Multicarrier code division multiple access (MC-CDMA) techniques were originally proposed at mid of 90's for wideband multi-user communications in wireless environments characterised by hostile propagation characteristics. Problems still to be solved are related to the provision of efficient resource channel allocation in variable-bit-rate transmission. In this work, a strategy for medium access control in MC-CDMA systems for broadband WLAN indoor applications is considered. A great advantage of MC-CDMA lies in the capability of supporting asynchronous multi-user variable-bit-rate (VBR) transmission over multipath channel with conventional detection. This can be helpful in designing an efficient and real-time medium access control (MAC) strategy, since a significant number of VBR users can share the same bandwidth without relevant performance dropouts. Different classes of users will be labeled by the MAC level that has to plan a controlled access to the channel on the basis of the users' requests and to check the possibility of assuring to them a certain QoS degree. The paper presents some simulation results in order to discuss the feasibility of the proposed access control strategy.
['Giovanni Berlanda-Scorza', 'Claudio Sacchi', 'Fabrizio Granelli', 'F.G.B. De Natale']
A QoS-oriented medium access control strategy for variable-bit-rate MC-CDMA transmission in wireless LAN environments