We consider a multi-channel wireless network with user-level CSMA, which consists in running one instance of the CSMA algorithm per active user at each MAC interface . Specifically, each such instance attempts to access a randomly chosen radio channel after some random time and transmits a packet of the corresponding user if the channel is sensed idle . We prove that , unlike the standard CSMA algorithm, this simple distributed access scheme is optimal in the sense that the network is stable for all traffic intensities in the capacity region of the network. Simulations show that capacity (in terms of maximum sustainable traffic) increases by a factor ranging from 1.5 to 2.5 compared to the standard CSMAalgorithm, depending on the network topology and the number of available radio channels .
We analyze the performance of CSMA in multi-channel wireless networks, accounting for the random nature of traffic . Specifically, we assess the ability of CSMA to fully utilize the radio resources and in turn to stabilize the network in a dynamic setting with flow arrivals and departures . We prove that CSMA is optimal in ad-hoc mode but not in infrastructure mode, when all data flows originate from or are destined to some access points, due to the inherent bias of CSMA against downlink traffic. We propose a slight modification of CSMA, that we refer to as flow-aware CSMA, which corrects this bias and makes the algorithm optimal in all cases. The analysis is based on some time-scale separation assumption which is proved valid in the limit of large flow sizes .
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consider a
analyze the performance of CSMA in
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network with user-level CSMA, which consists in running one instance of the CSMA algorithm per active user at each MAC interface
networks, accounting for the random nature of traffic
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each such instance attempts to access a randomly chosen radio channel after some random time and transmits a packet of the corresponding user if the channel is sensed idle
we assess the ability of CSMA to fully utilize the radio resources and in turn to stabilize the network in a dynamic setting with flow arrivals and departures
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, unlike the standard CSMA algorithm, this simple distributed access scheme
CSMA
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the sense that the network is stable for all traffic intensities in the capacity region of the network. Simulations show that capacity (in terms of maximum sustainable traffic) increases by a factor ranging from 1.5 to 2.5 compared to the standard CSMAalgorithm, depending on the network topology and the number of available radio channels
ad-hoc mode but not in infrastructure mode, when all data flows originate from or are destined to some access points, due to the inherent bias of CSMA against downlink traffic. We propose a slight modification of CSMA, that we refer to as flow-aware CSMA, which corrects this bias and makes the algorithm optimal in all cases. The analysis is based on some time-scale separation assumption which is proved valid in the limit of large flow sizes