfmarker] even when there is a network available, [pause] we don't want, for different reasons, to use the available network. This latt later case can be, for example, the use in military systems, where [pause] maybe we don't want to use the other [disfmarker] the enemy network infrastructure, for evident reasons. Yeah.
[speaker003:] Hmm? But you can also, I believe, uh to have an ad hoc network, where one node is then connecting to the outer world. For instance, what I have in mind, you have a car, where you plug in different devices and they talk to each other, for instance, but one device decided to go to the G S M network or GPS network, or whatever kind of things.
[speaker004:] That's OK.
[speaker003:] So there's a certain kind of task uh, for one node within the ad hoc network to provide connectivity to the outer world, right?
[speaker004:] That's O K.
[speaker003:] OK.
[speaker004:] That's perfect, you know.
[speaker003:] Yeah.
[speaker004:] This [disfmarker] in this case, we will say that this node is acting as a [disfmarker] as a gat external gateway, from this network [pause] to connect to other networks,
[speaker003:] Right.
[speaker004:] and of course the underlying [pause] uh protocols can can be, of course, uh IP based. Uh, OK. Here you have several [disfmarker] several uh, proposed, uh, scenarios for [disfmarker] for used this networks. When no network is available, OK? And another [disfmarker] another application, for example, NASA is [disfmarker] is uh studying, is uh the use of these networks, these ad hoc networks, for sending multiple probes, uh, um [pause] uh [pause] missions. So, for example, all of you are aware of this uh [disfmarker] the last Atlas, the last successful uh Mars mission, the cellular vehicle was only one, and was uh walking around, uh roaming around the base station, which in this case was the gateway uh node of this network, but it was only one mobile node, of course. Nothing prevents, except well maybe the cost, to send not only one mobile rover, but ten tons of them, or [disfmarker] [pause] or at least uh several of them. So, [pause] uh higher area could be covered, could be explored and uh of course, all the different nodes could also use some kind of ad hoc networking,, ad hoc routing, to extend the distance, the maximum distance, than uh a single radio transmission will [disfmarker] would allow. OK? And in the other case, or the other area uh of [disfmarker] of [disfmarker] of application, [pause] is the so called network of sensors, where [pause] we can deploy a set of sensors in a maybe uninhabited area, let's say, for example, the forest, and we can uh take some information uh, for example for [disfmarker] for fire fighting, we can just launch from a plane, several small sensors, and uh these sensors can be for example, uh checking that there is no fire, they can have some kind of uh let's say infrared technology sensor, so we can cover a huge area with only a small set of [disfmarker] of sensors, and without any other infrastructure. Yeah.
[speaker002:] Um, is that really an ad hoc network? Because the sensors are not moving. And I think it's [disfmarker] makes no sense with moving sensors because then you don't know where the sensors are.
[speaker004:] Yeah.
[speaker002:] So.
[speaker004:] Well, You know, it's an interesting question. Uh, the [disfmarker] the main thing about an ad hoc network is not that nodes move. It is the way of topology changes can happen. The idea that mmm, any change is possible at any given moment. But you can of course ask, "but if the nodes are not moving, what kind of topology changes can we expect?"
[speaker002:] Yeah. That's it.
[speaker004:] Well, eh, the thing is that usually in [disfmarker] in a n in a network of sensors, what we have, or the idea is to have um, an important number of sensors, and maybe with a high filer rate.
[speaker003:] Yeah.
[speaker004:] maybe the batteries are uh [pause] [vocalsound] exhausted in some nodes because maybe uh they are not being able to take uh, let's say, any sun to recharge its cells,
[speaker002:] OK. Mm hmm.
[speaker004:] uh maybe some of them can be uh just uh out of order [pause] for other [pause] eh environmenta environmental conditions. So uh the idea is that even when these nodes are not moving, they can start and stop working at uh, let's say, higher pace. Then, uh [pause] what will happen in a [disfmarker] in a regular network, uh in a network where you don't have or [disfmarker] either mobility or uh this uh on off uh rate, high rate.
[speaker003:] Mm hmm. Let me go back to your uh uh example.
[speaker002:] Hmm.
[speaker004:] Yeah.
[speaker003:] Have in mind some routers are burnt [pause] here, at ICSI or whatever kind of thing, what will happen then even in a fixed network?
[speaker002:] Mm hmm.
[speaker003:] So, if some sensors are getting out of uh [pause] service and whatever kind of thing, so the topology has changed, even if no node is moving.
[speaker002:] OK. Mm hmm,
[speaker003:] Yeah.
[speaker002:] OK.
[speaker003:] And how to provide the connectivity and the intercommunication things wi within this network.
[speaker004:] Thank you, Joe.
[speaker002:] Yeah, I see. Mm hmm.
[speaker004:] Well, uh, you know, and finally, uh, another non military applications, where uh maybe a network is available, like for example, a room like this, where we have, in fa in fact, a wired infrastructure, but [pause] this uh [pause] possible application of ad hoc networks could be uh, any place, any meeting room, where we arrive with our computers and eh we just [pause] can communicate seamlessly [pause] to each other without [pause] any kind [pause] of access point, any kind of uh mmm external network, because [pause] the kind of work we want to do is just only local based, it's only to chat to each other or to exchange files with the person, which is [pause] in front of us. OK, but we n don't want to product [disfmarker] pro provide, eh, access to the internet or something. OK? And, of course, the same eh [disfmarker] the same scenario, [pause] could also happen in a place where there is no [pause] uh, infrastructure available. Let's say a meeting room uh, in [disfmarker] in the middle of the desert, OK?, without any other network. So the point [disfmarker] or [disfmarker] or the question could be for some of us, the idea of saying "OK, That sounds OK, but why [pause] not to use a longer transmission range, so we can reach any destination in just one hop?" This seems to make sense because, [pause] well, uh we are [pause] this way avoiding all the routing problem that, well, we will talk a little bit uh, about routing [pause] later, but uh it [disfmarker] it seems that i probably that the problem is [disfmarker] is not an easy one, because uh a node's moving, the route is changing, so w one can think that routing in this uh scenario is [disfmarker] is a complex thing. But the problem is [pause] if w we just uh [pause] try to put more power in each tr transmitter, so this uh transmitter can reach any destination [pause] in only one hop, what we are doing is uh to rising the power needs of each node, and also we are reducing the network uh throughput, because we are only allowing one transmissio one transmission at a time. Because uh, well, we cannot allow several transmissions, several high powered transmissions at the same time because one is interfering with the other. OK? We are [disfmarker] uh I think I'm not telling [pause] it yet, but [pause] we are assuming [pause] that we are using a single common channel for all the nodes. OK? So that's why [pause] we cannot allow several transmitters in the same channel at the same time. OK? So, the idea of hav having a longer transmission range is not [pause] a good [pause] one. or at least it has the drawbacks um, um, I was telling you. Eh, let's speak a little bit about the media access issues in [disfmarker] in wireless networks, Uh, you know, the [vocalsound] easiest eh way to [disfmarker] to show how this works is [disfmarker] or at least one of [disfmarker] I think one of the easiest [disfmarker] is that this drawing, or this picture, what [disfmarker] what we have is a set of nodes, each one at a different location. At [disfmarker] at [disfmarker] at a [disfmarker] at an [disfmarker] at a given moment this eh node, this dash node is [disfmarker] is transmitting and [pause] uh, the arrows are representing this transmission and the receiving nodes, these three nodes, are receiving the transmission, and I'm trying to uh [pause] show the area, the covered area, for [disfmarker] of this transmission by means of this uh dashed eh line circle. OK? So, uh, any transmission [vocalsound] has a maximum transmission range, and uh in the [pause] simpler way, we can see this like a circle with the center in the transmitter and a certain radius. OK? The value of this radius is uh [disfmarker] [pause] in principle, is a fixed value and it depends on the uh power of the transmitter. Of course, uh [pause] this is only our uh [pause] simplife simplified model and of course this can be uh [pause] improved uh [pause] a lot, OK? And in fact the real behavior is not exactly this one, but uh for [disfmarker] for what I want to say it's [disfmarker] it's [disfmarker] OK, it's enough. OK? So what are the differences uh, in this [disfmarker] in this eh [pause] wireless transmission, regarding uh to the wireless [disfmarker] to the wired ones. What [disfmarker] what are the d the main differences. Well, the main differences come from the fact that, uh in uh [disfmarker] in uh wireless transmission we have a special domain we don't have when we are using a wire for transmitting a signal. And the point I'm trying to show in this picture, is that if for example, this other node wants also to transmit while this one was transmitting, if we are using some kind of carry detect scheme, like for example, CSMA, or something uh uh derivated from it, the problem is that this node will hear the g the m the transmission media, it won't be able to hear anything so, he will conclude that [pause] no other transmission is going on, and he will start transmitting. And if he does, what will happen is that this node and this other node will also receive this transmission, and this will produce, at least at these two nodes, a collision or a m a m a [disfmarker] a re a bad reception. OK? So none of these two simultaneous transmissions will be properly received at this node nor at this other node. OK, eh, this problem is what is called [disfmarker] Oh, sorry. uh, the [disfmarker] I think this is the previous one? This is the German [disfmarker]
[speaker003:] Uh.
[speaker001:] No. One
[speaker003:] Yes,
[speaker004:] OK,
[speaker003:] this one.
[speaker004:] thank you. Eh this is what is called a "hidden terminal" problem. OK? because well uh this node is not able to hear this other node [pause] because of the distance [pause] uh, between them. But Uh, this problem, as you can see in the [disfmarker] in the picture, is uh really producing [pause] at least some reception problem at these two nodes. OK, so it is [disfmarker] it is a problem that we have to address and it is a new problem compared to wired uh media access control. And, uh, well, some devel some protocols have been developed to avoid this problem and to try to address this particular behavior of wireless transmissions and the main idea is to use some kind of a reservation mechanism. So we are um reserving a certain, and a specific uh, area of space so we can [vocalsound] guarantee that nobody is trying to use the same space at the same time. OK? This is the basic idea.
[speaker003:] Mm hmm. Um
[speaker004:] Yeah?
[speaker003:] Miguel, can you give some examples for such kind of protocols?
[speaker004:] Yeah. Yeah, in fact [disfmarker]
[speaker003:] One is really [disfmarker] really [disfmarker]
[speaker004:] This one. This one, n next slide is [disfmarker]
[speaker003:] OK. Yeah, yeah. OK.
[speaker004:] OK, in eh the [disfmarker] the [disfmarker] the main idea and [disfmarker] and the base of most of this protocols, is what this [disfmarker] the so called RTS CTS uh dialogue. The idea is that, uh, of course, this is only intended for unicast transmissions, I mean, only for when a node wants to transmit something to a neighbor node. OK? But not to broadcast. Uh, to all the nodes. OK. For this [disfmarker] for this eh, work, the transmitter has to send a [disfmarker] a [disfmarker] a reservation packet called RTS, "Request To Send", before eh [pause] being able to send data. And the receiver is expected to return back another packet [pause] called CTS, "Clear To Send", to allow the transmitter to send the data. If the transmitter receives successfully the CTS packet from the destination, then it will be able to send eh the packet, the data packet. If not, it will h uh, back off, and it will retry uh sometime later. OK? So the main idea [disfmarker]
[speaker003:] And the media is [disfmarker] is [disfmarker] is still occupied during that period, or [disfmarker]?
[speaker004:] Uh. Yes. Yes.
[speaker003:] OK.
[speaker004:] The idea is uh, if I want to send you something, I [disfmarker] first of all, I need you to answer me to be sure that you are my neighbor now because maybe you are off or maybe you are uh too far away, and also because that way Miguel, for example, it may be is not being able to hearing me will hear your CTS and will know that you are about to receive uh data from me. OK? So in fact, forcing the receiver to transmit for a short period of time is also uh, used to signal all the uh receiver neighbors that a recept a reception is taking place. OK?
[speaker003:] Yeah. I didn't get it. Um, what happened when I sent an RTS packet? Is then the media still occupied for me? Or, is anybody allowed also to send RTS packets?
[speaker004:] Or everybody [disfmarker]
[speaker003:] Because if I go to an intermediate node, maybe you are communicating to me and I am the intermediate node to the final destination Michael. And Michael send also some RTS packet in the time and [disfmarker] and [disfmarker] uh uh uh Jordi too and whatever.
[speaker004:] Yeah.
[speaker003:] Then you will never come to a really [disfmarker] then you're always exchanging RTS and non acknowledgement packets for the RTS.
[speaker004:] OK. Two [disfmarker] two things.
[speaker003:] So that's uh [disfmarker] that's uh, my [disfmarker] my problem.
[speaker004:] First of all, [pause] eh, this [disfmarker] this mechanism is only a media access controlled mechanism, so it is not connected [pause] with routing [pause] eh, anyhow.
[speaker003:] Then, fine.
[speaker004:] And, second point,
[speaker003:] OK.
[speaker004:] eh
[speaker003:] So it's only related to the direct neighbor within the scope of the [pause] transmissions?
[speaker004:] RTS [disfmarker] Yeah, RTS packets can collide [pause] to [pause] other RTS packets.
[speaker003:] OK.
[speaker004:] So, [pause] this mechanism [pause] is not [pause] uh preventing [pause] collisions, it is preventing only data collisions. OK?
[speaker003:] OK.
[speaker004:] So the [disfmarker] And [disfmarker] and [disfmarker] you can say "OK, but what is the [disfmarker] what the benefit is?" The benefit is that, eh RTS packets and CTS packets are short packets, really short packets. Let's say eh [pause] eh 30 bytes or less.
[speaker003:] I assume so. Yeah.
[speaker004:] while data packets can be much mor much bigger. Let's say uh one K, five K s. OK?
[speaker003:] Yeah.
[speaker004:] So
[speaker003:] Fine.
[speaker004:] a collision in this short packet [pause] is only wasting a small amount of time. And, uh if that way we can warranty that there is [disfmarker] there are [disfmarker] there is no collision uh uh, between data packet, well, this [disfmarker] this is [disfmarker] this means a [disfmarker] a huge eh increase in network throughput, because we well, we [disfmarker] we only waste really small time colliding.
[speaker003:] OK,
[speaker004:] OK?
[speaker003:] but that means, in principle, that on the MAC layer you have always a RTS CTS [pause] packet between neighboring nodes,
[speaker004:] Yeah.
[speaker003:] and you send afterwards the data. But the data will be maybe delayed in the [pause] intermediate node because you have always be assured to be uh s uh uh RTS and CTS packets are changed before [disfmarker] [vocalsound] before you can forewarning the data, right?
[speaker004:] Yeah. It is a reservation mechanism,
[speaker003:] Yeah. OK.
[speaker004:] so if reservation [pause] doesn't work OK, if uh one reservation don't succeed then, uh, this transmission should have to wait.
[speaker003:] Now the p
[speaker004:] until the reservation [disfmarker] OK, yeah, let me [disfmarker]
[speaker003:] Maybe it's better to [disfmarker] to uh, [pause] draw it on the [disfmarker] Oops.
[speaker004:] l let me [disfmarker]
[speaker003:] So, maybe my idea first. So this is what, node one? This is node two and this is the source,
[speaker004:] Yeah.
[speaker003:] and this is node three that is the final destination.
[speaker004:] Yeah. Fo fo for forget [disfmarker] forget about routing.
[speaker003:] Yeah? Yeah, yeah. OK. But but anyway, I would like to do that in the ad hoc network. This is maybe the sco this is within the scope [pause] of this, uh [pause] special network. That means here that is uh within the transmission power.
[speaker004:] OK.
[speaker003:] So if I send [pause] an RTS, and get back, [pause] um, a CTS, then he is allowed to send data, right?
[speaker004:] Mm hmm. a CTS. That's OK.
[speaker003:] So. In the meantime, when he gets this one, he also had to send RTS [nonvocalsound] and then CTS because this is the next next scope of the transmission area,
[speaker004:] Mm hmm.
[speaker003:] and then he can send the data, right?
[speaker004:] OK.
[speaker003:] That's the case?
[speaker004:] That's it. That's [disfmarker]
[speaker003:] Yeah? And that's what I mean. In the meantime, he c still can get some data here, where he try to get certain connectivity on the MAC layer.
[speaker004:] Mm hmm. Yeah, but eh [pause] a node is only [disfmarker] is only involved in one transmission at a given time. So if now two has uh mmm answer with the [disfmarker] with the CTS, it will be waiting until the data that has to come.
[speaker003:] Yeah? OK,
[speaker004:] OK?
[speaker003:] and then he try to forward this data.
[speaker004:] Yeah.
[speaker003:] After that.
[speaker004:] But n not before.
[speaker003:] So he is definitely first to stop. He has to collect all the data?
[speaker004:] Yeah. Yeah, you cannot [disfmarker]
[speaker003:] Could it not be a little bit strange because if that is starting a file transfer with millions of bytes, he have to collect all the bytes before he forwarding to [disfmarker] to whatever.
[speaker004:] No, no, no. But [disfmarker] we are [disfmarker] we are talking only about a data packet.
[speaker003:] Huh? One data p
[speaker004:] at the MAC layer.
[speaker003:] He have to do it for all data packets?
[speaker004:] Yeah.
[speaker003:] OK. OK. So but, in principle, [pause] when he receives the data packet then he [disfmarker] The same applies for the next data packet.
[speaker004:] Yeah. All the packets, all unicast packets.
[speaker003:] but anyway in the meantime he has to forward the packet to the final destination.
[speaker004:] Yeah. That [disfmarker] that true.
[speaker003:] Right?
[speaker004:] That's true.
[speaker003:] So it's acting, in [disfmarker] in prin
[speaker004:] But not in the meantime. After receiving [disfmarker] You know, in fact, probably the routing protocol [pause] will need to check the address [disfmarker] the [disfmarker] the let's say IP address, which is inside the data packet,
[speaker003:] OK. Yeah.
[speaker004:] so, you cannot [disfmarker] u usually you cannot, uh, read the data packet until you [disfmarker] [pause] the reception is over. OK? because [pause] usually your network hardware only provides you a copy of a packet after ou a [disfmarker] a successful reception and usually you know that reception is successful if every bit has passed the CRC check. OK? You have checked that the [disfmarker] that this frame has received [pause] uh without errors.
[speaker003:] Naja to [disfmarker] to [disfmarker] Yeah.
[speaker004:] OK?
[speaker003:] Mm hmm. Yeah, [@ @]. OK.
[speaker004:] So
[speaker002:] Um, a further question.
[speaker004:] Yeah.
[speaker002:] Um.
[speaker004:] That's OK.
[speaker002:] Am I right that this um dialogue does not prevent um any disturbance of other nodes in the um sending range of, yeah, N one.
[speaker004:] Yeah, let me [disfmarker] let me put some special representation of what we are doing.
[speaker002:] S
[speaker004:] OK. This is the transmitting [pause] node, this is the receiving [pause] node, and these two areas, of course, there's something like this, are the uh places of the [pause] total space where you can hear the [disfmarker] Here, this one is the RTS and this one is the CTS.
[speaker002:] Mm hmm.
[speaker004:] So, any node, for example, this node [pause] is a neighbor of the receiving node,
[speaker002:] Mm hmm.
[speaker004:] but it is not a neighbor of the transmitting node.
[speaker002:] Yeah. That's it.
[speaker004:] So when this node hears the CTS transmission that is performed by the receiver, this will be uh [pause] informed, that a recev a reception is taking place in [disfmarker] in [disfmarker] in it's area.
[speaker002:] Mm hmm. Mm hmm.
[speaker004:] OK? So in fact, this node will avoid any further transmission until uh this reception, that will start in [disfmarker] in a moment, is over.
[speaker002:] But then this node, um, this transmission is uh aborted.
[speaker004:] OK?
[speaker003:] And delayed.
[speaker002:] And so there's no advantage to uh [disfmarker] if it's aborted, by [disfmarker] by any data packets.
[speaker003:] Yeah.
[speaker002:] So this um node has to stop each transmission.
[speaker004:] Yeah.
[speaker002:] So, even the at the moment ongoing transmission.
[speaker004:] Mm hmm.
[speaker002:] Is that right?
[speaker004:] Yeah.
[speaker002:] So, his transmission is aborted.
[speaker003:] Yeah, but this is typical for MAC layer protocols, you know.
[speaker004:] Not [disfmarker] No. No.
[speaker003:] That's [disfmarker]
[speaker004:] Let me [disfmarker] let me [disfmarker] let me [disfmarker] show you one thing. If this node was transmitting before, it should uh it should ha uh [pause] transmit an RTS packet in advance, OK?
[speaker002:] Mm hmm. Mm hmm.
[speaker004:] So this node should hear it before.
[speaker002:] Yeah.
[speaker003:] Yeah.
[speaker002:] That's right.
[speaker003:] Yeah.
[speaker002:] Mm hmm.
[speaker004:] So this node [pause] is [disfmarker] W won't be sending the eh eh CTS packet to the transmitter.
[speaker002:] OK. Yeah.
[speaker003:] Yeah.
[speaker002:] Mm hmm.
[speaker004:] So this transmission [pause] won't take place.
[speaker002:] OK, yeah.
[speaker003:] Yeah. It's always true that only [pause] one node gets a media access, for one frame.
[speaker002:] Mm hmm. Mm hmm.
[speaker003:] That's the point.
[speaker004:] M Yeah.
[speaker003:] We always said "from data" but it's really one frame.
[speaker004:] Yeah.
[speaker003:] Yeah, OK.
[speaker004:] And, in fact, uh there is another detail, it is not uh uh uh uh in [disfmarker] on the [disfmarker] on the slide, and it is that both the RTS and the [pause] CTS packet uh, have a [pause] field, a control field where [pause] the [pause] total length of the data packet is shown.
[speaker002:] Mm hmm.
[speaker004:] So when you hear one uh CTS or one uh RTS packet, you know that the frame that they are trying to transmit [disfmarker] or, that this one is trying to transmit this one [pause] is about to receive [disfmarker] You know the length. You know the bit rate,
[speaker002:] Mm hmm.
[speaker004:] so you know that the amount of time you have to wait until you can try to get the control, or t try to send your own transmission.
[speaker002:] Mm hmm. OK, but this scenario is also nov uh, only working if um both or all nodes have the same range of transmission. So, the s same radius of the sending range.
[speaker004:] Mmm, yeah.
[speaker002:] So otherwise um this one node maybe [pause] um [pause] would hear [pause] his neighbor but not vice versa.
[speaker004:] Uh, well, we are assuming that uh mmm all the [disfmarker] all the transmissions are bidirectional. I mean, uh you know it depends. It depends mainly on [disfmarker] on [pause] the antenna gain and the transmission power and the receiver uh [pause] threshold.
[speaker002:] Mm hmm. Mm hmm.
[speaker004:] OK?
[speaker003:] Uh huh.
[speaker002:] But I'm thinking about this example you gave [pause] before.
[speaker003:] Maybe [disfmarker] maybe you are right.
[speaker004:] S So what [disfmarker] what we are assuming is that all the nodes behave exactly the same regarding to uh transmission and receiving signals.
[speaker003:] Yeah, but, Miguel, this is a good point from [disfmarker] from Dietmar,
[speaker002:] Yeah.
[speaker003:] but maybe here is a wall. And this guy is behind the wall, so [pause] his transmission rate is something like that.
[speaker004:] Yeah but [disfmarker] but [disfmarker] yeah but the [disfmarker] but in this case, you know this [disfmarker] this idea, this uh geometric idea, can be [disfmarker] can be, if you want, uh deformed because of some obstacles. OK? But this wall is working both ways. It is not only making this node not to hear this one, it's also making this one not to hear this node.
[speaker002:] But one of the [disfmarker]
[speaker004:] So if they [disfmarker] Because of this wall, if they are not neighbors, well, we can represent this putting this node like here.
[speaker002:] But one of the um senders could be much stronger than the other one.
[speaker004:] OK? No, but this is not the scenario we are assuming.
[speaker002:] So [disfmarker] OK. So that was my question.
[speaker004:] Yeah.
[speaker003:] Mm hmm. OK.
[speaker004:] We are assuming all the nodes are exactly the same.
[speaker002:] OK.
[speaker004:] Uh, so they transmit the same power, and they uh have the same uh uh sensitivity.
[speaker002:] Mm hmm.
[speaker004:] So they can hear [disfmarker]
[speaker002:] OK.
[speaker004:] If [disfmarker] if [disfmarker] if I can hear you, you can hear me.
[speaker002:] Mm hmm.
[speaker004:] and [disfmarker] and the opposite works also.
[speaker002:] Mm hmm.
[speaker004:] OK, if you cannot hear me, I cannot hear you.
[speaker002:] But [disfmarker] Mm hmm. OK. It's a assumption it's [disfmarker] it's clear. But on the other hand, um, in a real world it isn't, or [disfmarker]? Um.
[speaker004:] In a?
[speaker002:] In real scenarios, uh, you have to [disfmarker]
[speaker001:] It [disfmarker] It is actually [disfmarker]
[speaker004:] Uh [pause] not really, but also depends on uh you know, for example power relationships, and antenna relationships.
[speaker002:] Yeah,
[speaker004:] You know, eh
[speaker002:] eh that's it.
[speaker004:] Because [disfmarker]
[speaker002:] A car or [disfmarker]
[speaker004:] because for example, uh [pause] one kind of thing, OK, if I use a directional antenna, this is making that in one direction,
[speaker002:] Yeah. Mm hmm.
[speaker004:] I'm getting more uh [pause] let's say more gain than another.
[speaker002:] Yeah,
[speaker004:] And that's true
[speaker002:] OK.
[speaker004:] but th that [disfmarker] What is also true [pause] is that one directional antenna works both ways.
[speaker002:] That [disfmarker] You're not assuming this. Yeah.
[speaker004:] It provides you [pause] more gain [pause] when you are transmitting but also when you are receiving. so, in general, in general even when [disfmarker] if there [disfmarker] uh [pause] if there i are different antenna gains, uh, you're getting mainly bidirectional channels. Only when you have a an important uh power difference is when l um, the communication can only work one way.
[speaker002:] Yeah. OK.
[speaker004:] For example, you have one big station with uh [vocalsound] a lot of transmission power, and then you have a really small mobile uh thing that can hear perfectly the signal from this uh uh bigger station,
[speaker002:] Yeah. Yeah, a cellular phone and a car.
[speaker004:] but it has not enough power to transmit something that can be heard here.
[speaker002:] Mm hmm. Yeah.
[speaker004:] So um [pause] But this [disfmarker] this [disfmarker] this is not our scenario.
[speaker002:] OK.
[speaker004:] In our scenario, all the nodes are exactly the same.
[speaker002:] Mm hmm. OK.
[speaker004:] They [disfmarker] they have the same uh signal uh behavior.
[speaker002:] Mm hmm.
[speaker004:] So this is not a problem for us, at least for the moment, maybe later we'll see some differences. So You know, the idea is that this mechanism is a reservation mechanism. And what we are doing here is try to reserve the area of space we are covering and eh here's where our [pause] some of our work [pause] is done. The main idea [pause] for [disfmarker] for our work, is well, [pause] if we are using this reservation mechanism, we are reserving an area of space for a single transmission. Uh, if this area is bigger than what is really needed, we are, somehow, wasting a little bit of space. So, uh our first eh work in this area [pause] was [pause] to study different mechanisms [pause] to try to adjust [pause] these transmission values, these uh the area, the covered area, [pause] for a single transmission, trying to get a minimum value, so [pause] we can [pause] reduce [pause] the not used space for other simultaneous transmissions. And this will [pause] lead us to a [disfmarker] a better [disfmarker] [pause] to a better network throughput, to higher number of simultaneous transmissions. And, we have, uh mmm, worked about this problem [pause] uh, in two different uh ways. One of these ways has been [pause] try to find a mechanism [pause] to uh calculate [pause] an optimal value [pause] for the transmission range [pause] uh, and to get [pause] an equal value for all the transmitters. So, [pause] the idea in this first work [pause] was [pause] to obtain [pause] a fixed value [pause] for the transmission range. And the second eh work, uh, it is about [disfmarker] Oops! It is about uh, an algorithm to adapt the transmission power for every for every single transmission. So, uh, in this second part of our work, [pause] we are using a different value for every single transmission. So. First point, [pause] what we have proposed is [pause] a way [pause] to obtain [pause] the transmission [pause] range [pause] uh [pause] for uh for an escenario where we know the number of nodes and the area of deployment, [pause] we have a [disfmarker] a fixed area, where we deploy all the nodes, we have a fixed number of nodes, and, [pause] uh we assume that these nodes are moving [pause] freely around this [disfmarker] this area and, uh, what we have presented, [pause] is a mechanism [pause] to uh calculate [pause] to obtain [pause] the eh [pause] transmission [pause] radius that [pause] provides at the same time [disfmarker] that provide us [pause] the better throughput possible [disfmarker] the better possible throughput, OK? but without our network getting partitioned, which is a problem that we are trying to avoid. You know, if we have, because of node motion, we have something like this, this is the deployment area of [disfmarker] or [disfmarker] or node, and if we have some nodes here and some nodes here, [pause] well maybe these nodes in this area, cannot reach the nodes on this other area. OK? Uh, so [pause] what can we do to avoid this? Of course we can choose uh our transmission values longer enough to reach from [pause] so the nodes from this area will be able to reach the nodes on this other area. OK? But, again, we can assume that eh if uh, nodes are moving, [pause] uh [pause] more or less uh [pause] in a random fashion, this configuration is not very likely to happen. OK? So [pause] the point we ha what we have done [pause] is to present a mechanism would pr which provides [pause] uh [pause] one uh [pause] value for a given uh [pause] mmm [pause] probability. OK? So we can say that uh [pause] a given eh value are [pause] [@ @] for [disfmarker] for the transmission range, will be OK for a given number of nodes, if [pause] we [disfmarker] Sorry. for a certain, for a certain probability. OK? So, the point is uh, we cannot say that this is not gonna happen, what we can say is this is not very likely to happen, [pause] if nodes move uh uh random.
[speaker003:] Yeah, but um Miguel, [pause] if uh in the previous slide you mentioned that you uh are working also on adaptive power control.
[speaker004:] OK? Yeah. Yeah.
[speaker003:] Is it not possible then, if I send something and I could not find any neighbor because one of the cluster below,
[speaker004:] This is the next. Yeah, th
[speaker003:] is it not possible to extend the power until the maximum
[speaker004:] u
[speaker003:] and if uh I do not have any connectivity with the maximum of power, OK, then I'm lost anyway.
[speaker004:] e e Yeah,
[speaker003:] Yeah, yeah.
[speaker004:] but [disfmarker] this is [disfmarker] this is a way that it is [disfmarker] it is being explored by other researchers, but not [disfmarker] not uh, by me. But uh, there is, uh [pause] one, at least one person who is [disfmarker] who is doing what they call "topology control",
[speaker003:] Mm hmm.
[speaker004:] and this is, uh [pause] related to [disfmarker] to uh the control of the transmission power to get uh [pause] certain properties uh from your network, like for example, they are [disfmarker] what they are doing eh is eh some people working for BBN Ram Ramanatan is the researcher,
[speaker003:] Mm hmm.
[speaker004:] and the article is [disfmarker] is uh I think from [disfmarker] from this year, and eh these guys are doing eh what they call uh "B connected networks", they are trying all the network nodes to have at least two neighbors.
[speaker003:] OK, mm hmm.
[speaker004:] OK? And they are controlling the power to eh this g uh mmm get this [disfmarker] [pause] this number of neighbors, but this is not what I am doing and uh the kind of power control I am doing uh, um, is more or less [pause] presented here, and what we are doing is to transmit uh [pause] with the minimum power needed depending on the distance to the destination. OK? Every transmission is supposed to be done to a certain neighbor node we cull the neighbors to these nodes which are [pause] uh closer than a given distance, OK? and because we wanted to [disfmarker] to compare our algorithm with something, we needed to compare it with the no power control, which is the usual uh mechanism at this eh media access control level. So, what we are doing here is to [disfmarker] to compare our mechanism against the no power control, but again we have to fix [disfmarker] in order to be able to compare, we have to fix a given whatever, but a given uh maximum transmission range to compare. And, uh [pause] what we are doing is [pause] we are uh [pause] taking the advantage that we are u we have this RTS CTS dialogue, in advance, before sending the data, to uh [pause] agree with the receiver, the power level he is willing to get from us. OK, so every single transmission [disfmarker] in every single transmission we are checking with the receiver the power level we have to use for the data transmission. That's the main thing. And [disfmarker] as, uh [disfmarker]
[speaker003:] And how do you [disfmarker] sorry Miguel [disfmarker] how do you check if [disfmarker] if the nodes are moving randomly?
[speaker004:] Well, uh we are assuming that e y for [disfmarker] at least for uh [pause] veh uh you know, uh, car and [disfmarker] and walking or [disfmarker] or people riding a mo motorcycle the f um frame length is so small that only um [pause] very [disfmarker] very small um [pause] space can be [disfmarker] can be eh travelled while the transmission is taking place. You know, in one millisec
[speaker003:] Yeah, OK, maybe that's applied for RTS CTS, but for the real frame?
[speaker004:] Yeah, well, you just take the [disfmarker]
[speaker003:] The frame could also be uh whatever, [pause] I don't know but [pause] a few hundred bytes, you know, that takes a little bit time.
[speaker004:] Let's [disfmarker] let's [disfmarker] no but [disfmarker] Yeah but, i let's say you have one kilobyte. OK? One kilobyte is uh [pause] eight uh bits. OK?
[speaker003:] Mm hmm.
[speaker004:] And eh, if you are transmitting at, let's say, uh at one megabit per second, this means one microsecond per bit. OK? So this only is taking eight milliseconds, which is not a lot of time if you are travelling, let's say, at uh one hundred kilometers per second.
[speaker003:] No, s
[speaker004:] Oh per [disfmarker] per hour.
[speaker003:] no sorry m Yeah, that's right.
[speaker004:] Sorry.
[speaker003:] But first of all it took place RTS CTS, and there could be, you mentioned, if it's still occu if the medium is still occupied by another one, it will be delayed anyway to a randomly time.
[speaker004:] Yeah, it will be delayed but you will start from scratch again. I mean, it will be a start with another RTS CTS.
[speaker003:] Oh, so! OK, y OK. OK. I see. Yeah. OK.
[speaker004:] OK? But, anyway, [pause] uh, well, depending on [disfmarker] on the network, you now, the [disfmarker] the [disfmarker] the [disfmarker] this [disfmarker] I will have to translate this, uh It shou should be something [pause] ipsh So, this should be something like uh thirty meters per second. OK?
[speaker003:] Oh yeah, something like that.
[speaker004:] So in [disfmarker] in eight milliseconds, well, the amount of [disfmarker] of space you are travelling is not too much.
[speaker003:] It's OK.
[speaker004:] For most of [disfmarker] of [disfmarker] of uh [pause] the wireless technologies, maybe not for all of them, OK, but [disfmarker] I'm [disfmarker] [pause] of course, I'm also uh using a conservative value for the transmission speed, now you can get much more speed than [disfmarker] speedier interfaces than this one, but [disfmarker] the thing is, uh, that we are assuming that for a given transmission, we can uh [pause] consider the network as if it were built of a set of static nodes. OK? Motion will be important for routing, but for the media access control level, we are considering that motion can be con [pause] is not [disfmarker] is not important. OK?
[speaker003:] Yeah, what I think [disfmarker] Maybe some, uh [pause] cases why I go this way with my node, and suddenly, I s go out of the scope of the transmission area, because it's really a random movement. Then I still hear [disfmarker] this is during the data transmission.
[speaker004:] Yeah, but [disfmarker] again [disfmarker] again, what we are adding with this behavior is, uh [pause] uh [pause] a little bit more, probably some [disfmarker] some uh small part to the uh bit error rate.
[speaker003:] Yeah? then [disfmarker]
[speaker004:] OK? Maybe this frame will [disfmarker] won't be received properly, and, should eh [pause] have to be eh dropped,
[speaker003:] Oh, yeah.
[speaker004:] but anyway, eh [pause] even if nodes are completely static, eh some problems will happen [pause] in the wireless transmission, so we won't have a hundred percent eh perfect eh channel anyway.
[speaker003:] Yep. Right.
[speaker004:] So eh [pause] if this problem, as you show it [pause] probably it's [disfmarker] it's eh [disfmarker] [pause] Y you can [disfmarker] you can see that it is not very likely to happen, because [pause] you [disfmarker] you [disfmarker] you eh have to consider the probability that o of happening this [disfmarker]
[speaker003:] Nee. That's really right,
[speaker004:] Hmm?
[speaker003:] but what I would like to say is that besides the RTS CTS behavior, you need certain kind of additional MAC layer functionality to deal with these packet.
[speaker004:] Hmm hmm hmm.
[speaker003:] For example, with transmission or [disfmarker] or whatever,
[speaker004:] Yeah, sure, sure.
[speaker003:] for whatever control, or whatever kind of things, you know.
[speaker004:] In fact [disfmarker] in fact, you know I [disfmarker] I [disfmarker] I [disfmarker] I [disfmarker] I [pause] maybe I [disfmarker] I [disfmarker] I [disfmarker] had to [disfmarker] to prepare a more detailed eh, view, I [disfmarker] I just was trying to do something soft, not to [disfmarker] to bore th the public but of course there are a lot of other smart eh things that are built in, in these protocols,
[speaker003:] Right. Yeah.
[speaker004:] like for example, an automatic, uh [pause] acknowledgement. Some protocols used uh [pause] in the same way as this RTS and CTS packet [disfmarker] some of them use, an eh acknowledge from the receiver, which is also a short packet, so you [disfmarker] you are getting some kind of link layer uh [pause] acknowledgement scheme which can save a lot of data transmissions because eh usually when you send a [disfmarker] [pause] a [disfmarker] a [disfmarker] a frame, you will want to [disfmarker] some kind of acknowledgement back. So, if this acknowledgement has to go through the process of a new RTS and a new CTS, well, this takes longer than just a link layer uh, extra packet. That, of course uh [pause] is also contemplated in this eh packet length [disfmarker] length or [disfmarker] included in the RTS and CTS packets, so, eh, you know, everybody can wait until this uh acknowledgement is also transmitted by the receiver. So in fact, eh nnn [pause] some people proposing this mechanism is [disfmarker] is showing a [disfmarker] a b a big improvement and eh there are a lot of other mechanisms, also regarding and a time out mechanism, or the time out algorithm for these retries when you [pause] try to send something [pause] and you don't succeed, uh, what [disfmarker] what you the amount of time you have to wait until you retry again. Well, uh, some people is also proposing different things, different eh algorithms with different results. So, in fact, there are a lot of good [disfmarker] I just [pause] was trying to present a [disfmarker] you know [pause] the main ideas. So, I [disfmarker] I [disfmarker] I [disfmarker] you know, ask uh [disfmarker] You [disfmarker] Feel free to ask uh whatever you want, but [pause] I [disfmarker] I want to insist that [pause] it was just an [disfmarker] uh a simplified uh [pause] version, a light version. OK? well, uh [pause] you know finally this algorithm, eh, as I was telling, eh what it's doing is to check [pause] with the receiver [pause] the power level to be used. And it is very simple to see that some advantages [pause] can [disfmarker] some advantage can be obtained, because [pause] the difference is [pause] eh if you don't have power control, you are using all the time the maximum power, if you have power control, [pause] sometimes you will use [pause] less [pause] than the maximum power How often [pause] do you use less power than the maximum? Well, this will [disfmarker] [pause] this will be connected to the motion pattern. OK? Depending how nodes are moving, well [pause] maybe [pause] all the time [pause] all your neighbors are at the maximum distance But, this probably, doesn't l look like uh something very [pause] very uh [pause] [pause] very likely. OK? because well, l [pause] probably y [pause] what you will have [pause] will be some neighbors that are [pause] really close
[speaker003:] Hmm.
[speaker004:] others that are a little bit [pause] far away and finally, [pause] these neighbors that are in the [disfmarker] [pause] in the frontier [pause] of your [disfmarker] of your coverage area. OK.
[speaker003:] Hmm.
[speaker004:] Yeah.
[speaker003:] OK, this is a question not directly related to these things, but maybe [disfmarker] that's why maybe only a short answer. Uh, do you assume that [pause] power control will be issue also in the [pause] next years? In other words, um [pause] is [pause] the [pause] um [pause] success of having more power within the devices in maybe three year, four years, five years, for batteries, and [disfmarker] and [disfmarker] and [disfmarker] [@ @] and sofort so on uh will it be succeeded that you have so much power available that this [pause] difficult mechanism who is in the wireless network will be uh out of scope?
[speaker004:] Mmm. Yeah.
[speaker003:] Because if I have a device which uh can I use maybe for twenty four hours, I do not have, in principle, really the constraint [pause] to uh deal with [disfmarker] with uh power savings.
[speaker004:] Yeah, let [disfmarker] let me [disfmarker] let me answer you uh with a question. Uh, If, for example, your car [pause] uh you [disfmarker] you have uh an endless [pause] uh source of [disfmarker] of gas, do you think [pause] it will [disfmarker] it will be a problem, [pause] the amount of gas your [disfmarker] your car is [disfmarker] is using? OK. It won't be [pause] a problem for your pocket, for your wallet, but maybe [pause] it will be a problem for [pause] the environment. So, [pause] I think that the answer [pause] to your question is [pause] in this line, that [pause] uh if you have an endless uh source of power, [pause] well, maybe it's not a problem, [pause] for the battery uh lasting. But, it is a problem because [pause] you are using more area [pause] than you should. And therefore you are preventing other transmissions to take place [pause] at the same time. And therefore [pause] uh the problem is not only connected to [disfmarker] to the [disfmarker] to the power it is also connected to the net to the global network throughput. OK?
[speaker003:] OK.
[speaker004:] So [disfmarker] But, [pause] again, uh, you know, uh [pause] the [disfmarker] the m If you ask me "what [disfmarker] what do you think what will happen, [pause] in the industry?" What I think that will happen is that they will [pause] try to get [pause] uh [pause] mmm [pause] better [pause] hardware than we have now because now [pause] the problem [pause] with transceivers [pause] is that a lot of power [pause] is uh [pause] consumed [pause] at the logic of the transceiver, and not [pause] uh transmitted to the air. It is not power transferred to the air. So, [pause] the problem now [pause] is that eh most of the power [pause] uh, uh t uh a wireless network [pause] card [pause] is consuming, [pause] is [disfmarker] is [disfmarker] is drawn [pause] by the [disfmarker] by the eh logic control of the card.
[speaker003:] Yeah.
[speaker004:] All the [disfmarker] all the calculations,
[speaker003:] That's what I [disfmarker]
[speaker004:] all the hardware [disfmarker]
[speaker003:] Yeah, that was the reason I'm talking about this is uh [disfmarker]
[speaker004:] So, I am sure that eh [disfmarker] that manufacturers will try to [disfmarker] to squeeze until the [disfmarker] the [disfmarker] [pause] the last ampere f of [disfmarker] [pause] of this eh, let's say, [pause] eh [pause] wasted power, because [pause] what you cannot avoid is, uh to p l the part of the [disfmarker] of the radio frequency power you have to transmit. I mean, this is [disfmarker] this cannot be avoided. But what you can avoid or you can reduce and probably because now it is the main factor, the main consumption factor, [pause] is the logic inside. In the same way, at [disfmarker] as [disfmarker] as it happened with [disfmarker] with processors, for example. Now [pause] processors [pause] are much more [pause] uh power efficient than before. OK?
[speaker003:] Yeah, but anyway, that was the reason for my question. If I save with a lot of difficult mechanism, within the air interface and between the base station or access point and the mobile node, one percent of the power [pause] whereas ninety nine percent is consumed by packet processing and [disfmarker] and [disfmarker] and [disfmarker] and [disfmarker] uh uh C P U or whatever,
[speaker004:] Mm hmm.
[speaker003:] uh [pause] is it worth to have it? If I really, with a normal device [pause] uh with a battery lifetime of maybe twenty four hours, thirty six hours or whatever kind of thing [disfmarker] And I think it will be increased. As the more mobile nodes are in the world the better the battery will be. So that's [disfmarker] was the reason for my question.
[speaker004:] Yeah, pero e
[speaker003:] Yeah, yeah, yeah.
[speaker004:] uh but [disfmarker] Oh, sorry! But even if you [disfmarker] if you don't have to [disfmarker] to worry about eh your power source, [pause] you have to worry about your environment, about not using more resources [pause] that you don't own
[speaker003:] Yeah. Yeah.
[speaker004:] that are uh [pause] shared about [disfmarker] w w among the community.
[speaker003:] Yeah, I g got it. Yeah. Yeah. OK.
[speaker005:] Excuse me [@ @].
[speaker004:] OK.
[speaker005:] If I understood correctly, the mechanism eh [pause] you should eh [pause] look for um the minimum eh [pause] coverage range
[speaker004:] Yeah.
[speaker005:] in order to maximize the throughput of the network.
[speaker004:] Yeah.
[speaker005:] So there [disfmarker] the [disfmarker] the power control eh [pause] algorithm should work, in order to use at each instant of time the minimum power need to reach
[speaker004:] The destination.
[speaker005:] the neighbor. That [disfmarker] Because this is the way [pause] eh [pause] eh more transmissions uh may take [disfmarker] take place at the same time.
[speaker004:] Can take place at the same time.
[speaker003:] Yeah, yeah, yeah, yeah.
[speaker005:] So you need the adaptive mechanism to minimize the coverage range.
[speaker003:] Yeah.
[speaker004:] That's OK. And to [disfmarker] and to get the maximum network throughput.
[speaker005:] That [disfmarker]
[speaker004:] That's [disfmarker] that's the idea. However [disfmarker] however, and uh, it is always [pause] some however, uh [pause] by [pause] applying this uh [pause] greedy mechanism, [pause] in [disfmarker] in [disfmarker] or, [pause] more than greedy in this case, it could be, [pause] say, this stingy mechanism to [disfmarker] trying to avoid [pause] to use any extra space [pause] is also leading [pause] to [pause] a higher level of interference [pause] at the receivers. So, uh at the end of the road, [pause] we have to [pause] uh look for some trade offs [pause] to avoid too much [pause] uh interference [pause] at the receivers. OK? So, [pause] uh at the end we are using a little bit more power [pause] than these [pause] mathematically minimum values. OK? because if not, [pause] the uh the frame error rate or the bit error rate [pause] uh, skyrockets.
[speaker003:] Mm hmm.
[speaker004:] OK? because of the [disfmarker] of high interference levels. A lot of simultaneous transmissions [pause] also means [pause] for [pause] each receiver point of view, [pause] a lot of [pause] neighbors [pause] or [disfmarker] or nodes [pause] transmitting at the same time. And, all the transmitters [pause] uh with the exception of the transmitter [disfmarker] of my transmitter, [pause] are my intereferers and are [disfmarker] [pause] and all of them are producing [pause] less quality reception, so [pause] if they are a lot of them, [pause] well, uh the reception can be [pause] can be uh disturbed. OK? And [disfmarker] [pause] but um, um [pause] this is taking longer than I expected. OK. Let's [disfmarker] let's uh take a k a [disfmarker] a really [disfmarker] a really light uh view at the [disfmarker] at the routing in this [disfmarker] in this network, which is [pause] another important [pause] area of [disfmarker] of research. You know, [pause] in fact there is a [disfmarker] a group at the ITF [pause] [nonvocalsound] uh called "Manit". This working group is [disfmarker] is devoted to [pause] uh try to [disfmarker] to present or to agree [pause] a common protocol [pause] for routing IP traffic [pause] on these eh kind of networks, on these ad hoc networks, Uh, and at this moment [pause] there are, I would say, a lot [pause] of proposals [pause] of different protocols uh for uh end to end traffic and also for multicast traffic, on these networks And eh well some day in the future eh, a protocol should be [pause] chosen but, [pause] for the moment eh [pause] we have several of them [pause] on the table. and eh [pause] any protocol has some advantages and some disadvantages. The basic [disfmarker] [pause] the basic problem we have to solve [pause] in [disfmarker] in these eh [pause] routing protocols [pause] is [pause] the fast eh [disfmarker] [pause] the fast pace at what eh topology changes [pause] can happen. So the problem here is that [pause] now [pause] uh [pause] one node is my neighbor, and next second, [pause] it is not. So any route that was going through this neighbor [pause] now is [disfmarker] is not possible and should change. And the problem is that [pause] well uh an an [pause] if you let me a personal comment, [pause] I think that one error on the group is not to agree [pause] a set [pause] of mobility patterns [pause] to [disfmarker] to do the [disfmarker] [pause] the tests. because [pause] here, [pause] well, mobility is [pause] making [pause] these uh neighborhood relationships to appear or to disappear, So [pause] uh, it should be interesting if we agree [pause] uh a common [disfmarker] a common [pause] set of motion patterns [pause] to perform the tests because if not, well, it's difficult to [disfmarker] [pause] to perform comparisons [pause] uh between one [pause] protocol and another, a different one. But anyway, [pause] now what we have is [disfmarker] is two basic approaches to this [disfmarker] [pause] this problem. Eh, mainly [pause] what they call the practive protocols which are um extensions of [disfmarker] of uh [pause] um back door and link end state routing protocols [disfmarker] distance vectors, sorry, and [disfmarker] and link end state protocols, eh, which are [pause] usually table driven, so [pause] you [pause] have a process, [pause] trying to [disfmarker] to maintain up to date [pause] a set of routing table tables and the nodes and eh every routing de decision [pause] is eh just eh looking up [pause] the table, and sending to the proper [pause] neighbor node and, eh the other [disfmarker] the other set of protocols are using a reactive [pause] uh [pause] approach and these protocols are trying to work on demand, so they are trying [pause] to solve on only [pause] these routers [pause] that are needed so when I want to send [pause] uh, a packet to a [disfmarker] a given destination, [pause] first of all, I have to [pause] figure out the proper route [pause] for this packet. And then, [pause] uh [pause] I'm using [pause] soft routing. I'm [disfmarker] I'm including on the [disfmarker] on the [disfmarker] uh header of this packet, [pause] the set of eh nodes [pause] that should be forwarding this node to the destination. eh [pause] of course, [pause] uh these uh two approaches can be [disfmarker] can be uh somehow mixed and some hybrid proposals are also [pause] on the [pause] on the [pause] paper, and eh these proposals are [disfmarker] are trying to get [pause] the advantages of both [pause] uh mechanisms eh some sometimes [pause] making a kind of combination of [disfmarker] of them uh, let's say, for example, [pause] using [pause] uh [pause] practive approach [pause] for the closer set of nodes, let's say [pause] for the neighbors and maybe [pause] the next level, and, using a reactive approach I mean, as our routing approach, [pause] for [pause] nodes that [pause] are [pause] closer than this practive area. OK? and eh, [pause] well, u e a some multicast protocols [pause] have been proposed [pause] for this scenario too, and, well, they have to deal with the same problems that they're [pause] uh [pause] end to end routing protocols.
[speaker003:] Mmm. What do you mean by multicast protocols?
[speaker004:] Yeah.
[speaker003:] Routing?
[speaker004:] Routing protocols intended for multicast.
[speaker003:] OK. Yeah. OK.
[speaker004:] So, for [disfmarker] for [disfmarker] uh, for sending one to any.
[speaker003:] Yeah.
[speaker004:] Hmm? Uh [pause] well, [pause] the main [disfmarker] the main problems that some of the solutions eh are exhibiting, [pause] is uh [pause] the lack of eh scalability uh mainly [pause] the [pause] source routing protocols [pause] have a problem when you [disfmarker] when you scale from [disfmarker] or scale [pause] scale [pause] badly [pause] from tens of nodes to [disfmarker] to thousands of nodes because, well, you cannot have [pause] uh, uh [pause] let's say, [pause] uh, an endless uh header length. You have a limited [disfmarker] a limited header length.
[speaker003:] And maybe we will have to explain a little bit for those who are not familiar with source routing.
[speaker004:] So [disfmarker]
[speaker003:] You can have the destinations you would like to [disfmarker] or the in [disfmarker] the I P addresses of the intermediate nodes you still know
[speaker004:] Yeah.
[speaker003:] even if it's not the direct neighbor, but one of uh where you really want that the packet went through, [pause] put it in the I P header.
[speaker002:] Mm hmm.
[speaker003:] So, and, this one is going then to this guy and so on and so on, until finally it's reached destination.
[speaker002:] So there are [disfmarker]
[speaker003:] And, that's what I mean, you cannot put it [disfmarker] thousand intermediate nodes in for example,
[speaker002:] OK.
[speaker003:] but to put a thousand I P addresses in the header, so that the packet is for uh forwarded accordingly to [disfmarker]
[speaker002:] So there's more than one IP address in the header,
[speaker003:] Yeah, yeah, yeah, yeah.
[speaker002:] and [disfmarker] OK, I see.
[speaker004:] Something like this So you [disfmarker] your packet [pause] should look like [disfmarker] like this way.
[speaker002:] Do they have to [disfmarker]
[speaker003:] Yeah.
[speaker002:] Do they have to be in order? So [pause] you are looking first for node two and then for node three and so on.
[speaker004:] Yeah.
[speaker003:] Yeah. It's uh [disfmarker] You'll know to remove h [pause] it's h from the header, in principle, and [disfmarker] and so on, until it uh reaches the final destination.
[speaker002:] OK. OK.
[speaker004:] So this [disfmarker] this uh header, well, [pause] it's [disfmarker] it's a problem. Of course, there are also some [disfmarker] [pause] some solutions like uh [pause] uh employing some kind of [disfmarker] of uh [pause] hierarchical source route routing, so you don't have to put [pause] all [pause] the [disfmarker] all the route [disfmarker]
[speaker003:] This one, for instance. that may that the different parts could be one to number four.
[speaker002:] Mm hmm. Mm hmm.
[speaker003:] Maybe two B or three B Yeah, but nevertheless this guy is a [disfmarker] is an gateway in the router for [disfmarker] for this packet, you know. And they remove itself from the header.
[speaker002:] OK.
[speaker003:] Yeah.
[speaker004:] Anoth
[speaker003:] It must be not the whole path, you know.
[speaker004:] Another problem [pause] eh, is [pause] eh trying to provide some quality of service [pause] in these networks, because, well, [pause] em uh change is [disfmarker] is the only thing you know for sure, [pause] here So, [pause] eh [pause] providing quality of service is also [disfmarker] [pause] is quite a challenge [pause] in [disfmarker] in this network. But, again [pause] uh there are some proposals.
[speaker003:] Um, Miguel, are you familiar with these kind of proposals?
[speaker004:] Not really. Not really, because I don't trust [disfmarker] You know, uh, I'm sure that the proposals are OK, but eh [pause] I don't [disfmarker] [pause] I don't think that [disfmarker] [pause] You cannot warr you [disfmarker] you [disfmarker] [pause] I don't think you can warranty [pause] too much in these networks. So, I see [pause] this like a [pause] you know, a [disfmarker] a topic I'm not convinced about. I don't trust you can really provide quality of service, but of course [disfmarker]
[speaker003:] That depends on the service level you want to be. Definitely not a guarantee level. But maybe something like a control load level or something like that, seems to be for me [pause] possible.
[speaker004:] Yeah.
[speaker003:] Right?
[speaker004:] You know, uh if you are curious, uh I can [disfmarker] I can [disfmarker] [pause] I can provide you the n [pause] some of the proposals
[speaker003:] Yeah. Hmm.
[speaker004:] which include [disfmarker]
[speaker003:] Yeah, we can discuss later, off line.
[speaker004:] Yeah.
[speaker003:] OK.
[speaker004:] And eh, finally, [pause] the other [disfmarker] the other thing, which is also under research or under study [pause] is, uh to have some kind of a power aware routing. There are some proposals, too. So that way you could [disfmarker] routing function could be [pause] connected [pause] with uh global or local power consumption. So, for example, you could ask [pause] to u nnn, the network to transmit your packet [pause] with the lowest [pause] uh global [pause] uh consumption or with your [pause] lowest [pause] local consumption, for example. OK? I mean, would the option for me to [disfmarker] to use less power [pause] when sending a packet is to send it to [pause] the closest neighbor. OK, assuming that I'm [disfmarker] I'm also using s or having some kind of power control thing. so that way [pause] transmitting to the closer [disfmarker] close [disfmarker] to my closer node, [pause] is, uh [pause] something that requires [pause] less effort [pause] than sending to a more distant node. Maybe [pause] the closer node [pause] is not a good uh [disfmarker] it is not in the good direction to the [disfmarker] to reach the destination. But [pause] it is for sure [pause] the [disfmarker] the less expensive uh [pause] thing for me. OK? But probably this uh [disfmarker] [pause] this is not [pause] something really useful. And that ca [pause] what can be u really useful [pause] is to reduce the global [pause] power consumption in the routing function. So, because in this way, well, maybe one node is [disfmarker] [pause] is [pause] being forced to use more power but [disfmarker] but if we take a look at the whole thing, [pause] well, we can ask for a [disfmarker] a low [pause] consumption route, well, the same way
[speaker003:] Yeah, but the [disfmarker]
[speaker004:] as we are asking, for example, when we want [pause] uh some packet to be shipped in the real life, [pause] we can go and say well, [pause] we will [disfmarker] we are happy with this [pause] UPS [pause] ground system. What we want w is two day [pause] delivery service, [pause] or w twenty four hours [pause] service, and we are willing to pay more or less [pause] for this service.
[speaker003:] Yeah, but it's [pause] really happened also in the riot case, you know. If I get the wrong route with the RCMP redirects, it's, in principle, then the same.
[speaker004:] Yeah. Yeah. That's O K.
[speaker003:] Yeah, yeah.
[speaker004:] So, these are more or less uh some open problems, and uh [pause] well [pause] just a quick comment about [disfmarker] probably all of use are [pause] now aware [pause] of the availability [pause] of this eh standard [pause] the I triple E eight hundred and two [pause] point eleven uh [pause] in fact it is [disfmarker] it is [pause] powering [pause] you know, uh the evolution of the [disfmarker] [pause] of the [disfmarker] of networking industry in the wireless area. And [pause] in the beginning, [pause] the first adaptors [pause] uh Oops! were [pause] only one and two megabytes per second, but now we [disfmarker] you [disfmarker] you can buy for [disfmarker] for the same price [disfmarker] for even the same price [pause] uh, the new eleven megabytes per second version I've been [pause] use it for [disfmarker] for a while, and it w [pause] can tell you it works pretty well. and uh, [pause] the thing is that these [pause] devices [pause] have [pause] two different modes of operation. One of them, and probably the most popular, [pause] is uh l what we call the "infrastructure mode", where [pause] you have [pause] a set of mobile nodes, and then you have [pause] one or more access points. These access points are uh [pause] in fact providing [pause] the eh [pause] required connectivity [pause] from the mobiles to the [pause] network [pause] to the [pause] m wired network, and from there to the internet usually.
[speaker003:] Yeah, in principle, the base station.
[speaker004:] Yeah, yeah, we can call it a base station.
[speaker003:] Yeah. Yeah.
[speaker004:] And, eh, the other mode of operation [pause] which should be appropriate, for example, for this meeting room example, [pause] uh [pause] doesn't require any [disfmarker] any access point, and in this second case, communication happens [pause] f eh um from one computer to the other at the link ly layer. OK? So, if I want to connect [pause] to uh, let's say, Miguel's, [pause] uh Michael's, uh I [disfmarker] I will send him [pause] a packet, and he will receive it, and that's it. OK, we can build on top of this [pause] some [pause] uh routing algorithm, some ad hoc routing algorithm, but this is out of the scope of the [disfmarker] of the standard.
[speaker003:] Mm hmm.
[speaker004:] And [disfmarker]
[speaker003:] and Miguel, should [disfmarker] I should ask you one question.
[speaker004:] Yeah.
[speaker003:] And uh uh in version one and two you [disfmarker] you have different technologies. You know, frequency hopping, uh two modes and [disfmarker] and [disfmarker] and also infrared.
[speaker004:] Yeah. Yeah.
[speaker003:] Does it still apply for [disfmarker] for the uh [pause] eleven B?
[speaker004:] For the [disfmarker] no. Eleven B is only for [disfmarker] for uh radio and it's only for uh [pause] direct sequences spread spectrum.
[speaker003:] OK, DSS. OK. OK.
[speaker004:] But, in fact, there is an ongoing new version, I think it's c [pause] version A, but it is not uh commercially available which w will use [pause] uh orthogonal frequency division multiplexing
[speaker003:] OK.
[speaker004:] and will get probably twenty five megabits per second. eh [pause] but, again, the will move to five gigahertz, uh five point five gigahertz, eh [pause] gigahertz, [pause] uh [pause] area of a spec expect [disfmarker] uh spectrum But now, uh current devices [pause] are split at [disfmarker] You know, that the old [disfmarker] [pause] the old waveLAN are nine hundred megahertz [pause] version and the new ones are the [disfmarker] the eleven megabits uh are uh two point four m uh ISM band.
[speaker003:] Megahertz, yeah. Mm hmm.
[speaker004:] However, [pause] uh [pause] some old uh waveLANs are also, but not the older ones [disfmarker] [pause] the oldest ones, [pause] are also uh two point four m eh gigahertz. [pause] S
[speaker003:] Uh, gigahertz. Yeah. In the RSM band.
[speaker004:] S And the good thing is that now, [pause] especially with the new version, [pause] all you [disfmarker] you ca you [disfmarker] you are [disfmarker] you start to see [pause] uh compatible products in the market. Because eh [disfmarker] [pause] maybe because it's the, let's say, second version, but also because [pause] I think it's the only way [pause] for this industry to take off. because [pause] uh [pause] previous versions, if you [pause] buy, let's say, waveLAN, [pause] you are tied to waveLAN [pause] al the rest of your life. But now you can [disfmarker] [pause] you can have interoperable products [pause] from several vendors, which is, I think, [pause] what, [pause] in the past, [comment] will [pause] power the ethernet uh revolution You can buy [pause] any [disfmarker] any compatible product and [disfmarker] and you know it will work with the other brand.
[speaker003:] Yeah. And one additional question from myself, but maybe also short, because time it running fast. Uh, I have heard that uh wireless LAN and Bluetooth will have some problems uh that they influence each other.
[speaker004:] In front?
[speaker003:] Do you have additional information about this topic?
[speaker004:] Yeah. Mmm. You know, in the beginning, uh what w [pause] the [disfmarker] I think that [pause] to put things in perspective, [pause] what we [pause] need to know is [pause] what Bluetooth is and what [pause] Bluetooth is for. And uh Bluetooth is mainly for [pause] cutting [pause] this cable. You know, the other day I was joking about [pause] that our wireless microphones [pause] were not, in fact, [pause] wireless because it had this wire, So, the point is [pause] that eh Bluetooth is mainly a technology [pause] for cutting these kind of cables. You know, sh oh short [disfmarker] short distance cables,
[speaker003:] Yeah, that's right. Yeah. Yeah.
[speaker004:] uh, carrying usually [pause] really s uh, sh [disfmarker] nnn, nnn slow signals, or [pause] let's say, boys and something like this.
[speaker003:] Yeah, but nevertheless, you have the range of ten meters, or of one hundred meters.
[speaker004:] Yeah. Yeah, but you know, uh in fact
[speaker003:] OK.
[speaker004:] uh [pause] the initial version [pause] had only the [disfmarker] the range of ten meters, and I guess that somebody at [pause] a certain meeting [pause] said "OK, why don't we have [pause] a l an extended range version, so we could [pause] re use the same technology for other purposes, different [pause] than the original ones." So, em, uh, I have the feeling that this is [disfmarker] [pause] u this is what is uh [pause] introducing some confor confusion [pause] in the [disfmarker] [pause] in the Bluetooth eh [disfmarker] [pause] or in the way people is [disfmarker] is looking at Bluetooth because they can say OK, hundred meters is [disfmarker] is [disfmarker] [pause] is [pause] an acceptable distance, let's say, for communicating inside a building, inside a [disfmarker] a small office. So, [pause] uh some people, I think, is being tempted to [pause] think that Bluetooth could [pause] provide them [pause] uh, some kind of local connectivity, but [pause] uh for [disfmarker] for data for computing [pause] uses. Eh, however, I think that the [disfmarker] that the [disfmarker] [pause] When you have tried [pause] uh [pause] current eh standard eh working devices, [pause] you [disfmarker] you [disfmarker] working at [disfmarker] at eleven megabits per second, you cannot [disfmarker] [pause] you cannot switch to another thing, to another slower thing. But uh [pause] even when they are using the same [disfmarker] the same uh, um [pause] area of a s a spectrum, because Bluetooth is also intended to work in two point four uh gigabits,
[speaker003:] Yeah.
[speaker004:] eh the technologies are different, you know eh Bluetooth [pause] eh is using a frequency hopping system and uh mmm both uh dialing sequence and frequency hopping, [pause] spread the spectrum techniques, [pause] are also intended [pause] to provide uh interference l uh less, uh [pause] data transmission. So, the idea is that [pause] these [pause] two techniques [pause] are intended not to interfere [pause] with any other thing. So, [pause] even when I haven't tried, [pause] and I cannot tell you for sure, [pause] I think that [pause] the only problem [pause] one network will encounter [pause] uh in the presence of the other [pause] is a little bit [pause] of more noise. And this will produce a little bit [pause] less throughput, but nothing more. I don't expect any [disfmarker] any [pause] more problem. even [pause] the [disfmarker] the [disfmarker] the own Bluetooth specification [pause] is also assuming that another Bluetooth [pause] or several Bluetooth [pause] networks [pause] c will be [disfmarker] could be [pause] in the same area of space and they are using the same [pause] hopping technology, frequency hopping technology. But again, [pause] this technology [pause] is uh trying to avoid [pause] the other networks by choosing different hopping patterns. So [pause] uh [pause] if several Bluetooth networks can [disfmarker] can uh coexist without a problem, [pause] I don't see any problem will [disfmarker] will happen if [disfmarker] if we [pause] want to [disfmarker] to make coexist [pause] one uh Bluetooth with another wireless uh local area network technology.
[speaker003:] Well that's a good news, OK?
[speaker004:] Yeah. I think so.
[speaker003:] But anyway, [vocalsound] um based on your uh uh [pause] initial scenario I believe because Bluetooth is on one chip,
[speaker004:] Yeah.
[speaker003:] like you have now your UCB buss or whatever connectivity, you will have your Bluetooth connectivity.
[speaker004:] Five bucks.
[speaker003:] And that means your mouse, and [disfmarker] and [disfmarker] and [disfmarker]
[speaker004:] Five bucks chip.
[speaker003:] Yeah, and [disfmarker] and [disfmarker] and whatever kind of [disfmarker] of eh things connected to your laptop and also your microphone and whatever you will [disfmarker] will have, is Bluetooth based.
[speaker004:] Hmm hmm hmm.
[speaker003:] Yeah, or will be Bluetooth based.
[speaker004:] Will be.
[speaker003:] Yeah, and this is [disfmarker] this is eh within maybe an uh wireless LAN.
[speaker004:] Will be.
[speaker003:] So, despite the fact that they are considered for different scenarios they are still
[speaker004:] In fact [disfmarker] in fact Bluetooth is also designed
[speaker003:] within one [disfmarker] one area. Yeah.
[speaker004:] to be compatible with existing [pause] digital European cordless telephones. So, hopefully, [pause] we will be able [pause] to use some of [pause] our old devices [pause] or maybe our [disfmarker] our cordless phone base station at home, [pause] with a computer. S S [pause] So I think some really nice applications will [disfmarker] will appear.
[speaker003:] OK we'll when I [disfmarker] I will have some problems in the future with my l [pause] wireless LAN and Bluetooth connectivity, I will come to you, you will solve it OK?
[speaker004:] I'll try to.
[speaker003:] OK, please go on.
[speaker004:] So, [pause] let me [disfmarker] let me just uh finish, you know.
[speaker003:] OK.
[speaker004:] Uh [pause] well, [pause] this is something I, more or less, [pause] I told you. and eh [pause] you know, the point, or [disfmarker] or [disfmarker] or [disfmarker] what [disfmarker] [pause] the [disfmarker] the spark of [disfmarker] of my [disfmarker] [pause] of my work here, or at least, of what I [pause] was proposing to work here, [pause] is [pause] the fact that [pause] these two model uh two modes of operation, I was telling you here [disfmarker] [pause] that you have to choose at the driver level [pause] if your network adaptor [pause] is working in an [pause] access point based environment or in ad ho [pause] in an [pause] ad hoc environment. [pause] I see this as a [disfmarker] as a limitation because I think that [pause] uh when you have to choose among two options, well, mmm, [pause] maybe you are [pause] saying "no" to some of the benefits the other option, [pause] different than the one you are choosing, [pause] could provide you. And I envision an [disfmarker] an [disfmarker] an m [pause] [pause] an escenario [pause] where [pause] eh [disfmarker] Oops! Well, yeah. Let's go. where we can have [pause] a kind of uh dual mode uh wireless network adaptor So [pause] if we are not able [pause] to reach any access point [pause] but we are able to reach another network [pause] node, [pause] well, [pause] maybe this [pause] network node [pause] could do [pause] me the favor [pause] to reach or to forward my packets to the access point. So [pause] the main idea, the driving force here, [pause] is [pause] to uh [pause] try to obtain [pause] uh, let's say, hybrid [pause] mode which allows [pause] an adaptor to work either in the access point or in the [disfmarker] [pause] eh [pause] in the ad hoc mode [pause] in a seamless way. and to include in every single node driver, this forwarding or helper [pause] uh forwarding [pause] mechanism [pause] that [pause] will allow [pause] to extend the wireless coverage [pause] without a need of buying [pause] a lot of access points and putting even an access point inside the restroom. OK? Of course [pause] this idea mmm, [pause] can sound [pause] p can sound a little bit [pause] not very appealing for the manufacturers, at least for the manufacturers of access point because well, they probably are very happy of selling a lot of them.
[speaker003:] But maybe for cars. Yeah, if your car is the infrastructure, for instance.
[speaker004:] Yeah.
[speaker003:] Yeah. OK.
[speaker004:] So, [pause] this is [pause] the m I think this is near the end, this is the last [disfmarker] So One possible extension of the same idea [pause] and something uh I've been thinking for awhile, [pause] is the idea that, well, why can't [pause] do [pause] we [comment] extend this same concept to cell array systems? Why [pause] can't we, [pause] for example, think about [pause] some mmm, [pause] new [pause] mechanisms that users could get, [pause] uh [pause] connectivity by means of other users, [pause] and no directly to the base station, or, [pause] when we have [pause] several technologies [pause] uh in [disfmarker] [pause] overlapped in a certain area, [pause] why can't we use [pause] the closest and the cheapest, maybe, technology, or maybe [pause] the less [pause] power [pause] consumption technology, [pause] without the user to worry about if he is now [pause] using this or [pause] the other technology. And [pause] on the other hand, [pause] what are the billing [pause] implications of this behavior? Because [pause] it is clear that, well, [pause] when I'm [pause] only [pause] uh, talking to the [disfmarker] to the base station of my provider, well [pause] billing is [pause] more or less straightforward, but [pause] what happens [pause] if I'm working [pause] uh, let's say, uh across a mall, [pause] and [pause] at a given moment I'm using [pause] the small [pause] base station of a cordless phone [pause] that is inside the shop I'm at the window of? Well in this case, I'm using [pause] a resource [pause] which is not owned by my provider. I'm using, [pause] a [disfmarker] let's say, a private property. Maybe I have to pay [pause] to this private property, or maybe my carrier [pause] will have to pay or to refund some money to this guy. You know [pause] this something, uh [pause] I'm putting on the table I'm not sure about, [pause] uh [pause] if this can be really of interest or not but, [pause] it's an idea, and I'll be happy to discuss it with you. And I uh [disfmarker] I think [pause] my presentation is over, So.
[speaker003:] Mm hmm. OK. many thanks Miguel. Are there any questions?
[speaker004:] Oh, you are [pause] welcome.
[speaker003:] Maybe we have also the time to discuss with Miguel off line the things if there is some [pause] uh question concerning uh his talk or maybe other questions. Maybe one last question from my side because I bring it up, [pause] uh concerning the proposal, some kind of active routing mechanism.
[speaker004:] Mm hmm.
[speaker003:] It's going in a quite different direction as [disfmarker] as [disfmarker] as [disfmarker] as the traditional things discussed in the ITF and I currently do not have any idea whether active routing is really a topic uh, within the I T Do you have certain kind of experience or do you know certain activities uh, in that area?
[speaker004:] Nnn, no to both q [pause] to both questions.
[speaker003:] OK.
[speaker004:] I don't have previous experience I don't eh know if [disfmarker] uh where it will [disfmarker] [pause] it would fix. However, [pause] eh you know I'm just doing [pause] this presentation uh [pause] some [pause] somehow a review [pause] of my previous work.
[speaker003:] I know, yeah.
[speaker004:] So eh this eh doesn't mean that [disfmarker] I'm [disfmarker] I'm probably [pause] getting involved a little bit more in this active routing thing.
[speaker003:] Mm hmm.
[speaker004:] So uh [pause] I [disfmarker] I [disfmarker] maybe I will be able to [disfmarker] hopefully I will be able to [disfmarker] to give you a better answer in the future.
[speaker003:] Oh, OK. One more time, many thanks Miguel. So.
[speaker004:] Oh, than thanks, Michael, for your computer.
[speaker001:] No problem.
[speaker003:] So I will deploy a little bit information here from the uh project proposal.
[speaker004:] Should I power off it?
[speaker001:] Um, just log out.
[speaker004:] OK.
[speaker001:] Uh. No. Log out.
[speaker004:] Oh, OK, sorry, sorry.
[speaker003:] So I have only four.
[speaker004:] Oh.
[speaker003:] Jordi is [pause] only a short period of time here,
[speaker004:] W which is i which is proper [disfmarker]
[speaker003:] so he will get the [pause] colored one.
[speaker004:] Michael
[speaker005:] Ah, thank you [disfmarker] thank you very much.
[speaker001:] OK.
[speaker004:] Michael,
[speaker003:] and take a look to [disfmarker]
[speaker004:] which is the proper answer?
[speaker003:] uh
[speaker001:] That's the proper answer.
[speaker004:] Th this one?
[speaker001:] Yeah.
[speaker004:] OK.
[speaker003:] Yeah.
[speaker004:] Thank you.
[speaker003:] Kill the computer. Uh, So I started uh, for [disfmarker] for advertising the project proposal here to provide a few slides I think, first of all, Wilbert, is not here, second um, the [pause] um link here [pause] was uh enabling UMTS services and application, uh, I assume [nonvocalsound] was not read [pause] yesterday night. So [pause] I suggest we go roughly to the slides here and um The [disfmarker] the problem is that, in principle, we have different scopes. And motivation of the project proposal from my point of view is that we will have the um Wireless access networks for the next generation will be more flexible. There's a [@ @] for uh current [disfmarker] uh uh uh for [disfmarker] for fast [pause] changes within this network. And that means, if you go to slide number three, [nonvocalsound] that [pause] we [pause] have [pause] um [pause] the possibility to [disfmarker] to um [pause] having normal features in the mobile access network, and [disfmarker] and [pause] um and [pause] um [pause] also based on that it belongs normally to one single provider domain, that it is possible to [disfmarker] to uh use novel things and [disfmarker] and [disfmarker] and new protocols and new technologies within this network. On the other hand, in the internet backbone, uh [pause] we [disfmarker] it is i impossible and we see it on several examples like this, MPLS, there's quality of service support, and multicast and all this kind of thing, that, based on the success of the internet backbone, it's become uh [pause] very unflexible, to p uh fo for the provision of these things. So, if [pause] we are going to offer building blocks, and provide novel solutions for the next generation of wireless access networks, taking into account, [pause] without modifying [pause] the end to end scope, then I think it's really beneficial work, also for the use of interactive multimedia application, so [pause] as it is described in the uh [pause] project proposal. Um [pause] the point is that um [pause] to start [pause] with um [pause] a bigger cluster of co uh [pause] of potential partners to do this really really really big work, seems not to be feasible in the next time. because if you have settled everything, and discussed everything and [disfmarker] and [disfmarker] and [disfmarker] and uh [disfmarker] without any money in the background, and a lot of money in the background, that is not uh feasible from my point of view. Nevertheless, I discussed, with a lot of partners, these things. And today, [pause] uh Michael and me, we were on the UCB to discuss with a guy who is a professor who is probably interested in the application stuff. They are going in that direction. They have a small project funded by NSA [disfmarker] NSF, um, f for this "intelligent classroom", is a little bit exaggerated, I believe, but going in that direction. So there are a lot of interest, but without really [pause] hard money in the background, it is very hard to come to the initial steps. And uh Juan Peire, one of the uh members of this NSA group has [pause] uh [pause] identified a certain kind of s start money, I would like to say. So maybe if you start with a small cluster of um the constraints of this funding, and that means uh six universities and [disfmarker] and institutions uh, three in USA and three in Europe. and of course, they are uh including the NSA group and maybe that seems to be very reasonably, for me. But then we have to align the project proposal in that sense. Because then we cannot do [disfmarker] do anything as it is described in the [disfmarker] in the bigger scope. So the point is [pause] um [pause] to reduce the overall picture, which I described in a few words, to the fact that we have really some work packages where we can focus on it, still fitting into the big picture. Yeah? And so that will be the task of the next weeks. And [pause] uh I [pause] hope that everybody is doing his homework concerning [@ @] for instance uh alternative to the intelligent classroom maybe that we [pause] h can start here only with the N S A group within this big picture um [pause] with some work that we put the pieces together. Because I believe many are very flexible here accounting also the [pause] future coming uh [pause] joining people of the NSA group, to do some work here. And if [pause] we are starting with a very very very small cluster with a common activity have maybe some starting funding for bigger uh [pause] radius of the [disfmarker] of the [disfmarker] the [disfmarker] the uh [pause] project proposal, with the mind that maybe at the final stage it will becoming a European proposal with this uh the [disfmarker] the whole funding. That's uh [pause] my point, and my picture I have in mind. And I will go definitely back to [pause] Germany the tenth of December. That is fixed now. And I hope we can use these remaining weeks [pause] to have really progress in [disfmarker] uh for the proposal in that sense what I mentioned before.
[speaker004:] Hmm hmm.
[speaker003:] Because then I will make [pause] the advertising that is still worth to stay here, And I hope then Siemens will say OK for me to stay longer here. And then I will come back maybe in the [disfmarker] mid of end of January. So that's uh it's a comment to the proposal. So I think everybody should [pause] consider carefully, [pause] based on this statement I made uh next steps and of course everybody has little bit other work to do but it should be [disfmarker] should be always an ongoing process until I will leave [disfmarker] until the tenth of December.
[speaker002:] You mentioned um six partners of this um work.
[speaker003:] OK.
[speaker002:] So you know already what partners are included. OK I didn't have a look at uh slides,
[speaker003:] Um yeah I will distribute all the things electronically
[speaker002:] OK.
[speaker003:] to all the [disfmarker] OK, take a look to slide of number two,
[speaker002:] Just [disfmarker] I'm just curious.
[speaker003:] Yeah! You see uh uh University of Mannheim, University also these are the official ones,
[speaker002:] Yeah, sure.
[speaker003:] You see that in the ICSI US [disfmarker] on the U S A side, I believe that the home companies and universities are still contributing.
[speaker002:] Mm hmm. Yeah yeah.
[speaker003:] Yeah? but these are then the official ones, and I would like to have them [disfmarker]
[speaker002:] And all of them had agreed, or [disfmarker]?
[speaker003:] They say they are very interested in it.
[speaker002:] OK.
[speaker003:] Yeah? Uh a few words, the University of Mannheim is at location where Joerg Widmer is uh working on it, and I got the statement uh they are very interested in that. They did a lot in the area of um intelligent classroom but nevertheless they did a lot in networking stuff. And University of Uppsala, Sweden, that's the reason I invited uh Christian Tschudin, the professor who did ten years work in [disfmarker] in active routing. And uh [pause] [disfmarker] OK the Universidad Nacional de Educat Yeah. Spanish. Maybe we have a better expert [vocalsound] to pronounce it.
[speaker004:] Universidad Nacional de Educacion a Distancia
[speaker003:] "UNED". I always said "UNED". in Spain, uh this is this university of Juan Peire.
[speaker004:] Yeah.
[speaker003:] And [pause] he is also the one who had recognized uh
[speaker005:] Who is?
[speaker003:] one pair pair
[speaker005:] Perez.
[speaker003:] Not Parez, Peire. PEIRE.
[speaker001:] Paez.
[speaker004:] Paez, Paez
[speaker001:] Paez.
[speaker005:] Ah, Peire.
[speaker003:] No, no, no.
[speaker004:] Paez.
[speaker003:] Not [disfmarker] not Paez. Not. Peire, P [pause] E [pause] I R E. P [pause] E [pause] I R E. You never heard from him?
[speaker005:] No. I don't know.
[speaker003:] You can [disfmarker] I [disfmarker] you can mail him later on the informa
[speaker005:] I don't know who he is. OK.
[speaker003:] Then, of course, the whole N S A group and [pause] also of the coordinator of all the things, then Georgia Tech, I have good relationship to uh the long lasting uh cooperation with Georgia Tech and they did a lot in this area, also related to networking stuff as well as to the intelligent classroom stuff [pause] and the UCB. We still focusing on maybe we can have uh more professors involved which are [pause] working also on the networking stuff as well as on the application stuff, so that [pause] the UCB is clustered as one uh partner but nevertheless with different departments.
[speaker004:] Hmm hmm hmm.
[speaker003:] Yeah. So, [disfmarker] But take a look to the slides, I will uh deploy it um uh electronically.
[speaker004:] Wher where your slides are available?
[speaker003:] Sorry?
[speaker004:] Wher where the slides are available?
[speaker003:] I will send it electronically.
[speaker004:] When?
[speaker003:] After the meeting.
[speaker004:] Ah! You will send it, sorry.
[speaker003:] I will. Future.
[speaker004:] Sorry.
[speaker003:] And, [pause] maybe you take a look to the [pause] uh last two slides, um Um, maybe the GPRS picture is still uh available. So you have, in principle, here now the mapping of [pause] the different areas, um within GPS, and, in principle, the same applies for UMTS. There is no so much different. Um. You always have the SGSN and UMTS, they are called three GSGSN. And you have the protocol stack um in [disfmarker] on the slide number five, to see what uh is going on. And you see the difference. The amazing thing is that you have IP over IP. As you take a look to the [disfmarker] the uh GGSN, you have two IP layer functionality and [disfmarker] and all those things. And you have the [pause] GPS tunnel p uh protocol G T P between the G and the S and the GTSN. And [disfmarker] and so on. So uh I believe they are very very difficult protocols stuck between the uh [disfmarker] between the um um involved nodes, and [pause] making it necessary, in principle, to deal with our four building blocks in um [disfmarker] [vocalsound] yeah, I believe, in a difficult way, if, uh, we have in mind quality of service routing, and [disfmarker] and [disfmarker] uh qualit uh mobility aspects and [disfmarker] and all this kinds of things for [pause] I P layer functionality. So that's, in principle, uh an overview, of the protocol stack and the involved nodes, and I will provide more and more information but um eh I have to also figure out everything from the scratch. I am not a total expert for [disfmarker] for the future [pause] wireless networks. OK. Then I would like to thanks everybody and [pause] if there's no additional question, comment, or [pause] or [pause] other remarks, [pause] I would like to start with reading uh these numbers.
[speaker004:] OK, we have [disfmarker]
[speaker003:] OK, please the next one. OK, thank you Now, please let [disfmarker] don't switch off power, I have to call Adam, so So I suggest, [@ @] now we will have [disfmarker] in a few minutes we will have the coffee break, tea, cake, whatever, [@ @] will [disfmarker] will be offered, and then we will have a [disfmarker] we can have a discussion.