Reducing clean cell loss rate in wireless ATM networks

In wireless asynchronous transfer mode (ATM) networks, the bit error rate is high and burst errors may occur in transmission due to jamming and fading. When single-bit error occurs in cell header, it can be easily corrected by the CRC-8 code in the HEC (Header Error Correction) field. However, HEC can not recover the cells with burst errors, and they will be lost or mis-routed accordingly. A strategy to spread each bit of a header field over the entire data field has been proposed to reduce the cell loss probability in wireless ATM networks. In such method, most burst errors are transformed into single-bit errors in header and the HEC is able to recover it. Intuitively, each corrected cell has a higher probability to contain incorrect payload due to burst errors. When network becomes congested, these dirty cells should be dropped first to reduce the number of error cells received by receiver. Meanwhile, the number of retransmitted cells is also reduced. In this paper, the cell payload error probability of a corrected cell is analyzed. A simple cell priority swapping mechanism and the cell discarding strategy are also introduced to reduce the clean cell loss rate on wireless ATM networks. To precisely recognize dirty cells, an efficient hybrid data/header interleaving strategy is proposed. The performance of proposed strategies are investigated by simulation. The simulation results show that the proposed strategies substantially reducing the clean cell loss rate.