Signature-based fast access coordination in multicarrier wireless networks

Coordination among users is an indispensable part in wireless networks for efficient access control. Alone with the rapid increase of the data transmission rate, however, coordination time becomes insufferable, even several times higher than that for data transmission. We present SIF, a signature-based frequency-domain contention mechanism to achieve high coordination efficiency with low overhead. In SIF, different user is assigned by a different PN sequence as a signature. A contending user issues its signature on some specific OFDM subcarriers and uses the binary sequence of the ON/OFF states of all OFDM subcarriers to deliver the contend information. A signature-based detection method is proposed to detect the CVs of other nodes quickly and reliably. It is shown that, the collision probability of SIF is very low even in a large wireless networks, e.g., less than 0.2% with 100 users. Moreover, as SIF can complete the coordination within one slot in most cases, the throughput gain is up to 200% in comparison with 802.11.