High Throughput Low Delay Wireless Multicast via Multi-Channel Moving Window Codes

Abstract

A fundamental challenge in wireless multicast has been how to simultaneously achieve high-throughput and lowdelay for reliably serving a large number of users. In this paper, we show how to harness substantial throughput and delay gains by exploiting multi-channel resources. We develop a new scheme called Multi-Channel Moving Window Codes (MC-MWC) for multi-channel multi-session wireless multicast. The salient features of MC-MWC are three-fold. (i) High throughput: we show that MC-MWC achieves order-optimal throughput in the manyuser many-channel asymptotic regime. Moreover, the number of channels required by a conventional channel-allocation based scheme is shown to be doubly-exponentially larger than that required by MC-MWC. (ii) Low delay: using large deviations theory, we show that the delay of MC-MWC decreases linearly with the number of channels, while the delay reduction of conventional schemes is no more than a finite constant. (iii) Low feedback overhead: the feedback overhead of MC-MWC is a constant that is independent of both the number of receivers in each session and the number of sessions in the network. Finally, our trace-driven simulation and numerical results validate the analytical results and show that the implementation complexity of MC-MWC is low.• We propose Multi-channel Moving Window Codes (MC-MWC). The key idea behind MC-MWC is a simple Merging strategy, through which multiple multicast sessions can be jointly served by the shared multi-channel 1 We use the standard order notation: for two real-valued sequences {xn} and {yn}, xn = o(yn) if limn→∞ xn/yn = 0; and xn = ω(yn) if limn→∞ xn/yn = ∞; and xn = Ω(yn) if limn→∞ xn/yn ≥ z for some constant z > 0; and xn = Θ(yn) if z 1 ≤ limn→∞ xn/yn ≤ z 2 for some constants z 1 > 0 and z 2 > 0.2 In this paper, we consider the end-to-end delay (including queueing delay and transmission delay), which is measured from the time a packet arrives at the transmitter to the time that the packet is decoded at the receiver. In comparison, the delay metric considered in e.g., [5,6,9,10] only accounts for the transmission delay. arXiv:1801.01613v1 [cs.IT] 5 Jan 2018(55)Consider 1 {I d >k} I d and 1 {Ij >k} as the rewards earned in interval I d . According to the renewal reward theory (see Theorem 11.4 [25]), we have lim J→∞ J d=1 1 {I d >k} mI d J d=1 I d = mE 1 { I>k} I E I , lim J→∞ J d=1 1 {I d >k} J d=1 I d

On NACK-Based rDWS Algorithm for Network Coded Broadcast

“…Numerous literature is available where queueing analysis is done over different kinds of network coded systems to find out improvements in various issues like throughput and delay benefit; trade-offs between coding gain and decoding delay; characterization of capacity region, stability region and throughput region; limitation in feedback's usefulness etc. for various packet injection processes in sender queue (such as stochastic injection, constant data injection, and burst injection) [35][36][37]47,48,[55][56][57]. Among those works, Reference [47] is the first to provide a technique that helps in keeping shorter expected sneder queue (SQ) lengths by exploiting the use of feedback.…”

“…A throughput-delay tradeoff is shown in [54] by careful and dynamic adaption of the transmission rate. Some other works adopted the idea of seeing in their proposed multicast models and showed the throughput and delay improvement of the models [34,35,55,57].…”