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在IEEE 802.11b标准的基础结构操作模式下,DCF的竞争信道访问机制造成上下行链路之间负载不均,限制了VoIP容量的增加.提出一种改进的DCF机制:PDQ-DCF,通过在AP中设置两个不同优先级的区分队列,对语音流量和数据流量区分不同的信道服务参数,均衡AP和STA的语音负载,保证下行链路中语音流量的实时传输,提高语音传输几率.仿真结果表明在保证语音质量的前提下PDQ-DCF机制能够提高语音通信容量.
Under the infrastructure operation mode of IEEE 802.11b standard, DCF competitive channel access mechanism causes load unbalance between uplink and downlink, which limits the increase of VoIP capacity.An improved DCF mechanism is proposed: PDQ-DCF, AP sets up two differentiating queues of different priorities to distinguish different channel service parameters for voice traffic and data traffic and equalize the voice load of APs and STAs so as to ensure the real-time transmission of voice traffic in the downlink and improve the voice transmission probability. The results show that the PDQ-DCF mechanism can improve the voice communication capacity under the premise of ensuring voice quality.