The coded tone sense protocol for multihop spread-spectrum packet radio networks

The use of spread-spectrum techniques in packet radio networks allows overlapping of packet transmission by assigning a different code to each transmitted signal. The authors have designed an algorithm for assigning codes to the stations such that these codes can be reused beyond their interference range. This algorithm can reduce the number of spreading codes required to 20%-35% of the number of stations in the network. Using the code assignment algorithm on slotted ALOHA, the resulting CSA/n protocol can give 42% to 80% performance improvement over the SA protocol. The authors also propose the coded tone sense (CTS) protocol, which can further reduce the number of codes required. From simulation results, it was found that CTS has a much better performance than the BTMA (busy tone multiple access) protocol. For a 80-station network using only five codes, the maximum throughput of CTS is found to be 73% to 80% higher than that of BTMA. It was found that the CSA (coded slotted ALOHA) and CTS protocols are particularly attractive for densely populated networks