Amjad Soomro

Energy-efficient PCF operation of IEEE 802.11a wireless LAN

In this paper, we demonstrate the energy-efficient point coordination function (PCF) operation of IEEE 802.11a wireless LAN (WLAN) via both transmit power control (TPC) and physical layer (PHY) rate adaptation. First, we derive the energy-consumption performance analytically for uplink data transmissions under the PCF. From the evaluation results, we observe that significant energy savings can be achieved by combining TPC with adaptive PHY rate selection. A key requirement for a transmitter to select the most energy-efficient combination of transmit power level and PHY rate is the knowledge of the path loss between the receiver and itself. We present a novel scheme for accurate path loss estimation in 802.11 WLAN. Results and conclusions presented in this paper can serve as a valuable guidance or reference for the design of future 5 GHz 802.11 WLAN systems.

Opportunities and challenges in using WPAN and WLAN technologies in medical environments [Accepted from Open Call]

The present view of medical environments, where isolated networks are used for IT and medical applications, is changing toward an integrated heterogeneous network scenario that can support a wide range of applications. WPAN and WLAN technologies play a fundamental role in enabling such integrated environment that is expected to support both medical and nonmedical applications. The ultimate goal is to exploit WPAN and WLAN technologies, as well as other wireless networks, such as 3G cellular systems and satellite networks, to support highly efficient medical care delivery, anytime and anywhere. However, the life-critical nature of some medical applications imposes additional challenges that have not been considered in nonmedical scenarios. This article discusses some future scenarios where WLAN and WPAN technologies can be used to provide an integrated and ubiquitous network in medical environments, and identifies the main issues to be addressed in order to meet the QoS requirements of different medical applications when operating in integrated environment

Performance Analysis of 802.15.4 and 802.11e for Body Sensor Network Applications

This paper studies the energy efficiency and QoS performance of 802.15.4 and 802.11e MAC protocols for body sensor network applications. We simulated a stand-alone body sensor network, as well as co-existence scenarios where the body sensors operate in the presence of voice, video and IT traffic. Our results indicate that although 802.15.4 and 802.11e can provide an acceptable compromise between power consumption and QoS in some scenarios, there are situations (e.g. co-existence with video and heavy data traffic) in which both performance criteria can not be met simultaneously. This highlights the need for improving existing MAC protocols or designing new solutions that can provide both extremely low power and QoS for body sensor networks (BSNs).

Energy-efficient PCF operation of IEEE 802.11a WLANs via transmit power control

Transmit power control (TPC) has been recognized as one of the effective ways to save energy in wireless devices. In this paper, we demonstrate the energy-efficient point coordination function (PCF) operation of IEEE 802.11a wireless local-area networks (WLANs) via TPC and physical layer (PHY) rate adaptation. The basic idea is that the best transmit power level as well as the proper PHY rate are adaptively selected by a wireless station to transmit an uplink data frame, according to the up-to-date path loss condition between itself and the point coordinator, thus delivering data with minimum energy consumption. Evaluation results show that significant energy savings can be achieved by combining TPC with adaptive PHY rate selection. Note that a key requirement for a wireless station to realize the proposed energy-efficient PCF operation is the knowledge of the path loss, and we present a simple, novel, and effective path loss estimation scheme for this purpose. The results and conclusions presented in this paper should serve as a valuable guidance or reference for the design of future 5 GHz 802.11 WLAN systems.

Achieving Energy Efficiency and QoS for Low-Rate Applications with 802.11e

This paper analyses the energy efficiency and QoS performance of 802.11e as a connectivity solution for low-rate applications, such as wireless automation and monitoring. The authors consider non-interference and co-existence scenarios and show through modeling and simulations that the power save operation mode and the EDCA QoS mechanisms in the 802.11e standard can be exploited to achieve the power consumption requirements of low-rate applications. The authors also provide a comparison of the energy efficiency between 802.11e and 802.15.4 under varying interference and traffic conditions. Our results suggest that in some specific scenarios, 802.11e can achieve higher energy efficiency and QoS than 802.15.4.

A framework for mobile healthcare applications over heterogeneous networks

Future healthcare applications will require operation over heterogeneous networks due to mobility of patient, caregiver and provisioning of healthcare services anytime anywhere. In contrast with applications using protocols for specific networking technologies, we propose to include a unified middleware to isolate applications from mobility management, client discovery and transport of multimedia traffic. We propose an all IP-based framework based on SIP protocol for the unified middleware. The architecture is described. We describe how handovers over heterogeneous networks could be implemented in this architecture which provide better QoS and low packet loss during transitions. A laboratory prototype to demonstrate the above concepts is presented.