Fairness aware resource allocation for downlink MISO-OFDMA systems

Abstract

Abstract-In this paper, a resource allocation problem for downlink multiple input-single output orthogonal frequency division multiple access (MISO-OFDMA) systems is investigated. The problem is defined as maximizing the minimum user rate with the constraints of total power and bit error rate (BER). Since it is difficult to obtain the optimal solution to this problem, a suboptimal but efficient solution is proposed based on zero forcing beamforming (ZFBF) to reduce computational complexity. The proposed algorithm is a fairness aware radio resource allocation algorithm that shares the resources equally among the users who has different distances from the Base Station (BS). The simulation results show that the proposed algorithm satisfies the fairness criterion having higher data rates compared to the existing algorithms.

Low complexity QoS-aware subcarrier allocation for MISO-OFDMA systems

“…1(a) shows average sum rate per sub-carrier against signal to noise power ratio (SNR) in dB for K ¼ 10 users for our proposed algorithm, two reference algorithms in [4,5] and Round Robin (RR) algorithm that selects users regardless of channel conditions. Our proposed algorithm outperforms other reference algorithms because it avoids re-allocating sub-carriers step encountered in algorithm [4] Algorithm 1 Proposed Sub-carrier allocation/user selection algorithm that may degrade performance of some users so as to enhance total QoS and also avoids fairness exaggeration encountered in algorithm [5] that may hinder efficient sub-carrier allocation to guarantee fairness. Fig.…”

“…. w T k;n t is the corresponding beamforming vector, p k;n is the power transmitted (homogeneous power allocation among sub-carriers and water-filling among users on same sub-carrier are assumed as in [4,5]), s k;n is transmitted OFDM symbol and z k;n is circular symmetric complex Gaussian noise with zero mean and variance 2 . The first and second terms in (1) denote signal desired component and signal inter-user interference component, respectively.…”

“…In literature, sub-optimal solutions based on linear precoding techniques such as zero-forcing beamforming (ZFBF) [2] have been proposed for inter-user interference cancellation based on linear filtering due to its simple implementation compared to theoretical optimal solution of dirty paper coding (DPC) which is practically very difficult to implement [3]. Also, different user selection algorithms based on ZFBF have been proposed in literature [4,5]. The algorithm in [4] maximizes system capacity with Quality-of-Service (QoS) provision in a two-step resource allocation that preserves minimum user rate for each user, while the algorithm in [5] also maximizes system capacity but selects users based on proportional rates achieved to guarantee fairness among users.…”

“…Also, different user selection algorithms based on ZFBF have been proposed in literature [4,5]. The algorithm in [4] maximizes system capacity with Quality-of-Service (QoS) provision in a two-step resource allocation that preserves minimum user rate for each user, while the algorithm in [5] also maximizes system capacity but selects users based on proportional rates achieved to guarantee fairness among users.…”

Evaluation of Energy-Efficiency Problem in Orthogonal Frequency Division Multiple Access Cellular Networks

“…Once the optimization problem has been established according to the different objective functions (rate maximization, power minimization, energy-efficiency maximization) and different optimization constraints, the problem can be solved optimally or in a heuristic manner. The RRM problem who aims rate maximization and power minimization in OFDMA based cellular networks is studied in many works [7][8][9][10][11][12]. However, these works disregarded the energy consumption of the system which is being a huge problem for the information and communication technology industries.…”