The effects of channel errors on coordinated and non-coordinated medium access control protocols

Abstract

Abstract-In this paper, we investigate the effects of channel noise on the performance of coordinated and non-coordinated MAC protocols. Comparative evaluations of these protocols under a perfect channel assumption have shown that coordinated MAC protocols, which regulate channel access locally, outperform noncoordinated channel access schemes in terms of energy efficiency and throughput. However, coordinated MAC protocols are more vulnerable than non-coordinated MAC protocols to channel noise due to their dependence on the robustness of the control traffic. In order to observe the degradation in performance of a coordinated MAC protocol (MH-TRACE), we investigate the impact of losing control packets. Furthermore, the performance in terms of throughput, delay, and energy efficiency of both coordinated (MH-TRACE) and non-coordinated (IEEE 802.11) MAC protocols is explored using a general error model that takes into account the length of the packets. Our results show that despite its higher level of vulnerability, the coordinated MAC protocol's performance is superior to the performance of the non-coordinated MAC protocol even when error rates are high.Index Terms-Energy-aware systems, distributed networks, wireless communication, network protocols, protocol verification, algorithm/protocol design and analysis, mobile communication systems, access schemes.

An analysis of coordinated and non-coordinated medium access control protocols under channel noise

“…In these results only the specified control packets are lost due to channel errors and all the other packets are not affected [7].…”

“…The overall performance (e.g., QoS, energy dissipation) of these protocols is directly determined by the performance of the MAC protocol for a relatively low bit error rate (BER) level (i.e., BER = 10 −4 ) through ns-2 simulations [7]. We used a single-hop broadcasting scenario to clearly assess the performance of the MAC layer without being affected by the upper layers.…”

“…On the other hand, IEEE 802.11 retains almost 55% of its initial throughput at the same BER (note that the initial throughputs of both protocols are the same). This difference can be translated into the fact that IEEE 802.11 performs 10% better than MH-TRACE, which experiences a worse performance degradation due to lost coordination packets [7].…”

“…However, our previous work showed that throughput per node per second goes into saturation as the number of nodes in the network increases (see Figure 9). This trend is a result of packet collisions and drops emerging from mobility and increased contention for channel access [7]. According to this fact, we have to modify our initial throughput value (throughput when there is a perfect channel) in order to get a more accurate model for throughput.…”

Adaptation of TDMA Parameters Based on Network Conditions

“…TDMA parameters, which determine the amount of spatial reuse and interference, distribute the available bandwidth among clusters so as to reduce the interference throughout the network. Reducing the interference is a desirable goal since high interference leads to high error rates, decreasing the throughput as studied in [7]. However, reducing the available bandwidth per cluster also decreases the capacity per cluster.…”