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Analysis of Parallel Redundant WLAN with Timing Diversity

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Redundancy techniques based on the combination of multiple diverse communication channels are an established countermeasure to improve performance characteristics of wireless communication systems. Besides parallel redundancy in the space and frequency domain, serial redundancy in the time domain can be utilized. It is known that the parallel approaches can significantly improve performance characteristics like jitter and reliability, when applied for wireless packet-based data transmission. In this work, an investigation on the performance impact of additional time diversity on top of the parallel redundancy approaches is performed. An OPNET simulation model is created and analysed for its performance characteristics.
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... The PDA technique we analyze here is called Timed Duplicate Deferral (TDD). A similar solution, not coupled with early termination, was proposed in [23]. TDD is much simpler than the Dynamic Duplicate Deferral (DDD) technique presented in [17], as its operation does not rely on any indication provided at runtime by the MAC layer. ...
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p>Seamless redundancy layered atop Wi-Fi has been shown able to tangibly increase communication quality, hence offering industry-grade reliability. However, it also implies much higher network traffic, which is often unbearable as the wireless spectrum is a shared and scarce resource. To deal with this drawback the Wi-Red proposal includes suitable duplication avoidance mechanisms, which reduce spectrum consumption by preventing transmission on air of inessential frame duplicates. In this paper, the ability of such mechanisms to save wireless bandwidth is experimentally evaluated. To this purpose, specific post-analysis techniques have been defined, which permit to carry out such an assessment on a simple testbed that relies on plain redundancy and do not require any changes to the adapters' firmware. As results show, spectrum consumption decreases noticeably without communication quality is impaired. Further saving can be obtained if a slight worsening is tolerated for latencies.</p
... The PDA technique we analyze here is called Timed Duplicate Deferral (TDD). A similar solution, not coupled with early termination, was proposed in [23]. TDD is much simpler than the Dynamic Duplicate Deferral (DDD) technique presented in [17], as its operation does not rely on any indication provided at runtime by the MAC layer. ...
Preprint
Full-text available
p>Seamless redundancy layered atop Wi-Fi has been shown able to tangibly increase communication quality, hence offering industry-grade reliability. However, it also implies much higher network traffic, which is often unbearable as the wireless spectrum is a shared and scarce resource. To deal with this drawback the Wi-Red proposal includes suitable duplication avoidance mechanisms, which reduce spectrum consumption by preventing transmission on air of inessential frame duplicates. In this paper, the ability of such mechanisms to save wireless bandwidth is experimentally evaluated. To this purpose, specific post-analysis techniques have been defined, which permit to carry out such an assessment on a simple testbed that relies on plain redundancy and do not require any changes to the adapters' firmware. As results show, spectrum consumption decreases noticeably without communication quality is impaired. Further saving can be obtained if a slight worsening is tolerated for latencies.</p
... The PDA technique we analyze here is called Timed Duplicate Deferral (TDD). A similar solution, not coupled with early termination, was proposed in [23]. TDD is much simpler than the Dynamic Duplicate Deferral (DDD) technique presented in [17], as its operation does not rely on any indication provided at runtime by the MAC layer. ...
Preprint
Full-text available
Seamless redundancy layered atop Wi-Fi has been shown able to tangibly increase communication quality, hence offering industry-grade reliability. However, it also implies much higher network traffic, which is often unbearable as the wireless spectrum is a shared and scarce resource. To deal with this drawback the Wi-Red proposal includes suitable duplication avoidance mechanisms, which reduce spectrum consumption by preventing transmission on air of inessential frame duplicates. In this paper, the ability of such mechanisms to save wireless bandwidth is experimentally evaluated. To this purpose, specific post-analysis techniques have been defined, which permit to carry out such an assessment on a simple testbed that relies on plain redundancy and do not require any changes to the adapters' firmware. As results show, spectrum consumption decreases noticeably without communication quality is impaired. Further saving can be obtained if a slight worsening is tolerated for latencies.
... In case of a standard wireless system such as IEEE 802.11 and short cycle times, the transmission reliability can quickly degrade to a point unsuitable for operation of safety applications. Special wireless transmission systems like WSAN-FA or Parallel Redundant WLAN [17], [18] are required for such applications. ...
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