Blind collision multiplicity detection for wireless access with retransmission diversity

Multiple access protocols with retransmission diversity resolve packet collisions through source separation techniques. The number of retransmissions to achieve the necessary diversity level equals the collision multiplicity, whose proper detection is essential for good performance. The well-known network-assisted diversity multiple access employs the rank test method to detect the multiplicity blindly, but constant channel parameters throughout the retransmissions and the tight control of the transmitter phase are required. In this paper, a superior blind collision multiplicity detection technique is introduced for per-slot varying channels by combining the minimum description length (MDL) criterion and the rank test method. The proposed method and the rank test are compared both theoretically and experimentally.