On improving the performance of IEEE 802.11 with relay-enabled PCF

ABSTRACT

Integrating wireless LAN (WLAN) techniques with the third generation cellular networks has become a promising way to improve the performance of wireless systems. As WLANs play an important role in such heterogeneous systems, the performance of WLANs becomes important to the whole system. It is well known that WLANs provide a physical layer multi-rate capability, and hence MAC layer mechanisms are needed to exploit this capability. In this paper, we propose a novel MAC layer relay-enabled point coordination function (PCF) protocol, called r PCF, to exploit the physical layer multi-rate capability. Since WLAN supports multiple data rates in response to different channel conditions, data packets may be delivered faster through a relay node than through the direct link if the direct link has low quality and low rate. To enable MAC layer relay, the access point needs to collect information about the channel conditions, and notify the mobile nodes which data rate to use and whether to transmit the data through a relay station. We design protocols to achieve this goal and refine these protocols to minimize the control overhead. Simulation results show that r PCF can significantly improve the system performance in terms of system throughput and transmission delay by adding only a negligible control overhead.

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INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.1 PROCESSOR ARCHITECTURES
      C.1.3 Other Architecture Styles
          Subjects: Cellular architecture (e.g., mobile)

Additional Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.2 Network Protocols
          Subjects: Protocol architecture (OSI model)
      C.2.5 Local and Wide-Area Networks
          Subjects: Internet (e.g., TCP/IP)

General Terms:
Algorithms, Design, Performance

Keywords:
IEEE 802.11, media access control, rate adaptation, relay