Conclusion (VoIP)

13.6
In a multihop wireless network with heavy load, contention becomes the one of the most serious problems. Voice oriented network a in particular, are filled with huge amounts of small packets, all of which contend for the shared network resources. To alleviate this situation and improve network efficiency, we first make the voice packet more efficient to the extent that each packet has a higher information overhead ratio. We pack several MAC packets together and merely hold their MAC destination address. Second, we reduce the protocol overhead, including hand shaking and backoff time through burst broadcast. For small voice packets, 802.11 four way hand shake is too wasteful and burst broadcast becomes an efficient option. We use burst broadcast to relieve a part of contention consumption by the way that it reduces the total amount of DIFS, increases the efficiency of the channel and prevents more contention. Without MAC layer ACK, broadcasts incur more unreliability on one hand, and on the other hand, can reduce contention and delay, and improve background TCP throughput. Therefore, our BQ scheme achieves the tradeoff between contention and reliability.