1. |
- You, Lei, et al.
(författare)
-
Cross-layer optimisation for uplink transmission in OFDMA cellular networks with fixed relays
- 2011
-
Ingår i: European transactions on telecommunications. - : John Wiley & Sons. - 1124-318X .- 2161-3915. ; 22:6, s. 296-314
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
2. |
|
|
3. |
- You, Lei, et al.
(författare)
-
Cross-layer optimization of wireless multihop networks with one-hop two-way network coding
- 2011
-
Ingår i: Computer Networks. - : Elsevier BV. - 1389-1286 .- 1872-7069. ; 55:8, s. 1747-1769
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we investigate optimal cross-layer design of congestion control, routing, one-hop two-way inter-commodity (OTIC) network coding and scheduling in wireless multihop networks utilizing the broadcast advantage of wireless medium. We first present an achievable rate region with OTIC network coding by introducing virtual flow rates in a node. Then we formulate the network utility maximization problem subject to constraints on this achievable rate region, and analyze the complexities of both node- and path-based formulation with no network coding, OTIC network coding, and overhearing network coding. After that, we solve it using dual decomposition and subgradient method. Based on the solution, we present a new queue model, which is able to facilitate the coding operation between two-way commodities, and then propose a backpressure-based cross-layer optimization algorithm with low coding complexity and overhead. Afterwards, we analyze the stability and asymptotical optimality of the proposed cross-layer algorithm by Lyapunov drift technique, and evaluate its performance through extensive simulation. By comparing with the pure routing scheme under both primary and two-hop interference models in an illustrative topology, it is shown that with the proposed joint optimization algorithms, the OTIC network coding can interact adaptively and optimally with other components in different layers and achieve high throughput gain. Simulation of the proposed algorithm in a mesh network with base station and a random ad hoc network justifies that OTIC network coding can obtain considerable throughput gain with low complexity in various kinds of networks.
|
|
4. |
- You, Lei, et al.
(författare)
-
Dynamic Control and Resource Allocation in Wireless-Infrastructured Distributed Cellular Networks with OFDMA
- 2009
-
Ingår i: 2009 INTERNATIONAL CONFERENCE ON PARALLEL PROCESSING WORKSHOPS (ICPPW 2009). - 9781424449231 ; , s. 337-343
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we consider joint optimization of end-to-end data transmission and resource allocation for Wireless-Infrastructured Distributed Cellular Networks (WIDCNs), where each base station (BS) in a cell is connected with its neighboring BSs via wireless links, and a mobile station (MS) can access one or multiple adjacent BSs simultaneously through time-varying OFDMA channels. The communications between a source MS and a destination MS are carried out with the help of BSs in the multi-hop, distributed manner. To achieve the joint optimization for such WIDCNs, a Stochastic Network Utility Maximization (SNUM) problem is formulated under the constraints of OFDMA sub-channel allocation on time-varying access links (both uplink and downlink), as well as routing and scheduling on forwarding links among BSs. By decomposing the corresponding dual problem, transforming it into a stochastic convex optimization problem and solving it by quasi-gradient method, we obtain distributed dynamic control algorithms for end-to-end data transmission. The algorithm can adapt to the OFMDA channel variation and converges asymptotically to the optimal solution. We also develop a distributed algorithm for OFDMA sub-channel allocation and link coordination between BSs. The simulation results show that the data rates of the flows can converge to optimal solution approximately, queues of the network is stable under the proposed distributed dynamic algorithm, and the multi-receiver scheme outperforms the single-receiver scheme due to diversity.
|
|
5. |
|
|