1,720,962 research outputs found
Cooperative AF wireless relay strategy under relay power constraint
No full textThis paper presents an optimal relay amplifying matrix based on various schemes, such as zero-forcing (ZF) and minimum mean square error (MMSE), for a cooperative amplifyand-forward (AF) wireless relay network consisting of a one source-one-destination pair with a single antenna and one relay with N antennas. The total relay transmission power constraint is employed. Even though different schemes and methods are applied to determine the optimal relay amplifying matrix, the identical one is derived. By adopting the derived optimal relay
amplifying matrix, various analytical and numerical discussions, such as achievable rate (AR), are presented
Two-way amplify-and-forward relay strategies under relay power constraint
No full textThis paper proposes a two-way amplify-and-forward (AF) wireless relay network consisting of two sources with a single antenna and one relay with multiple antennas. The relay amplifying matrix under a power constraint at the relay is presented. The minimum mean square error (MMSE) criterion with self-interference cancelation is employed using vectorization and singular value decomposition (SVD) methods, while the MMSE and matched-filter (MF) criteria without self-interference cancelation are implemented. Using the derived optimal relay amplifying matrix, the average bit error rate (BER) and average mean square error (MSE) behaviors are evaluated
Distributed AF beamforming relay networks under transmit power constraint
No full textThis paper investigates minimum mean square error (MMSE)-based amplify-and-forward (AF) relay amplifying matrices and source/destination beamforming vectors under perfectly known channel state information by imposing constraints on the transmit power of source and relays, separately and individually. The main contribution of this paper is the derivation of a set of relay amplifying matrices and source/destination beamforming vectors under transmit power constraints on the source and relay. Additionally, the SNR and the MMSE cost function behaviors will be investigated numerically and analytically
AF MIMO Wireless Relay Networks Under Received Power Constraint
No full textThis paper considers an amplify-and-forward (AF) relay scheme for M-source-M-destination pairs and N relay nodes. Cooperative minimum mean square error (MMSE) strategies for wireless relay networks under both a jamming environment and channel uncertainty with received power constraints at the destination nodes are studied. The main contribution of this paper is the derivation of the MMSE-based amplifying relay matrices (ARMs) under both a jamming environment and channel uncertainty. With the proposed ARMs, the system performance under study is evaluated by observing bit error rate (BER) using Monte Carlo simulations. In addition, it is proven that the proposed ARM is the global optimal ARM
Two-Way MMSE Strategies for AF Distributed Relay Networks under Power Constraint
No full textThis paper proposes amplify-and-forward (AF) relay strategies for two-way wireless distributed relay networks consisting of two sources with a single antenna per source and multiple N relays with a single antenna per relay. The objective of this paper is to determine optimal relay amplifying matrices (or vectors) under global and local power constraints at the relays based on the minimum mean square error (MMSE) criterion with/without the perfect cancelation of self-interference. With the derived optimal relay amplifying vectors, performances of the
proposed two-way AF distributed relay system are investigated by presenting average bit error rate (BER), average MMSE behavior, and the sum of the achievable rate
Selection of Amplify-and-Forward Mobile Relay under Cascaded Rayleigh Fading
No full textThis paper assumes a practical channel model, called a cascaded Rayleigh fading channel, for a noncooperative distributed mobile relay network, which consists of one mobile source and one mobile destination, and multiple mobile amplifyand-forward (AF) relays. Then, an optimum AF relay amplifying vector (or matrix) is analytically designed using the minimum mean square error (MMSE) criteria and uses it for an efficient mobile relay selection. Power is intentionally not constrained. Instead, this paper presents a scaling factor scheme to meet
a target signal-to-noise ratio (SNRTGT ) at the destination. This SNRTGT strategy can implicitly embrace the power constraint problems and be a more practical implementation
Two-Way AF Wireless Relay Networks under Channel Uncertainty
No full textTwo different two-way amplify-and-forward (AF) wireless relay systems with transmit power constraints at the relay(s) are studied: 1) one-relay system with multiple N antennas between two sources, and 2) multiple N-relay system with one antenna per relay between two sources. The iterative and explicit relay amplifying matrices (or vectors) with perfect cancelation of self-interference under channel uncertainty are determined based on the minimum mean square error (MMSE) criterion. Both iterative and explicit relay amplifying matrices are numerically investigated through the simulation. Simulation results show that the gain of diversity order with channel uncertainty can occur as N increases, while the loss of diversity order can occur as channel estimation error powers increase
Half-Duplex and Full-Duplex Distributed Relay Systems under Power Constraints
No full textThis paper studies relay amplifying matrices and transmitter/receiver beamforming vectors of the amplify-andforward (AF) multiple-input multiple-output (MIMO) halfduplex (HD)/full-duplex (FD) wireless distributed relay systems. The main objective of this paper is to determine a set of relay amplifying matrices and transmitter/receiver beamforming vectors under transmit power constraints at the source and the relays, individually and independently, based on the minimum mean square error (MMSE) criterion. Additionally, the achievable rate and the MMSE cost function (CF) behaviors will be investigated numerically and analytically for both FD and HD distributed relaying systems. Finally, an iterative algorithm is proposed to solve the desired optimization problem
Channel Uncertainty for AF Wireless Distributed Relay Networks under Power Constraint
No full textThis paper presents optimum relay amplifying matrices (or vectors) using the minimum mean square error (MMSE), maximum signal-to-noise ratio (SNR), zero-forcing (ZF), and matched-filter (MF) criteria for an amplify-andforward (AF) wireless distributed relay network with a onesource-one-destination pair and N-relay under the global power constraint (GPC) at the relays in a channel uncertainty (CU) environment. In addition, the local power constraint (LPC) at the relays is also considered for the MMSE criterion. With the derived optimum amplifying relay matrices, cost function and SNR behaviors, achievable rate, and relay selection scheme in the CU environment will be investigated theoretically and evaluated numerically
Two-Way AF MIMO Beamforming Relay Strategies under Transmit Power Constraint
No full textThis paper proposes a two-way amplify-and-forward (AF) multiple-input multiple-output (MIMO) beamforming relay network for the benefit of determining a set of relay amplifying matrices and transmit/receive beamforming vectors by imposing constraints on the transmit power of the sources and relay based on the minimum mean square error (MMSE) criterion. It is proven that minimizing the mean square error (MSE) in the two-way AF MIMO beamforming relay system is equivalent to maximizing the signal-to-noise ratio (SNR). Additionally, various analysis, such as SNR and MMSE cost function, will be investigated. Finally, the iterative algorithm is proposed to solve the desired optimization problem
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