Reducing Power Consumption with QoS Constraints in IEEE 802.16e Wireless Networks

Abstract

Mobile Broadband Wireless Access (BWA) networks will offer in the forthcoming years multiple and differentiated services to users with high mobility requirements, connecting via portable or wearable devices which rely on the use of batteries by necessity. Since a relatively large fraction of energy is consumed by such devices for transmitting/receiving data over-the-air, mechanisms are needed to reduce power consumption, in order to increase the lifetime of devices and hence improve user’s satisfaction. The IEEE 802.16, which supports mobile BWA since its ‘e’ amendment in 2005, defined power saving functions at the Medium Access Control (MAC) layer, which are designed to be operated during open traffic sessions for greatest energy consumption reduction. However, enabling power saving usually increases the transmission latency, which can negatively affect the Quality of Service (QoS) experienced by users. On the other hand, imposing stringent QoS requirements may limit the amount of energy that can be saved. In this paper, an extensive study of the mutual interaction between power saving mechanisms and QoS support is carried out in the context of IEEE 802.16e. In particular, two types of delay-constrained applications with different requirements are considered, i.e., Web and Voice over IP (VoIP), for which the IEEE 802.16e standard specifies two different power saving classes. The performance is assessed via detailed packet-level simulation, with respect to several system parameters. To capture the relative contribution of all the factors on the energy- and QoS-related metrics, part of the evaluation is carried out by means of 2k • r! analysis

Experimental Assessment of Power-Save Behavior of Commercial IEEE 802.16 Network

“…The performance of Sleep mode class type I (PSCI) and class type II (PSCII) of IEEE 802.16e and specifically the interaction between the power saving mechanisms and QoS support (e.g., the delay introduced by the power saving mechanism) were thoroughly investigated in [12]. The performance in [12] was assessed via detailed packet-level simulation whereas in the present paper the performance was evaluated on commercial devices in an operational system.…”

“…The performance in [12] was assessed via detailed packet-level simulation whereas in the present paper the performance was evaluated on commercial devices in an operational system. In addition, [12] examined power saving mechanisms and QoS support of two types of delay-constrained applications with different requirements namely Web and Voice over IP (VoIP), whereas in this paper we investigated power-save mechanism utilization under various traffic patterns.…”

Integrated load-based power saving for BS and MSS in the IEEE 802.16e network

“…The authors claimed that by introduction of periodic traffic indications, the proposed power‐saving scheme was better than the IEEE 802.16e standard in terms of simple implementation, reduction of energy consumption, and saving of the resource. In , an extensive study of the mutual interaction between power‐saving mechanisms and QoS support was carried out for two types of delay‐constrained applications, Web and Voice‐Over‐Internet Protocol, in the context of IEEE 802.16e. The performance was assessed via packet‐level simulation to capture the relative contribution of all the factors on the energy‐related and QoS‐related metrics.…”

“…Most of the researchers in IEEE 802.16e power saving focused on standard type I or II. Related issues in the literature include performance modeling and analysis , enhancement of standard PSC , technique dealing with multiple connections and service types , and novel power‐saving schemes . In addition to power saving at a mobile subscriber station ( MSS ), the idea of a green base station ( BS ) has also attracted some attention, because the power consumption at BS or access point (AP) is much more than at MSS.…”

Comprehensive Performance Analysis and Sleep Window Determination for IEEE 802.16 Broadband Wireless Networks

“…On the other hand, the quality-of-service (QoS) guaranteed services, including unsolicited grant service (UGS) and realtime variable-rate (RT-VR) traffic, are recommended to the PSC of Type II, wherein the length of each sleep window is constant along with the periodic occurrence of transmission-allowed listening windows. The power-saving mechanisms of Types I and II have been investigated with delay-constrained applications such as Web and VoIP traffic respectively in [5]. The other PSC of Type III is appropriate for multicast connections and control management signals.…”