Advanced

Modifying Backoff Freezing Mechanism to Optimize Dense IEEE 802.11 Networks

Karaca, Mehmet LU ; Bastani, Saeed LU and Landfeldt, Björn LU (2017) In IEEE Transactions on Vehicular Technology 66(10). p.9470-9482
Abstract
From experience, it has been well known that the performance of IEEE 802.11 wireless local area networks significantly drops in dense settings, largely driven by poor capacity of the medium access control (MAC) layer. The current 802.11 MAC mechanism utilizes a contention window (CW) for random access, and the CW size is dictated to take discrete values from a bounded finite set. In this paper, with focus on a saturated network scenario, we closely investigate the impacts of the aforementioned constraint and show that the limitations on the CW size are the main MAC bottleneck in dense conditions. Then, in order to tackle this bottleneck, we propose a new backoff scheme that does not attempt to tune the CW but makes a small modification in... (More)
From experience, it has been well known that the performance of IEEE 802.11 wireless local area networks significantly drops in dense settings, largely driven by poor capacity of the medium access control (MAC) layer. The current 802.11 MAC mechanism utilizes a contention window (CW) for random access, and the CW size is dictated to take discrete values from a bounded finite set. In this paper, with focus on a saturated network scenario, we closely investigate the impacts of the aforementioned constraint and show that the limitations on the CW size are the main MAC bottleneck in dense conditions. Then, in order to tackle this bottleneck, we propose a new backoff scheme that does not attempt to tune the CW but makes a small modification in the backoff freezing process to determine the optimal configuration. We prove that our backoff scheme can achieve the maximum network throughput even under densely populated networks (i.e., many contenders), while a maximal compliance with the mentioned constraints is maintained. Then, we turn our attention to minimizing the channel access delay, and propose a variant of our backoff algorithm to accomplish this aim. We further present a new result on the theoretical relation between the optimal configurations for which the throughput is maximized and the delay is minimized. Finally, we note that our modified backoff mechanism does not penalize legacy users and is, therefore, practical for implementation in existing networks, which removes co-existence concerns. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
IEEE Transactions on Vehicular Technology
volume
66
issue
10
pages
9470 - 9482
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:85035758780
  • wos:000413137300068
ISSN
1939-9359
DOI
10.1109/TVT.2017.2705343
language
English
LU publication?
yes
id
8f3f84e0-8779-4bdf-9582-91ce8a91090b
date added to LUP
2017-05-01 11:07:54
date last changed
2018-04-29 04:38:17
@article{8f3f84e0-8779-4bdf-9582-91ce8a91090b,
  abstract     = {From experience, it has been well known that the performance of IEEE 802.11 wireless local area networks significantly drops in dense settings, largely driven by poor capacity of the medium access control (MAC) layer. The current 802.11 MAC mechanism utilizes a contention window (CW) for random access, and the CW size is dictated to take discrete values from a bounded finite set. In this paper, with focus on a saturated network scenario, we closely investigate the impacts of the aforementioned constraint and show that the limitations on the CW size are the main MAC bottleneck in dense conditions. Then, in order to tackle this bottleneck, we propose a new backoff scheme that does not attempt to tune the CW but makes a small modification in the backoff freezing process to determine the optimal configuration. We prove that our backoff scheme can achieve the maximum network throughput even under densely populated networks (i.e., many contenders), while a maximal compliance with the mentioned constraints is maintained. Then, we turn our attention to minimizing the channel access delay, and propose a variant of our backoff algorithm to accomplish this aim. We further present a new result on the theoretical relation between the optimal configurations for which the throughput is maximized and the delay is minimized. Finally, we note that our modified backoff mechanism does not penalize legacy users and is, therefore, practical for implementation in existing networks, which removes co-existence concerns.},
  author       = {Karaca, Mehmet and Bastani, Saeed and Landfeldt, Björn},
  issn         = {1939-9359},
  language     = {eng},
  number       = {10},
  pages        = {9470--9482},
  publisher    = {IEEE--Institute of Electrical and Electronics Engineers Inc.},
  series       = {IEEE Transactions on Vehicular Technology},
  title        = {Modifying Backoff Freezing Mechanism  to Optimize  Dense IEEE 802.11 Networks},
  url          = {http://dx.doi.org/10.1109/TVT.2017.2705343},
  volume       = {66},
  year         = {2017},
}