Asynchronous simultaneous small packet transmission in cellular wireless system

Existing cellular wireless systems operate with a predominantly network controlled, connection oriented frame based protocol architecture. A User Terminal (UT) is required to signal the network frequently to maintain its connectivity, and makes requests for uplink bandwidth to transmit packets. In such systems, for emerging applications, such as machine-to-machine (M2M), where small packets are transmitted sporadically, the bandwidth required for signaling is much more than the actual bandwidth to transmit the data. In this paper, we propose a novel connectionless uplink simultaneous access technique without the need of strict synchronization. UTs pick an uplink (UL) resource which is advertised by the network as a common radio resource for small packet transmissions, and transmit the data packets. The data packet includes a preamble sequence and network assigned identity. The transmitted packets from each UT may not be in perfect synchronization with the UL system timing. The base station (BS) uses a novel multi-user detection technique to separate these transmissions. Simulation results of the proposed method for an OFDM based system are shown be promising.