Data packets are transmitted for example in multiple access systems. A multiple access system has the form for example of a point-to-multipoint system, for example a HFC-system, HFR-system, LMDS-system, UMTS-system or hyperLAN-system; HFC=Hybrid Fibre Coax, HFR=Hybrid Fibre Radio, LMDS=Local Multipoint Distribution System, UMTS=Universal Mobile Telecommunications System.
In multiple access systems, in particular delay-sensitive, low-bandwidth services generate only small bandwidths on the path from the terminals to the control centre. Such services are for example VoIP, request signals for web pages, request signals for SoD or the like; VoIP=Voice over Internet Protocol=telephony via the internet, SoD=Service on Demand=services such as  videos, tutorial programs, music on request. The required bandwidths for the use of a service are distinctly below 64 kbit/s. At the same time however, stringent demands are made on the maximum delay jitter, for example in the order of magnitude of 1 to 4 ms.
Prior to each transmission of data packets from the terminals to the control centre, transmit authorizations, for example allocations of time slots, time intervals, codes, frequency channels or arbitrary combinations thereof, are transmitted from the control centre to the terminals. Only after the reception of a transmit authorization is a terminal allowed to transmit a data packet. The access method for the terminals is for example TDMA, CDMA, FDMA or any combination thereof, e.g. TFDMA; TDMA=Time Division Multiple Access, CDMA=Code Division Multiple Access, FDMA=Frequency Division Multiple Access, TFDMA=Time and Frequency Division Multiple Access.
If transmit authorizations are sent to a terminal at a low rate, for example a rate which corresponds to the traffic volume of a VolP application, the time intervals between the individual transmit authorizations and the resultant delay jitter are very large. The delay jitter is for example greater than 10 ms and thus exceeds the permissible maximum.
To fulfill the delay jitter requirement, the rate of the transmit authorizations for each terminal is increased. However, the increased transmit authorization rate inevitably leads to a bandwidth provision which greatly exceeds the bandwidth of the expected traffic volume. In this way a large part of the bandwidth made available remains unused and therefore is wasted. Especially in radio systems in which little bandwidth is available, this has a disadvantageous effect, for example it distinctly limits the number of radio stations in a cell wishing to transmit data packets simultaneously.
USPTO Backgrounds
USPTO Backgrounds