DCF+: An enhancement for reliable transport protocol over WLAN

Wu, Hai Tao; Cheng, Shi

doi:10.1007/bf02948885

Cited by 3 publications

(9 citation statements)

References 7 publications

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“…Most Internet services use TCP (Transmission Control Protocol) as a transport-layer protocol and the amount of uplink traffic is expected to increase rapidly due to emerging services such as peer-to-peer contents sharing, audio/video streaming, and mobile video The unfairness problem has been addressed in the literatures [2][3][4][5]. The works in [2] and [3] aim to prevent buffer overflow in the AP by giving the AP more channel access chances.…”

Section: Introductionmentioning

confidence: 99%

“…The works in [2] and [3] aim to prevent buffer overflow in the AP by giving the AP more channel access chances. This can be accomplished by providing high priority to the AP with the aid of differentiated channel access mechanism of IEEE 802.11e [2], or by assuring bi-directional channel access for the STA and AP [3]. However, this approach has a drawback, i.e., the aggregate throughput may be decreased, because the prioritized channel access by the AP increases the probability of collision with STAs [2], or the bi-directional channel access opportunity given to the AP may be wasted due to lack of backlogged TCP ACK [3].…”

Section: Introductionmentioning

confidence: 99%

“…The unfairness problem has been addressed in the literatures [2][3][4][5]. The works in [2] and [3] aim to prevent buffer overflow in the AP by giving the AP more channel access chances. This can be accomplished by providing high priority to the AP with the aid of differentiated channel access mechanism of IEEE 802.11e [2], or by assuring bi-directional channel access for the STA and AP [3].…”

mentioning

confidence: 99%

“…The value of minimum contention window was set to 7 and 15 for the AP and STAs, respectively, to allow the preferential channel access of the AP. This scheme can reduce the TCP ACK loss due to buffer overflow in the AP, which is similar to the idea in [2].• RDG: The RDG (Reverse Direction Grant) mechanism with A-MPDU is employed to grant the bi-directional channel access opportunity to STA and AP, as similar to [3]. If a STA gets the channel access chance and finishes transmitting TCP data packets to the AP, then the channel access opportunity is given to the AP so that the AP can transmit its backlogged TCP ACKs without the channel access procedure.…”

mentioning

confidence: 99%

“…The simulation results show that TAC tightly assures fairness under various network conditions while increasing the aggregate throughput, compared to the existing schemes. The unfairness problem has been addressed in the literatures [2][3][4][5]. The works in [2] and [3] aim to prevent buffer overflow in the AP by giving the AP more channel access chances.…”

mentioning

confidence: 99%

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TCP Acknowledgement Compression for Fairness Among Uplink TCP Flows in IEEE 802.11n WLANs

Kim¹,

Park²,

Kim³

2013

Journal of Institute of Control, Robotics and Systems

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This paper deals with the problem of unfairness among uplink TCP (Transmission Control Protocol) flows associated with frame aggregation employed in IEEE 802.11n WLANs (Wireless Local Area Networks). When multiple stations have uplink TCP flows and transmit TCP data packets to an AP (Access Point), the AP has to compete for channel access with stations for the transmission of TCP ACK (acknowledgement) packets to the stations. Due to this contention-based channel access, TCP ACKs tend to be accumulated in the AP's downlink buffer. We show that the frame aggregation in the MAC (Medium Access Control) layer increases TCP ACK losses in the AP and leads to the serious unfair operation of TCP congestion control. To resolve this problem, we propose the TAC (TCP ACK Compression) mechanism operating at the top of the AP's interface queue. By exploiting the properties of cumulative TCP ACK and frame aggregation, TAC serves only the representative TCP ACK without serving redundant TCP ACKs. Therefore, TAC reduces queue occupancy and prevents ACK losses due to buffer overflow, which significantly contributes to fairness among uplink TCP flows. Also, TAC enhances the channel efficiency by not transmitting unnecessary TCP ACKs. The simulation results show that TAC tightly assures fairness under various network conditions while increasing the aggregate throughput, compared to the existing schemes. The unfairness problem has been addressed in the literatures [2][3][4][5]. The works in [2] and [3] aim to prevent buffer overflow in the AP by giving the AP more channel access chances. This can be accomplished by providing high priority to the AP with the aid of differentiated channel access mechanism of IEEE 802.11e [2], or by assuring bi-directional channel access for the STA and AP [3]. However, this approach has a drawback, i.e., the aggregate throughput may be decreased, because the prioritized channel access by the AP increases the probability of collision with STAs [2], or the bi-directional channel access opportunity given to the AP may be wasted due to lack of backlogged TCP ACK [3]. In [4], the generation of TCP ACK is regulated to assure fairness by intentionally dropping the received TCP data packet in the AP based on its queue occupancy. This is effective to assure fairness, but it may decrease throughput since the TCP data packets that were successfully delivered to the AP are dropped. To mitigate the unfairness among uplink TCP flows, a specific scheduling algorithm is proposed in MAC layer transfers to the lower layer. Also, there are two kinds of ACKs, TCP ACK and MAC ACK, we distinguish them by indicating the terms "TCP" or "MAC" in front of ACK. To our best knowledge, none of the existing studies considers the effect of the IEEE 802.11n frame aggregation on the unfairness problem among uplink TCP flows. This is the very first study revealing that the unfairness problem becomes remarkably exacerbated due to an unintended interaction between MAC frame aggregation and TCP congestion control. Moreover, the ...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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TCP Acknowledgement Compression for Fairness Among Uplink TCP Flows in IEEE 802.11n WLANs

Kim¹,

Park²,

Kim³

2013

Journal of Institute of Control, Robotics and Systems

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TCP-aware bidirectional bandwidth allocation in IEEE 802.16 networks

Park

Kim

2010

Wireless Netw

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In this paper, we propose a bidirectional bandwidth-allocation mechanism to improve TCP performance in the IEEE 802.16 broadband wireless access networks. By coupling the bandwidth allocation for uplink and downlink connections, the proposed mechanism increases the throughput of the downlink TCP flow and it enhances the efficiency of uplink bandwidth allocation for the TCP acknowledgment (ACK). According to the IEEE 802.16 standard, when serving a downlink TCP flow, the transmission of the uplink ACK, which is performed over a separate unidirectional connection, incurs additional bandwidth-request/allocation delay. Thus, it increases the round trip time of the downlink TCP flow and results in the decrease of throughput accordingly. First, we derive an analytical model to investigate the effect of the uplink bandwidth-request/allocation delay on the downlink TCP throughput. Second, we propose a simple, yet effective, bidirectional bandwidth-allocation scheme that combines proactive bandwidth allocation with piggyback bandwidth request. The proposed scheme reduces unnecessary bandwidth-request delay and the relevant signaling overhead due to proactive allocation; meanwhile, it maintains high efficiency of uplink bandwidth usage by using piggyback request. Moreover, our proposed scheme is quite simple and practical; it can be simply implemented in the base station without requiring any modification in the subscriber stations or resorting to any cross-layer signaling mechanisms. The simulation results ascertain that the proposed approach significantly increases the downlink TCP throughput and the uplink bandwidth efficiency.

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Bidirectional bandwidth allocation for TCP performance enhancement in mobile WiMAX networks

Park

Kim

2008

2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications

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DCF+: An enhancement for reliable transport protocol over WLAN

Cited by 3 publications

References 7 publications

TCP Acknowledgement Compression for Fairness Among Uplink TCP Flows in IEEE 802.11n WLANs

TCP Acknowledgement Compression for Fairness Among Uplink TCP Flows in IEEE 802.11n WLANs

TCP-aware bidirectional bandwidth allocation in IEEE 802.16 networks

Bidirectional bandwidth allocation for TCP performance enhancement in mobile WiMAX networks

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