A dynamic adaptive multi-receiver random access protocol for the code division multiple access channel

We present a packet multiple access protocol that is a hybrid of a pure CDMA protocol and an ALOHA random access protocol. The protocol utilizes the multireception capabilities of spread-spectrum communications together with the “statistical-multiplexing” capabilities of random access. We begin by presenting a multi-receiver random access protocol and analyze its throughput characteristics. We then develop collision resolution algorithms for the protocol that attempt to optimize its performance. These algorithms are analyzed through the use of simulation. We show that with proper choice of protocol parameters our protocol can handle all admissible traffic loads. We then propose a dynamic, adaptive extension to the protocol that uses limited feedback information to allow the protocol to vary its parameters based on the traffic load in the system. This dynamic, adaptive version of the protocol allows it to operate efficiently under a wide variety of traffic load conditions. At very light load conditions the protocol behaves as a pure random access protocol and at very high load it behaves as a pure fixed assignments protocol. Our protocol seems to be a good choice for providing random access on a satellite channel where propagation delays are long. It is also a natural choice for wireless transmission of very short (e.g., ATM) packets