Rate control for semi-TCP in multihop wireless networks

Weiqi Chen, Hua Yu, Quansheng Guan, Yide Wang, Shengming Jiang
2018 EURASIP Journal on Wireless Communications and Networking  
This paper studies the rate control algorithm to improve the performance of semi-TCP, which adopts a buffer-based hop-by-hop congestion control mechanism. By analyzing the impact of the buffer-based sending strategy on the medium contention and interference, we find that this sending strategy is too aggressive to increase the throughput, which leads to severe contention and interference in the channel. Extensive simulations are then carried out and reveal the significance of the channel status
more » ... the channel status of the first hop in rate control. Based on the findings in the simulations, we propose a binary search-based rate control to improve semi-TCP using only local information. The proposed rate control relies on the media status in the first hop to adjust the source rate to approach the peak throughput, without the assistance of end-to-end feedback. Simulation results show the effectiveness of the proposed algorithm in improving the end-to-end throughput and delay. Full list of author information is available at the end of the article drops due to medium contention are the first sign for network overload. Link-layer random early dropping (LRED) and adaptive pacing are then proposed in [9] to stabilize the TCP window size around the best size, where LRED tunes up the link-layer dropping probability according to channel conditions and adaptive pacing extends the range of link-layer contention coordination. Rather than back-offing an additional packet transmission time in [9], the cross-layer TCP pacing in [10] adjusts the contention window to improve throughput. Backward end-to-end acknowledgement (ACK) transmissions also involves in the contention with forward data transmissions for the network resources. Compressing ACKs is another means to improve TCP throughput. The reference [11] proposed to minimize the number of ACK packets by delaying ACK packets according to the channel condition, thus mitigating channel contention and improve TCP's throughput. The above TCP schemes employ the ideas of improving the judgement of network congestion and retain the endto-end semantics of congestion control. The end-to-end congestion control usually needs several round-trip times (RTTs) to detect the congestion in the network, which may respond slowly to the congestion. Particularly for the dynamically changing wireless network, the delayed response may become invalid. Semi-TCP [12, 13] judges the network congestion via the buffer occupancy at each
doi:10.1186/s13638-018-1298-8 fatcat:7kyv3fkrwjbobpayau2bs367m4