ieee
IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 18, NO. 3, MARCH 2000
535
Performance Analysis of the IEEE 802.11 Distributed
Coordination Function
Giuseppe Bianchi
Abstract—Recently, the IEEE has standardized the 802.11 protocol for Wireless Local Area Networks. The primary medium access control (MAC) technique of 802.11 is called distributed coordination function (DCF). DCF is a carrier sense multiple access with collision avoidance (CSMA/CA) scheme with binary slotted exponential backoff. This paper provides a simple, but nevertheless extremely accurate, analytical model to compute the 802.11 DCF throughput, in the assumption of finite number of terminals and ideal channel conditions. The proposed analysis applies to both the packet transmission schemes employed by DCF, namely, the basic access and the RTS/CTS access mechanisms. In addition, it also applies to a combination of the two schemes, in which packets longer than a given threshold are transmitted according to the RTS/CTS mechanism. By means of the proposed model, in this paper we provide an extensive throughput performance evaluation of both access mechanisms of the 802.11 protocol.
Index Terms—802.11, collision avoidance, CSMA, performance evaluation. I. INTRODUCTION
I
N recent years, much interest has been involved in the design of wireless networks for local area communication
[1], [2]. Study group 802.11 was formed under IEEE Project
802 to recommend an international standard for Wireless Local
Area Networks (WLAN’s). The final version of the standard has recently appeared [3], and provides detailed medium access control (MAC) and physical layer (PHY) specification for
WLAN’s.
In the 802.11 protocol, the fundamental mechanism to access the medium is called distributed coordination function (DCF).
This is a random access scheme, based on the carrier sense multiple access with collision avoidance (CSMA/CA) protocol. Retransmission of collided packets is
535
Performance Analysis of the IEEE 802.11 Distributed
Coordination Function
Giuseppe Bianchi
Abstract—Recently, the IEEE has standardized the 802.11 protocol for Wireless Local Area Networks. The primary medium access control (MAC) technique of 802.11 is called distributed coordination function (DCF). DCF is a carrier sense multiple access with collision avoidance (CSMA/CA) scheme with binary slotted exponential backoff. This paper provides a simple, but nevertheless extremely accurate, analytical model to compute the 802.11 DCF throughput, in the assumption of finite number of terminals and ideal channel conditions. The proposed analysis applies to both the packet transmission schemes employed by DCF, namely, the basic access and the RTS/CTS access mechanisms. In addition, it also applies to a combination of the two schemes, in which packets longer than a given threshold are transmitted according to the RTS/CTS mechanism. By means of the proposed model, in this paper we provide an extensive throughput performance evaluation of both access mechanisms of the 802.11 protocol.
Index Terms—802.11, collision avoidance, CSMA, performance evaluation. I. INTRODUCTION
I
N recent years, much interest has been involved in the design of wireless networks for local area communication
[1], [2]. Study group 802.11 was formed under IEEE Project
802 to recommend an international standard for Wireless Local
Area Networks (WLAN’s). The final version of the standard has recently appeared [3], and provides detailed medium access control (MAC) and physical layer (PHY) specification for
WLAN’s.
In the 802.11 protocol, the fundamental mechanism to access the medium is called distributed coordination function (DCF).
This is a random access scheme, based on the carrier sense multiple access with collision avoidance (CSMA/CA) protocol. Retransmission of collided packets is
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