TY - JOUR

T1 - On the Performance of Largest-Deficit-First for Scheduling Real-Time Traffic in Wireless Networks

AU - Kang, Xiaohan

AU - Wang, Weina

AU - Jaramillo, Juan Jose

AU - Ying, Lei

N1 - Funding Information:
This work was supported in part by the National Science Foundation (NSF) under Grants CNS-1261429, CNS-1264012, and CNS-1262329 and the Defense Threat Reduction Agency (DTRA) under Grant HDTRA1-13-1-0030.

PY - 2016/2

Y1 - 2016/2

N2 - This paper considers the problem of scheduling real-time traffic in wireless networks. We consider ad hoc wireless networks with general conflict graph-based interference model and single-hop traffic. Each packet is associated with a deadline and will be dropped if it is not transmitted before the deadline. The number of packet arrivals in each time-slot and the maximum delay before the deadline are independent and identically distributed across time. We require a minimum fraction of packets to be delivered. At each link, we assume the link keeps track of the difference between the minimum number of packets that need to be delivered so far and the number of packets that are actually delivered, which we call the deficit. The largest-deficit-first (LDF) policy schedules links in descending order according to their deficit values, which is a variation of the longest-queue-first (LQF) policy for non-real-time traffic. We prove that the efficiency ratio of LDF, which is the fraction of the throughput region that LDF can achieve for given traffic distributions, can be lower-bounded by a quantity that we call the real-time local-pooling factor (R-LPF). We further prove that a lower bound on the R-LPF can be related to the weighted sum of the service rates, with a special case of 1/(beta+1) by considering the uniform weight, where beta is the interference degree of the conflict graph. We also propose a heuristic consensus algorithm that can be used to obtain a good weight vector for such lower bounds for given network topology.

AB - This paper considers the problem of scheduling real-time traffic in wireless networks. We consider ad hoc wireless networks with general conflict graph-based interference model and single-hop traffic. Each packet is associated with a deadline and will be dropped if it is not transmitted before the deadline. The number of packet arrivals in each time-slot and the maximum delay before the deadline are independent and identically distributed across time. We require a minimum fraction of packets to be delivered. At each link, we assume the link keeps track of the difference between the minimum number of packets that need to be delivered so far and the number of packets that are actually delivered, which we call the deficit. The largest-deficit-first (LDF) policy schedules links in descending order according to their deficit values, which is a variation of the longest-queue-first (LQF) policy for non-real-time traffic. We prove that the efficiency ratio of LDF, which is the fraction of the throughput region that LDF can achieve for given traffic distributions, can be lower-bounded by a quantity that we call the real-time local-pooling factor (R-LPF). We further prove that a lower bound on the R-LPF can be related to the weighted sum of the service rates, with a special case of 1/(beta+1) by considering the uniform weight, where beta is the interference degree of the conflict graph. We also propose a heuristic consensus algorithm that can be used to obtain a good weight vector for such lower bounds for given network topology.

KW - Fluid limit

KW - largest-deficit-first

KW - local-pooling factor

KW - real-time scheduling

KW - stability

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U2 - 10.1109/TNET.2014.2360365

DO - 10.1109/TNET.2014.2360365

M3 - Article

AN - SCOPUS:84907890719

VL - 24

SP - 72

EP - 84

JO - IEEE/ACM Transactions on Networking

JF - IEEE/ACM Transactions on Networking

SN - 1063-6692

IS - 1

M1 - 6923479

ER -