Chain-based multi-hop wireless backhaul networks (WBN) have attracted considerable attention in next-generation networks since they can cost-effectively extend the service coverage area. The major challenge pertaining to such networks is the designing of a high-performance medium access control (MAC) scheme to raise the end-to-end throughput and ensure fairness. In this paper, we propose a novel MAC protocol that is aimed at resolving the well-known location-dependent unfairness problem of chain-based networks, maximizing spatial reuse, and most importantly, achieving exceptional end-to-end throughput. Our scheme provides an elaborate control mini-slots design that resolves the different-relay-traffic-load problem of nodes at various positions near or far from the gateway and further provides local-traffic fairness among all nodes. Moreover, based on the traffic analysis, we provide a four-node group-transmission methodology. By using the neighbor-nodes echoes (broadcasts) the reservation-signals design, the chain-based WBN is allowed to extend to numerous nodes for concurrent and collision-free data transmission through distributed scheduling. Extensive simulation and analytic results also demonstrate that our proposed MAC scheme achieves exceptional system throughput which is approximately 1.6 times better than previous works for a four-node-chain network and also attains high system performance under a wide range of traffic loads and various system parameters.

Long-Reach passive optical networks (LR-PONs) have been considered to be promising solutions for future access networks. In this paper, we proposed a decentralized medium access control (MAC) scheme over an LR-PON network architecture which provides direct inter-ONU communication through an (N+1)×(N+1) star coupler. In the proposed MAC scheme, a profit-weight-based-plus dynamic bandwidth allocation (P-DBA+) scheme is presented. P-DBA+ is a novel excess bandwidth distribution scheme with quality of service (QoS) provisioning. Simulation results indicate that the scheme attains exceptional system performance under various traffic loads and burstiness, providing fair, efficient and robust scheduling, and ensures the QoS requirements.

In this paper, we propose an integrated traffic control scheme (ITCS), which facilitates circuit emulation service (CES) for wireless backhaul over a previously proposed experimental optical packet-switched WDM ring network, HOPSMAN. To ensure efficient setup of CES connections, ITCS employs a simple mean-rate-based distributed admission control followed by a novel slot-marking reservation. The total connection setup delay is comprised of the setup queueing delay and slot-marking delay. While the slot-marking delay is nearly a ring time, the mean setup queueing delay is formally computed through an accurate approximation based on an M/G/m queueing analysis. Simulation results show that ITCS accommodates remarkably high CES traffic loads while satisfying a wide range of delay and jitter requirements for wireless backhaul.

OFDMA-based networks have been considered to be a promising solution to wireless networks especially for broadband multimedia mobile services. In this paper, we propose an enhanced proportional fair (E-PF) scheduling algorithm, which aims at maximizing QoS throughput while still retaining fairness as well as maximizing system throughput in downlink OFDMA systems. Proportional fair (PF) has emerged as a prominent candidate in wireless networks because it achieves a good tradeoff between system throughput and fairness. Nevertheless, the equivalent airtime allocation scheme via PF leads to low throughput of bad channel users, and also limits the attainable QoS throughput of the entire system. E-PF is an enhanced PF-based utility function, which is expected to support QoS and provide a low-complexity algorithm for multi-channel OFDMA networks. We demonstrate via extensive simulation results, that E-PF outperforms PF in terms of system throughput and mean delay. Also, the results show that E-PF well accommodates nearly twice the amount of high priority data than PF does.

In this paper, we propose a novel integrated traffic control scheme, called ITCS, which seamlessly supports connection-oriented and connectionless services for a previously proposed experimental optical packet-switched metro WDM network, HOPSMAN. ITCS aims to efficiently satisfy the diverse quality-of-service (QoS) requirements while retaining maximal network throughput. Through a flexible reservation scheme, ITCS avoids the receiver-contention problem inhered in current WDM network, achieving high statistical multiplexing gain for isochronous traffic. By employing constant mean rate reservation and with an effective distributed call admission control (CAC), ITCS establishes isochronous traffic connections only within a single ring time under normal loads and achieves exceedingly low VBR delay. Furthermore, we develop a novel approximation to acquire the accurate results of the expected connection setup delay by means of an M/G/m queueing analysis. Extensive simulation results show that the mean setup queueing time is in profound agreement with the analytic results, and that ITCS accommodates maximal isochronous traffic with remarkable QoS performance and still retaining exceptional aggregate system throughput.

In this paper, we present the access and control design of a high-performance optical packet-switched WDM metro ring network (HOPSMAN). HOPSMAN has been designed for networks and nodes to be unconstrained by the number of wavelengths. It includes a handful of nodes that are equipped with fast optical slot erasers making bandwidth reusable and achieving greater bandwidth efficiency. In essence, HOPSMAN incorporates a versatile medium access control (MAC) scheme, which embodies efficient and fair bandwidth allocation in accordance with a quota being exerted probabilistically. The quota is analytically derived with the number of slot-eraser-nodes taken into account. The scheme also employs a new notion of credit to regulate flexible access of remaining bandwidth that is suitable for the metro environment with bursty traffic. With the MAC scheme, HOPSMAN is shown to achieve exceptional throughput, delay, and fairness performance under a wide range of traffic settings via simulation results.