Joint transmit power and physical carrier sensing adaptation based on loss differentiation for high density IEEE 802.11 WLAN

Abstract

In high density (HD) IEEE 802.11 WLAN, packet loss can occur due to co-channel interference (asynchronous interference) or collisions (synchronous interference). In order to effectively mitigate the interference for spatial reuse, the causes of packet loss should be differentiated and corresponding network parameters (Physical Carrier Sensing (PCS) threshold, transmit power (TXPW) and contention windows size) tuned accordingly. Such loss differentiation ability is not supported by current IEEE 802.11 networks; we devised a novel, zero over-the-air overhead, robust yet accurate method of estimating the probability of collision and interference, respectively. In this work, we investigate how to use differentiated Packet Error Rate (PER) to mitigate asynchronous interference for increasing spatial reuse. Motivated by analysis, a joint transmit power and PCS threshold self-adaptation algorithm based on loss differentiation is proposed. Heuristics that address node starvation and fairness are also incorporated within the above (aggregate throughput maximization) framework to allow a flexible suite of approaches to network tuning. Preprint submitted to Elsevier 2 November 2007Elaborate simulations show that such joint adaptation algorithm can increase both total throughput and worst link throughput in HD WLAN greatly compared with PCS only adaptation without loss differentiation.

Optimizing Aggregate Throughput in 802.11 Networks through Balancing Spatial Reuse and Transmission Rate

“…Although the transmission rate is allowed to be tuned in PRC, the relationship between the level of spatial reuse and the transmission rate has also not been considered. Similar problems exist in the algorithms proposed in [5] [6].…”

Performance enhancement of overlapping BSSs via dynamic transmit power control

“…*Correspondence: wodeying21@kw.ac.kr Department of Electronics Convergence Engineering, Kwangwoon University, 447-1, Wolgye Dong, Nowon-GU, Seoul, Korea Many solutions have been suggested so far to dynamically control the transmit power of WLAN stations and thus to improve the overall throughput of the network [1,[4][5][6][7][8]. By adopting those schemes, stations are able to reduce their transmission ranges using only proper amount of transmit power, such that more stations can simultaneously transmit and thus the overall throughput is increased.…”

“…The previous works, however, may not be adopted in a practical WLAN system: For example, the problem of how to determine the proper power level is not fully investigated in [1,4]. Also [6] is based on assumptions that may not be possible in real world, [7] requires the real-time adaptation of a measurement algorithm, and power control scheme in [8] is limited to use only in ad hoc mode.…”

“…In [7], a run-time self-adaptation algorithm is proposed based on packet loss differentiation, which can jointly adapt both transmit power and physical carrier sensing (PCS) threshold. The problem of this scheme is that it requires metrics such as PER and interference level to be measured in real time which can increase the burden of system.…”

Hybrid Resource Allocation in Wireless Ad Hoc Networks

“…For example, the joint control problem is solved mathematically by breaking down tasks into different layers, and re-designs corresponding protocols [4]. Alternatively, the Dual algorithm is applied to develop a complex price function which considers different factors such as the transmitting power, carrier sensing range and congestion-related metrics [5]. The drawback of this approach is the computation complexity.…”