An efficient multiuser loading algorithm for OFDM-based broadband wireless systems

Yin, Hujun; Liu, H.

doi:10.1109/glocom.2000.891705

Cited by 254 publications

(154 citation statements)

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“…To reduce the computational load, some suboptimal algorithms have been proposed for MA and RA optimizations in [4]- [6]. However, the use of these algorithms is rather limited for the following reasons: In [4], it is assumed that the average signal-to-noise ratios (SNRs) of all users are identical; [5] is based on a modification of the RA cost; and [6] considers the case where the total transmission power is equally distributed to all subcarriers. Adaptive loading techniques for OFDM systems with multiple antennas have been developed in [7] and [8].…”

mentioning

confidence: 99%

Use of Linear Programming for Dynamic Subcarrier and Bit Allocation in Multiuser OFDM

Kim

Park

Lee

2006

IEEE Trans. Veh. Technol.

185

153

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Abstract-An adaptive subcarrier allocation and an adaptive modulation for multiuser orthogonal frequency-division multiplexing (OFDM) are considered. The optimal subcarrier and bit allocation problems, which are previously formulated as nonlinear optimizations, are reformulated into and solved by integer programming (IP). A suboptimal approach that performs subcarrier allocation and bit loading separately is proposed. It is shown that the subcarrier allocation in this approach can be optimized by the linear-programming (LP) relaxation of IP, while the bit loading can be performed in a manner similar to a single-user OFDM. In addition, a heuristic method for solving the LP problem is presented. The LP-based suboptimal and heuristic algorithms are considerably simpler to implement than the optimal IP, plus their performances are close to those of the optimal approach. Index Terms-Integer programming (IP), linear programming (LP), multiuser orthogonal frequency-division multiplexing (OFDM), subcarrier and bit allocation.

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mentioning

confidence: 99%

Use of Linear Programming for Dynamic Subcarrier and Bit Allocation in Multiuser OFDM

Kim

Park

Lee

2006

IEEE Trans. Veh. Technol.

185

153

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“…Furthermore, in rate adaptive optimization, Jang et al in [6] developed an algorithm, which maximizes the total user's rate subject to the transmitted power constraint. Yin et al in [7] extended the work of [6] while keeping the transmitted power at a minimum rate. Working on rate adaptive optimization, Rhee et al in [8] created an effective subcarrier allocation algorithm which ensures the fairness in resource allocation problems.…”

Section: ⅰ Introductionmentioning

confidence: 99%

“…First, they initialized the number of subcarriers per user based on the reasonable assumption of Yin et al in [7]. Then, after the power allocation, the proportion of subcarriers for each user become nearly equal to the normalized proportionality constants.…”

Section: Subcarrier Allocationmentioning

confidence: 99%

Improved Power Allocation to Enhance the Capacity in OFDMA System for Proportional Resource Allocation

와풋닛¹,

로빈²,

김재명³

2013

The Journal of Korea Information and Communications Society

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Key Words : OFDMA, resource allocation, power allocation, subcarrier allocation, proportionality, waterfilling ABSTRACTThe Orthogonal Frequency Division Multiple Access (OFDMA) is considered as a novel modulation and multiple access technique for 4th generation wireless systems. In this paper, we formulate a base station's power allocation algorithm for each user to maximize the user's sum rate, subject to constraints on total power, bit error rate, and rate proportionality among the users for a better proportional rate adaptive (RA) resource allocation method for OFDMA based system. We propose a novel power allocation method based on the proportion of subcarrier allocation and the user's normalized proportionality constant. We adapt a greedy algorithm and waterfilling technique for allocating the subcarriers among the users. In an end-to-end simulation, we validate that the proposed technique has higher system capacity and lower CPU execution times, while maintaining the acceptable rate proportionality among users.

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“…In general, there are three different approaches to solve such a mixed integer programming problem: The exhaustive search checks all possible subcarrier assignments [16,18], relaxing of constraints transforms integers into real valued variables [11,14] and dual decomposition searches for the optimal CA in the dual domain [16,17]. Yin and Lui [13] showed that the subcarrier allocation for the OFDMA downlink can be solved efficiently by the Hungarian algorithm.…”

Section: Related Workmentioning

confidence: 99%

“…The solution for multiple users in an orthogonal frequency division multiple access (OFDMA) system is more involved due to the additional carrier allocation (CA) problem. OFDMA uplink and downlink have been considered by several authors, and many solutions have been proposed [11][12][13][14][15][16][17][18]. In general, there are three different approaches to solve such a mixed integer programming problem: The exhaustive search checks all possible subcarrier assignments [16,18], relaxing of constraints transforms integers into real valued variables [11,14] and dual decomposition searches for the optimal CA in the dual domain [16,17].…”

Section: Related Workmentioning

confidence: 99%

Resource allocation for the multiple-access relay channels and OFDMA

Schedler

Kühn

2013

EURASIP J. Adv. Signal Process.

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Within this article, the resource allocation problem for the multiple-access relay channel with orthogonal channel access is analysed. We propose a centralised optimisation framework that maximises the achievable sum rate of the network and that can be applied to a wide range of scenarios. We analyse different approaches to tackle the problem with individual transmit power constraints such as relaxing of constraints and splitting of the joint problem into a carrier allocation and individual power allocations. The carrier allocation deals with the exclusive assignment of subcarriers to different users, and the power allocation addresses the distribution of available power over assigned subcarriers. Several approaches are proposed for amplify and forward, decode and forward, and compress and forward strategies, and the performance as well as computational effort is evaluated by simulations. The obtained results suggest that the proposed algorithms can perform close to optimal.

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An efficient multiuser loading algorithm for OFDM-based broadband wireless systems

Cited by 254 publications

References 1 publication

Use of Linear Programming for Dynamic Subcarrier and Bit Allocation in Multiuser OFDM

Use of Linear Programming for Dynamic Subcarrier and Bit Allocation in Multiuser OFDM

Improved Power Allocation to Enhance the Capacity in OFDMA System for Proportional Resource Allocation

Resource allocation for the multiple-access relay channels and OFDMA

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