Cross-Layer Optimization for OFDMA-Based Wireless Mesh Backhaul Networks

Karakayali, Kemal; Kang, Jieun; Kodialam, Murali; Balachandran, K.

doi:10.1109/wcnc.2007.57

Cited by 32 publications

(32 citation statements)

References 15 publications

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“…Then the BS initialises the dual variables .0/; .0/ and ".0/. (2) Given .t /, .t/ and ".t / in iteration t, the BS solves 2N per-subcarrier subproblems in Equations (11) and (20) to obtain the optimal subcarrier assignment and the power allocation in the first and second uplink subframes, respectively. based on the results obtained in step 2, calculates subgradients according to Lemma 1 and then updates the dual variables using Equation (8).…”

Section: Algorithm 1: Cross-layer Resource Optimisation For Inelasticmentioning

confidence: 99%

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Cross-layer optimisation for uplink transmission in OFDMA cellular networks with fixed relays

You¹,

Song

et al. 2011

Eur. Trans. Telecomms.

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In this paper, we consider a cross-layer design aimed to enhance performance for uplink transmission in an orthogonal frequency division multiple-access (OFDMA)-based cellular network with fixed relay stations. Because mobile stations (MSs) spend most of the power on the uplink transmission, power efficiency resource allocation becomes very important to MSs. We develop a cross-layer optimisation framework for two types of uplink flows (inelastic and elastic flows) that have different quality-of-service requirements. For inelastic flows with fixed-rate requirement, we formulate the cross-layer optimisation problem as the minimisation of the sum transmission power of MSs under the constraints of flow conservation law, subcarrier assignment, relaying path selection and power allocation. For elastic flows with flexible-service-rate requirement, we consider the cross-layer trade-off between uplink service rate and power consumption of MSs and pose the optimisation problem as the maximisation of a linear combination of utility (of service rates) and power consumption (of MSs). Different trade-offs can be achieved by varying the weighting parameters. Dual decomposition and subgradient methods are used to solve the problems optimally with reduced computational complexity. The simulation results show that, through the proposed cross-layer resource optimisation framework and algorithms, significant benefits of deployment of multiple fixed relays in an OFDMA cellular network can be fully obtained such as reduction in power consumption, increase in service rate and energy savings in the uplink transmission of MSs.

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Section: Algorithm 1: Cross-layer Resource Optimisation For Inelasticmentioning

confidence: 99%

“…For the subgradient at given dual variables, we have the following Lemma. (20), which can be obtained by solving Equations (21), (22) and (23), then …”

Section: Solution Via Dual Problemmentioning

confidence: 99%

Cross-layer optimisation for uplink transmission in OFDMA cellular networks with fixed relays

You¹,

Song

et al. 2011

Eur. Trans. Telecomms.

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“…An improvement on the design in [15] is proposed in [16] by allowing the nodes to reduce interference using a successive cancellation technique. Additional performance gains in OFDMA networks have been sought by incorporating more functionalities in the joint design of the network, e.g., [17], [18]. In [17], a heuristic algorithm is used for performing, possibly suboptimal, routing, scheduling and power allocation for networks in which each node has a prescribed role, either a source, a destination or a relay, and each subchannel is exclusively used by at most one node.…”

Section: Introductionmentioning

confidence: 99%

Routing, Scheduling and Power Allocation in Generic OFDMA Wireless Networks: Optimal Design and Efficiently Computable Bounds

Rashtchi

Gohary

Yanıkömeroğlu

2014

IEEE Trans. Wireless Commun.

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Abstract-The goal of this paper is to determine the data routes, subchannel schedules, and power allocations that maximize a weighted-sum rate of the data communicated over a generic OFDMA wireless network in which the nodes are capable of simultaneously transmitting, receiving and relaying data. Two instances are considered. In the first instance, subchannels are allowed to be time-shared by multiple links, whereas in the second instance, each subchannel is exclusively used by one of the links. Using a change of variables, the first problem is transformed into a convex form. In contrast, the second problem is not amenable to such a transformation and results in a complex mixed integer optimization problem. To develop insight into this problem, we utilize the first instance to obtain efficiently computable lower and upper bounds on the weightedsum rate that can be achieved in the absence of time-sharing. Another lower bound is obtained by enforcing the scheduling constraints through additional power constraints and a monomial approximation technique to formulate the design problem as a geometric program. Numerical investigations show that the obtained rates are higher when time-sharing is allowed, and that the lower bounds on rates in the absence of time-sharing are relatively tight.

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“…Cross layer designs that exploit the broadcast feature of the wireless medium were developed in [9] and [10] using superposition coding and optimization techniques, including geometric programming (GP). Techniques for jointly optimizing the power allocations, the subchannel schedules and the data routes were developed in [11], [12] for networks in which subchannel reuse among multiple nodes is not permitted.…”

Section: Introductionmentioning

confidence: 99%

An efficient cross layer design for OFDMA-based wireless networks with channel reuse

Rashtchi

Gohary

Yanıkömeroğlu

2013

2013 IEEE Global Communications Conference (GLOBECOM)

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Abstract-This paper considers a joint design that incorporates the physical, medium access and network layers of a generic OFDMA-based wireless network with an ad hoc topology. The network employs channel reuse, whereby a frequency subchannel might be used simultaneously by multiple nodes. In addition to being a source and/or a destination, each node can act as a half-duplex relay to assist other nodes. The design objective is to determine the jointly optimal data routes and subchannel power allocations that maximize a weighted sum of the rates that can be reliably communicated over the network. Assuming that the signals transmitted by the nodes are Gaussian, the joint cross layer design of routing and power allocation is cast as an optimization problem. Unfortunately, this problem is non-convex, and hence difficult to solve. To circumvent this difficulty, an efficient technique based on geometric programming is developed to obtain a local solution that satisfies the Karush-Kuhn-Tucker necessary optimality conditions. Numerical results show that, despite the potential suboptimality of the obtained solution, for some network scenarios, it offers significant gains over optimal scheduling-based schemes in which a frequency band is allowed to be used by one node only at any time instant.

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Cross-Layer Optimization for OFDMA-Based Wireless Mesh Backhaul Networks

Cited by 32 publications

References 15 publications

Cross-layer optimisation for uplink transmission in OFDMA cellular networks with fixed relays

Cross-layer optimisation for uplink transmission in OFDMA cellular networks with fixed relays

Routing, Scheduling and Power Allocation in Generic OFDMA Wireless Networks: Optimal Design and Efficiently Computable Bounds

An efficient cross layer design for OFDMA-based wireless networks with channel reuse

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