Practical Power and Rate Control for WiFi

Abstract

While there has been extensive theoretical work on sophisticated joint resource allocation algorithms for wireless networks, their applicability to WiFi (IEEE 802.11) networks is very limited. One of the main reasons is the limitations in changing MAC parameters in current driver implementations. To this end, in this work, we developed a general cross-layer communication interface in the Linux kernel between the IEEE 802.11 PHY and MAC to enable per packet TPC. Based on this implementation, we realize an decentralized rate-power controller (Minstrel-Piano). Our initial evaluation shows that Minstrel-Piano is able to significantly decrease the power levels while maintaining the same link performance. These results are encouraging for a better interference management and consequently, better resource allocation in WiFi networks.

Rate, power and carrier-sense threshold coordinated management for high-density IEEE 802.11 networks

“…Minstrel-Piano (MP) [6] follows the same idea of transmit power control presented in others works, that is: to transmit at the data rate given by the data rate control with the minimum power possible. Moreover, to control transmit power, this proposal also uses information of the received ACKs to estimate interference.…”

“…In this case the information is at the receiver and not at the transmitter so different techniques are implemented to send this information to the transmitter. Several works [1], [5], [6] claim that this method is difficult to implement because of the complexity of understanding signal propagation and differences in measurements from different hardware. Even more, although exists an standardized metric (RSSI), different hardware report very different values for the same situation as shown in a recent study [7].…”

Experimental Optimization of Exposure Index and Quality of Service in Wlan Networks

“…The third scenario explores a future deployment where WiFi with power control is considered. Recently, efforts have been made towards a standardization of power control in WiFi system, for lower interference, a lower energy consumption, and a lower human exposure [22], [23]. The third scenario will be defined equal to the second scenario, but with added uplink power control.…”

Uncovering a Hidden wireless menace: Interference from 802.11x MAC acknowledgment frames

“…Like MinPACK, some previous proposals also attempt to mitigate interference by controlling transmission power, but they only work with data frames [5,10,12,15,16], and not MAC ACK frames.…”

“…Ramachandran et al [16] proposed a similar data-rate-aware power control algorithm, which considers channel asymmetry as well as client mobility. A more recent work on similar joint data rate and power control mechanism can be found in [10]. In the work by Mhatre et al [15], transmission power and carrier sensing threshold are jointly adjusted to minimize the summed delay of clients.…”