Traffic Allocation for Low-Latency Multi-Hop Networks With Buffers

Abstract

For buffer-aided tandem networks consisting of relay nodes and multiple channels per hop, we consider two traffic allocation schemes, namely local allocation and global allocation, and investigate the end-to-end latency of a file transfer. We formulate the problem for generic multi-hop queuing systems and subsequently derive closed-form expressions of the end-toend latency. We quantify the advantages of the global allocation scheme relative to its local allocation counterpart, and we conduct an asymptotic analysis on the performance gain when the number of channels in each hop increases to infinity. The traffic allocations and the analytical delay performance are validated through simulations. Furthermore, taking a specific two-hop network with millimeter-wave (mm-wave) as an example, we derive lower bounds on the average end-to-end latency, where Nakagami-m fading is considered. Numerical results demonstrate that, compared to the local allocation scheme, the advantage of global allocation grows as the number of relay nodes increases, at the expense of higher complexity that linearly increases with the number of relay nodes. It is also demonstrated that a proper deployment of relay nodes in a linear mm-wave network plays an important role in reducing the average end-to-end latency, and the average latency decays as the mm-wave channels become more deterministic. These findings provide insights for designing multi-hop mm-wave networks with low end-to-end latency.

High-Reliability and Low-Latency Wireless Communication for Internet of Things: Challenges, Fundamentals, and Enabling Technologies

“…To minimize latency, we can formulate the problem to optimize traffic allocation with the objective of end-to-end latency. Actually, in [142], we show that for some special networks, e.g., tandem networks with multiple channels in each hop, the minimum latency for both allocation policies can be derived in a recursive way. In Figure 20, performance comparison between local allocation and global allocation is given.…”

“…That is, the relay node work in a full-duplex mode. Traffic allocation has significant impacts to the end-to-end latency for the multi-hop networks with multi-channels in each hop since the traffic congestion at the relay nodes due to non-optimized allocation may lead to long queues and thus large end-to-end latency [142]. Here the end-to-end latency is the time to deliver one fixed-length file .…”

“…The source and the destination are denoted as node n + 1 and node 0, respectively. The hop between the node h + 1 and h is denoted by hop h, where 0 ≤ h ≤ n. Depending the available channel information, there are roughly two types of traffic allocation schemes [142]: global allocation and local allocation, which are described as follows.…”

A Network Coding-Based Braided Multipath Routing Protocol for Wireless Sensor Networks

“…A great deal of research studies [1, 4-7, 9, 13-19] have been carried out on designing routing in WSNs and some new emerging applications [20][21][22][23][24][25] about them, where multipath routing technique and its improvements are one of the most prominent routing. Braided multipath routing, especially network coding-associated braided multipath routing, has become a powerful tool for solving node failures and link loss because of its low redundancy and high reliability during data transmission.…”

“…(1) Upon receiving a packet{OriginID, Flag, SenderID,MainrouterID, Seqnum, PayLoad} (2) If u is the sink then (3) If has enough packets (4) call the decoding procedure; (5) Else (6) waiting for next package; (7) End if (8) Else if senderID is in myChildren set then (9) If flag equals 1 then (10) If senderID is the first one in the parentlist of senderID then (11) If has enough packets (12) update flag and mainrouterID with 1 and u, respectively; (13) Else (14) reencode the packets and generate new packets, update flag and mainrouterID with 1 and u, respectively; (15) End if (16) Else (17) If has enough packets (18) update flag and mainrouterID with 0 and the first ID in the parentlist of senderID, respectively; (19) Else (20) reencode the packets and generate new packets, update flag and mainrouterID with 0 and the first ID in the parentlist of senderID, respectively; (21) End if (22) End if (23) Else if mainrouterID is in myChildren set then (24) If senderID is the first one in the parentlist of mainrouterID then (25) If has enough packets (26) update flag and mainrouterID with 1 and u, respectively; (27) Else (28) reencode the packets and generate new packets, update flag and mainrouterID with 1 and u, respectively; (29) End if (30) Else (31) If has enough packets (32) update flag and mainrouterID with 0 and the first ID in the parentlist of senderID, respectively; (33) Else (34) reencode the packets and generate new packets, update flag and mainrouterID with 0 and the first ID in the parentlist of senderID, respectively; (35) End if (36) End if (37) End if (38)…”