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In a two-way relay network, two terminals exchange information with the help of a relay. Due to its fundamental and practical importance, there has been an increasing interest in this channel. Recently, the notation of bottleneck error exponent has been introduced which is the worst exponent decay between the two links, gives us insight into the fundamental tradeoff between the rate pair and the information-exchange...
This paper studies the use of amplify-and-forward (AF) relays for robust beamforming, with the aid of imperfect channel state information (CSI) at the sender. In particular, the maximization of the worst-case signal-to-noise ratio (SNR) at the destination terminal is studied under a bounded spherical region for the norm of CSI error vector. We show that under a condition on the estimated CSI quality,...
We consider an Amplify-and-Forward relay selection for OFDM networks with fairness constraints where a source node communicates with a destination node with the help of one or more relays. The system model assumes all relays participate and considers the subcarrier pairing with fairness constraints on relays. Our subcarrier allocation algorithm is presented to maximize the system capacity based on...
Energy efficiency is a considerable criterion in design of wireless sensor networks. MIMO technology has the potential of supporting a higher data rate under a lower power budget and bit-error-rate, which makes cooperative MIMO in WSNs a popular research topic. This paper investigates a cluster-based time division cooperative MIMO communication system for WSNs. An optimum algorithm for the power and...
3GPP LTE specification is stable now in release 8. To meet much higher requirements than release 8, 3GPP has initiated the LTE-A (LTE-Advanced) study item. In LTE-A, CoMP (coordinated multiple point transmission and reception) and CA (carrier aggregation) are two new features. CoMP is used to improve coverage and to increase cell-edge throughput. It is considered as an effective approach for ICIC...
Four utility-based criteria are considered to study dynamic resource allocation in Multiple Input Multiple Output - Orthogonal Frequency Division Multiple Access (MIMO-OFDMA) multiuser cellular systems. In these criteria, two generalized bargaining strategies, GNBS and KSBS, are used to emphasize different levels of user fairness, while the criteria of utilitarian and egalitarian are briefly discussed...
As the number of users increases, the amount of required feedback Channel State Information (CSI) at the base station becomes huge and prohibits the feasibility of conventional adaptive resource allocation algorithms in fairness-aware downlink OFDMA systems. Thus, this paper presents a novel mechanism making use of multi-user diversity to greatly reduce the feedback CSI while maintaining almost the...
Power allocation with relay selection with incomplete channel state information is considered. Particularly, the utility function is based on the rate and adds the different pricing schemes to reflect the cost of each node according to the different status of each node. We decide if and which relay node to take part in cooperative communication based on the SNR of each node. Then the source and the...
We consider the problem of secure communication in wireless fading channels in the presence of non-colluding passive eavesdroppers. The transmitter has multiple antennas and is able to simultaneously transmit an information bearing signal to the intended receiver and artificial noise to the eavesdroppers. We obtain an analytical closed-form lower bound for secrecy capacity, which is used as the objective...
This paper considers power allocation in spatially-correlated dual-hop multiple-input multiple-output (MIMO) relay channels under power constraint for each hop channel. The proposed scheme allocates the transmit power considering the spatial correlation as well as the average signal-to-noise ratio (SNR) of dual-hop MIMO relay channels. By means of upper-bound analysis, the proposed scheme can minimize...
In this paper, we propose a block-based OFDM decode-and-forward relaying scheme for cooperative wireless networks. In the scheme, an OFDM symbol is divided into blocks and one relay is selected for each block. Theoretical outage performance is analyzed and evaluated, and a unified outage expression is developed for our scheme and the other two schemes. Monte Carlo simulations are carried out to validate...
Resources allocation of OFDM system is a key factor that affects system performance. Parteek Bansal proposed a bit-power allocation algorithm under different bit error rate (BER). But the process of its bit allocation will cause high complexity and bad real-time to build a power-increment table. In this paper, a low-complexity multi-user subcarrier-bit-power allocation algorithm for wireless OFDMA...
For maximizing the benefit of network coding in two-way relay networks, the data rate of links from sources to a relay should be the same, since only the same number of received bits can be network-coded at a given time and the rate for broadcast at the relay is limited by the minimum rate over all links. Therefore, we investigate rate control scheme based on power control to maintain the link to...
In this paper, a new resource allocation scheme is proposed for a two-way OFDM relay network. In the proposed scheme, two terminals exchange information with the help of multiple relays, and subcarriers and their power are successively allocated to the relays to maximize sum capacity. To achieve fairness for the relays, power constraint on each relay is imposed. Simulation results show that the proposed...
This paper investigates the properties of social choice functions, that represent resource allocation strategies in interference coupled wireless systems. The resources can be physical layer parameters such as power vectors or antenna weights. The paper investigates the permissible social choice functions, which can be implemented by a mechanism in either Nash equilibria or dominant strategy - for...
Uncoordinated deployment of eNBs in local area environments will benefit from having support for dynamic frequency re-use mechanisms also known as "autonomous component carrier selection", where each eNB dynamically selects to use only a subset of the available component carriers (i.e. using from one component carrier up to the maximum number of available component carriers). Component carriers...
In this paper, we present a novel power allocation scheme for amplify and forward incremental relaying (IR) systems with the aim to minimize the overall outage probability at the destination. In our problem formulation, we take into account the outage-dependent activation of the relay when writing the power constraint. We provide a simple closed-form solution to the IR power allocation problem that...
The two-way relay channel (TWRC) describes the communication between two terminals sharing a common relay. In this work we compare different protocols for the TWRC with a half-duplex relay (forwarding and protocol I) and transmission schemes (network coding relaying with random binning and XOR precoding), when the relay works in decode-and-forward and without channel state information at the transmitters...
A two-way relaying system using the physical-layer network coding (PNC) does not cause the spectral loss induced by the half-duplex signaling. Furthermore, when the total power, which is limited, is properly distributed to transmission nodes in such a system, the system capacity will be enhanced significantly. In this paper, we propose an optimal power allocation in the two- way relay channel employing...
Cooperative networks have been appreciated for their spatial diversity benefits in wireless communications. In this paper, we will explore the error performance of cooperative networks depending on the relay locations. Both decode-and-forward (DF) and amplify-and-forward (AF) relaying protocols are considered with an arbitrary number of relays. To provide simple transceiver structure, differential...
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