CLARA: Closed-Loop Adaptive Rate Allocation for IEEE 802.11 Wireless LANs

Hoffmann, Ceilidh; Manshaei, H.; Turletti, Thierry

doi:10.1109/wirles.2005.1549487

Cited by 24 publications

(34 citation statements)

References 5 publications

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“…CLARA [23] and CARA [24] are similar to our work in [22] and this paper for RTS/CTS access. However, neither CLARA nor CARA provides collision differentiation for basic access.…”

Section: Other Existing Autorate Algorithmssupporting

confidence: 58%

“…In [23], the proposed closed-loop adaptive rate allocation (CLARA) scheme enhanced ARF and mandates the use of RTS/CTS to differentiate losses. If an RTS/CTS exchange is successful, the consequent data loss is very likely due to link error.…”

Section: Other Existing Autorate Algorithmsmentioning

confidence: 99%

“…The RTS/CTS LD was studied in [22] as well. The drawback with the RTS/CTS LD is its overhead, as shown by Pang et al [22], Hoffmann et al [23], and Kim et al [24]. For example, consider 802.11b and assume that the data frame size is 500 B, the data rate is 11 Mb/s, and the basic rate is 2 Mb/s.…”

Section: Other Existing Autorate Algorithmsmentioning

confidence: 99%

“…Therefore, in CLARA, there is a tradeoff between the overhead loss and the potential gain offered by LD with RTS/CTS. A frame size threshold is considered in [23] to decide whether to invoke RTS/CTS. However, as shown in [23], the threshold is quite sensitive to the number of contending stations and channel condition, which may be highly variable in practice, and a practical way to find the threshold has not been provided in [23].…”

Section: Other Existing Autorate Algorithmsmentioning

confidence: 99%

“…A frame size threshold is considered in [23] to decide whether to invoke RTS/CTS. However, as shown in [23], the threshold is quite sensitive to the number of contending stations and channel condition, which may be highly variable in practice, and a practical way to find the threshold has not been provided in [23]. Moreover, even if the threshold is known, when the data frame size is shorter than the threshold, the ability to differentiate losses using RTS/CTS is bypassed.…”

Section: Other Existing Autorate Algorithmsmentioning

confidence: 99%

See 4 more Smart Citations

An Enhanced Autorate Algorithm for Wireless Local Area Networks Employing Loss Differentiation

Pang

Leung

Liew³

2008

IEEE Trans. Veh. Technol.

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Abstract-Channel conditions in wireless local area networks (WLANs) are variable due to mobility and interference. Autorate algorithms are commonly used in WLANs to maximize the data rate over the variable physical channel. However, the widely used automatic rate fallback (ARF) algorithm does not work properly in the presence of multiaccess collisions due to its inability to differentiate frame losses caused by link errors from those caused by collisions. This paper proposes an improved ARF algorithm that is capable of differentiating between these two types of losses with minimal modifications to the existing medium access control protocol. The performance evaluations show substantial throughput improvements over ARF and other existing algorithms.

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“…CLARA [23] and CARA [24] are similar to our work in [22] and this paper for RTS/CTS access. However, neither CLARA nor CARA provides collision differentiation for basic access.…”

Section: Other Existing Autorate Algorithmssupporting

confidence: 58%

Section: Other Existing Autorate Algorithmsmentioning

confidence: 99%

Section: Other Existing Autorate Algorithmsmentioning

confidence: 99%

Section: Other Existing Autorate Algorithmsmentioning

confidence: 99%

Section: Other Existing Autorate Algorithmsmentioning

confidence: 99%

See 3 more Smart Citations

An Enhanced Autorate Algorithm for Wireless Local Area Networks Employing Loss Differentiation

Pang

Leung

Liew³

2008

IEEE Trans. Veh. Technol.

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On selecting the best transmission mode for WiFi devices

Hossein

Lacage

Hoffmann

et al. 2008

Wireless Communications

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The design of efficient IEEE 802.11 physical (PHY) rate adaptation algorithms is a challenging research topic and usually the issues surrounding their implementations on real 802.11 devices are not disclosed. In this paper, we identify and evaluate the key parameters to design such algorithms. We then present a survey on existing PHY rate adaptation mechanisms and discuss their advantages and drawbacks. We also propose three new 802.11 PHY rate adaptation mechanisms, named adaptive auto rate fallback (AARF), closed loop adaptive rate allocation (CLARA), and adaptive multi‐rate retry (AMRR). AARF, proposed for low‐latency systems, has low complexity and obtains similar performance than RBAR in stationary and non‐fading wireless channels. CLARA is a culmination of the best attributes of the transmitter‐based ARF and RBAR control mechanisms with additional practical features such as adaptive fragmentation to improve multipath‐fading channel sensing and to provide feedback control signaling. AMRR is designed for high‐latency systems; it has been implemented and evaluated on an AR5212‐based device. Experimentation results show more than 20% performance improvement in throughput over the default algorithm implemented in the AR5212 MADWIFI driver. Copyright © 2008 John Wiley & Sons, Ltd.

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