Voice transmission in an IEEE 802.11 WLAN based access network

Köpsel, Andreas; Wolisz, Adam

doi:10.1145/605991.605995

Cited by 60 publications

(18 citation statements)

References 9 publications

(11 reference statements)

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“…Although there are several schemes [2,14,23,26,35] which use PCF mode to support QoS for real-time traffic, we do not discuss further along this line because PCF is an optional access method [16] which is only usable on infrastructure network configurations and not supported in most current wireless cards. In addition, it may result in poor performance as shown in [25,37,40].…”

Section: Introductionmentioning

confidence: 99%

A call admission and rate control scheme for multimedia support over IEEE 802.11 wireless LANs

2006

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Quality of service (QoS) support for multimedia services in the IEEE 802.11 wireless LAN is an important issue for such WLANs to become a viable wireless access to the Internet. In this paper, we endeavor to propose a practical scheme to achieve this goal without changing the channel access mechanism. To this end, a novel call admission and rate control (CARC) scheme is proposed. The key idea of this scheme is to regulate the arriving traffic of the WLAN such that the network can work at an optimal point. We first show that the channel busyness ratio is a good indicator of the network status in the sense that it is easy to obtain and can accurately and timely represent channel utilization. Then we propose two algorithms based on the channel busyness ratio. The call admission control algorithm is used to regulate the admission of real-time or streaming traffic and the rate control algorithm to control the transmission rate of best effort traffic. As a result, the real-time or streaming traffic is supported with statistical QoS guarantees and the best effort traffic can fully utilize the residual channel capacity left by the real-time and streaming traffic. In addition, the rate control algorithm itself provides a solution that could be used above the media access mechanism to approach the maximal theoretical channel utilization. A comprehensive simulation study in ns-2 has verified the performance of our proposed CARC scheme, showing that the original 802.11 DCF protocol can statically support strict QoS requirements, such as those required by voice over IP or streaming video, and at the same time, achieve a high channel utilization.

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Section: Introductionmentioning

confidence: 99%

A call admission and rate control scheme for multimedia support over IEEE 802.11 wireless LANs

2006

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“…A number of compelling wireless applications such as telephony and video streaming require a relatively low packet delivery delay not exceeding 100-150 ms [21]. We analyze MRD's delay performance here.…”

Section: Delay Analysismentioning

confidence: 99%

Multi-radio diversity in wireless networks

Miu¹,

Balakrishnan²,

Köksal³

2006

Wireless Netw

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This paper describes the Multi-Radio Diversity (MRD) wireless system, which uses path diversity to improve loss resilience in wireless local area networks (WLANs). MRD coordinates wireless receptions among multiple radios to improve loss resilience in the face of path-dependent frame corruption over the radio. MRD incorporates two techniques to recover from bit errors and lower the loss rates observed by higher layers, without consuming much extra bandwidth. The first technique is frame combining, in which multiple, possibly erroneous, copies of a given frame are combined together in an attempt to recover the frame without retransmission. The second technique is a low-overhead retransmission scheme called request-for-acknowledgment (RFA), which operates above the link layer and below the network layer to attempt to recover from frame combining failures. We present an analysis that determines how the parameters for these algorithms should be chosen.We have designed and implemented MRD as a fully functional WLAN infrastructure based on 802.11a. We evaluate the MRD system under several different physical configurations, using both UDP and TCP, and measured throughput gains up to 3× over single radio communication schemes employing 802.11's autorate adaptation scheme.

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“…RELATED WORKS The IEEE 802.11 standard specifies a round-robin (RR) polling mechanism whereby the AP polls the stations in ascending order of their association IDs (AIDs). This algorithm can be applied to poll the active voice stations based on the active list [4,6,7,9]. Because of the simplicity of an RR scheduler, its implementation in an AP is easy.…”

Section: Introductionmentioning

confidence: 99%

A Power-Saving and Robust Point Coordination Function for the Transmission of VoIP over 802.11

Ting

Kuo

Hwang

et al. 2010

International Symposium on Parallel and Distributed Processing With Applications

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Group-polling based schemes for the enhancement of the Point Coordination Function (PCF) in the 802.11 have been supposed to be the most efficient scheme for the transmission of VoIP frame. However, most of the group-polling schemes are not energy-efficient at all due to the fact that all the stations in this list must listen to the channel during all the transmissions belonging to this polling list. Furthermore, if some stations loss this grouppolling frame, it will result in many empty group slots leading to unstable system states. In this article, we propose a Power-Saving and Robust Point Coordination function (PSR-PCF) for the transmission of VoIP over 802.11. Any stations can set its wakeup timer and fall asleep according to the schedule information of the received group polling frame. In order to make this system more robust, we propose a chained-scheme, that is, the MAC address of next active station is piggybacked in the frame header of the uplink data frame to the AP with no additional overheads. Analysis shows that the energy consumption can be reduced by over 93.2% compared with that of ICF [20]. The number of active VoIP stations sustained can be up to about 260 without any data loss under the 802.11a with 54Mbps data rate. Whereas, in the same parameters of 802.11a, the PCF with the Round-Robin (RR) scheduler will have more than 10% data losses if the number of active VoIP stations is larger than 60.

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Voice transmission in an IEEE 802.11 WLAN based access network

Cited by 60 publications

References 9 publications

A call admission and rate control scheme for multimedia support over IEEE 802.11 wireless LANs

A call admission and rate control scheme for multimedia support over IEEE 802.11 wireless LANs

Multi-radio diversity in wireless networks

A Power-Saving and Robust Point Coordination Function for the Transmission of VoIP over 802.11

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