A channel accessing scheme with joint detection receivers in ad hoc networks

In order to achieve high capacity packet transmissions in wireless ad hoc networks, the system throughput for a connectionless, distributed channel accessing scheme exploiting joint detection receivers is proposed and analysed. Joint detection allows many concurrent, asynchronous packet transmissions to occur, thereby enhancing the capacity of a system. A novel packet format with physical layer header's containing an additional code identifier (CID) field as proposed by P. Gupta and P. R. Kumar (March 2000) is employed and CSMA is used for the physical layer header (PLH) of the packet. The data portion of each packet is spread by a unique random binary signature sequence identified by the code identifier field (CID) which allows joint detection of the asynchronous, overlapping packets. A comparison of using CSMA and Aloha multiple access for the PLH is made for a bimodal packet length distribution typical in TCP traffic. Further, an upper hound on the throughput capacity considering the proposed channel accessing schemes is given indicating a significant improvement of system and network throughput is possible with respect to conventional methods.