The mechanisms of TCP’s retransmission and reset will result in redundant packets. These redundant packets are often sent unnecessarily to the user over a slow last-hop link delaying useful traffic. This is a problem...The mechanisms of TCP’s retransmission and reset will result in redundant packets. These redundant packets are often sent unnecessarily to the user over a slow last-hop link delaying useful traffic. This is a problem for wide-area wireless links, such as General Packet Radio Service (GPRS), because unnecessary transmissions waste already limited radio bandwidth, battery power at the mobile terminal and incurs monetary cost due to charging by data volume. The paper first describes a GPRS model, then discusses how to eliminate the redundant packets in GPRS network and presents the simulation results in Network Simulation 2 (NS 2). The more traffic is, the more the network can benefit. In heavy traffic, it can even get more than 30% improvement in throughput. Average delay and loss percent are also lowered.展开更多
IEEE 802.11 Medium Access Control (MAC) is proposed to support asynchronousand time bounded delivery of radio packets. Distributed Coordination Function (DCF), which uses Carrier Sense Multiple Access with Collision A...IEEE 802.11 Medium Access Control (MAC) is proposed to support asynchronousand time bounded delivery of radio packets. Distributed Coordination Function (DCF), which uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) and binary slotted exponent ial backoff, is the basis of the 802.11 MAC. This paper proposes a throughput enhancement forDCF by adjusting the Contention Window (CW) setting scheme. Moreover, an analytical modelbased on Markov chain is introduced to compute the enhanced throughput. The accuracy of themodel and the enhancement of the proposed scheme are verified by elaborate simulations.展开更多
This paper proposes an algorithm named WLFVC, which is a fully distributed wireless packet scheduling algorithm based on LFVC (Leap Forward Virtual Clock), to providestreams with fairness, especially in the short time...This paper proposes an algorithm named WLFVC, which is a fully distributed wireless packet scheduling algorithm based on LFVC (Leap Forward Virtual Clock), to providestreams with fairness, especially in the short time scale. This algorithm is able to allocate band-width to streams proportional to their weights. Thus, better delay and jitter performance can beachieved. Since collisions and wireless link error degrade the performance of MAC protocols in the WLAN environment, WLFVC also takes them into consideration. Finally, this algorithm works ina fully distributed way and it can coexist with other stations that only support DCF (Distributed Coordination Function).展开更多
文摘The mechanisms of TCP’s retransmission and reset will result in redundant packets. These redundant packets are often sent unnecessarily to the user over a slow last-hop link delaying useful traffic. This is a problem for wide-area wireless links, such as General Packet Radio Service (GPRS), because unnecessary transmissions waste already limited radio bandwidth, battery power at the mobile terminal and incurs monetary cost due to charging by data volume. The paper first describes a GPRS model, then discusses how to eliminate the redundant packets in GPRS network and presents the simulation results in Network Simulation 2 (NS 2). The more traffic is, the more the network can benefit. In heavy traffic, it can even get more than 30% improvement in throughput. Average delay and loss percent are also lowered.
文摘IEEE 802.11 Medium Access Control (MAC) is proposed to support asynchronousand time bounded delivery of radio packets. Distributed Coordination Function (DCF), which uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) and binary slotted exponent ial backoff, is the basis of the 802.11 MAC. This paper proposes a throughput enhancement forDCF by adjusting the Contention Window (CW) setting scheme. Moreover, an analytical modelbased on Markov chain is introduced to compute the enhanced throughput. The accuracy of themodel and the enhancement of the proposed scheme are verified by elaborate simulations.
文摘This paper proposes an algorithm named WLFVC, which is a fully distributed wireless packet scheduling algorithm based on LFVC (Leap Forward Virtual Clock), to providestreams with fairness, especially in the short time scale. This algorithm is able to allocate band-width to streams proportional to their weights. Thus, better delay and jitter performance can beachieved. Since collisions and wireless link error degrade the performance of MAC protocols in the WLAN environment, WLFVC also takes them into consideration. Finally, this algorithm works ina fully distributed way and it can coexist with other stations that only support DCF (Distributed Coordination Function).
