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Fourth generation (4G) and beyond-4G wireless standards must support sub-1Gbps data rates with peak bandwidth efficiencies of up to 30 bit/s/Hz. It is widely recognized that the use of multiple antennas on both ends of the wireless link, commonly referred to as MIMO, is the technology that will make this a reality. The problem is that most existing MIMO algorithms are either too complex to be able...
We introduce a technique to achieve dirty paper coding (DPC) capacity asymptotically with minimum feedback required reported to date in literature. Our approach called opportunistic interference management, is based on a new multiuser diversity scheme designed for wireless cellular networks. When there are K antennas at the base station with M mobile users in the cell, the proposed technique only...
Cooperative communications leverages the spatial diversity available in a wireless network enabling multiple radio nodes work together to improve the overall system performance. When a destination receiver combines the signal from an originating source with the associated signals from relay nodes, significant improvements in the bit error rate performance can be achieved. This paper details the measured...
In this paper, we consider the interference-mitigation based cognitive radio (CR) model where the CR and primary users can coexist at the same time and frequency bands, under the constraint that the primary rate remains the same with the single-user decoder. To meet such a coexistence constraint, the unidirectional cooperation from the CR user is performed by relaying the primary user's signal. We...
We1 consider transmission over a set of parallel MARCs (multiple-access relay channel) based on the OFDM (Orthogonal Frequency Division Multiplexing) modulation. Two users communicate to a common destination (D) with the help of a relay (R) over a set of parallel channels. The relay operates in decode and forward (repetition coding type) and half duplex modes. The problem considered is the maximization...
A signal space diversity (SSD) scheme combined with Alamouti coding is investigated to achieve more diversity gain in fading channels. By approximating noise as a Gaussian distribution after Alamouti decoding, an exact expression for the SER for SSD schemes with Alamouti coding in Rayleigh fading channels can be derived for 4-QAM and 16-QAM. Using the formula derived by using upper bound approach,...
We analyze a medium access control (MAC)-free ??alternating sets?? transmission strategy for a two-dimensional strip-shaped network. This may be viewed as a broadcast strategy if the entire network has a strip shape, or it may be viewed as a unicast strategy if there is a set of pre-designated cooperators along a conventional multi-hop route, which we refer to as a cooperative route. When there are...
This paper proposes a structure that combines iterative equalization and turbo decoding, denoted as spatial turbo coding (STC), for single carrier signaling to achieve near capacity performance in multipath-rich fading channels. Instead of multiplexing the encoded bits in the time domain as in the standard turbo codes, the proposed STC transmits coded bits in the space domain by employing multiple-input...
As fading due to multipath propagation is an important issue in wireless systems, diversity techniques are employed in order to reduce the multipath fading effect. Cooperative communication represents a new class of diversity schemes in which multiple nodes equipped with a single antenna cooperate to generate a virtual multiple-antenna transmission system and thus offer the benefits of spatial diversity...
In this work, we present two high-rate quasi-orthogonal space-time coding (STC) schemes for three and four transmit antennas which are designed in conjunction with the serial interference cancellation (SIC) based receiver. The symbols of the proposed STCs are of judiciously designed diversity order which can be effectively exploited by the SIC based receiver to cancel interference as well as to obtain...
Cooperative diversity networks have been receiving a lot of attention recently as an attractive way to combat frequency-selectivity of wireless channel, as it consumes neither time nor frequency resources. In the conventional cooperative strategies, relays employ either a decode-and-forward (DF) or an amplify-and-forward (AF) relaying protocol. In this paper, we investigate a new hybrid cooperative...
Cooperative diversity techniques make a reduction in spectral efficiency despite of an increase in reliability. In this paper we propose a novel relaying protocol in a cooperative network with decode and forward (DF) relays to improve the spectral efficiency in addition to achieving full diversity order (maximum available reliability). The proposed protocol keeps the transmission rate fixed to the...
In this paper, we investigate the location optimization for decode-and-forward (DF) opportunistic cooperative networks, in which the impact of the availability of the direct link between the source and the destination has been studied. Under Rayleigh fading channels, the closed-form solution for the optimal location is derived. It is interesting to find that the optimal relay location is related to...
Cooperative relaying technique has shown potential in enhancing coverage area and reliability of transmission by forming virtual arrays. Opportunistic relaying tries to utilize best available channel between source and destination. Outage performance of relay based system can be improved through proper allocation of power and positioning of relay node. Analytical expression for outage probability...
This paper presents the implementation result of List-of-2 soft-decision Viterbi decoder on FPGA platform. It was to be used as the inner decoder of a special designed concatenated code, of which the outer decoder is Vector Symbol Decoder (VSD). Since list-of-2 Viterbi was not the final decoding stage, it was not required to provide low decoding failure probability. Therefore, only a small list of...
This paper presents a new coded cooperation scheme based on Reed Solomon code. The new scheme offers transmission security since the second frame of the partitioned data contains only partial of the parity check data. A new algorithm for handling the choice of cooperation level between the users is also developed. Simulation results of the new scheme over multipath Rayleigh fading channels show around...
Alamouti scheme provides a diversity gain no more than 2 over time-selective fading channels under the circumstances of 2??1 MIMO. A full-rate space-time code, space-time codes for time-selective fading (STC-TS), is proposed to provide more diversity gain when the channels fade fast. While the transmission lasts 2N (N>1) symbol periods, the diversity gain is almost 2N. What's more, the optimization...
Cooperative-diversity networks have recently been proposed as an effective technique to form virtual antenna arrays without using collocated multiple antennas. In this paper, we consider the adaptive decode-and-forward (DF) cooperative-diversity system with the Nth best-relay selection scheme. In the best-relay selection scheme, from the set of M relays the best relay only forwards the source signal...
In this paper, we analyze the performance of cooperative diversity wireless networks using amplify-and-forward (AF) or decode-and-forward (DF) relaying over independent, non-identically distributed Nakagami-m fading channels. We derive the symbol error probability (SEP) using the moment generating function (MGF) of the end-to-end signal-to-noise-ratio (SNR) at the destination. In AF relaying, and...
This paper analyzes a cooperative diversity scheme in which multiple (i.e., more than two) source nodes cooperate to deliver their packets to a common destination. To obtain spatial diversity, the source nodes form a partnership that enables each source node to transmit its own packets while relaying those of its partners. Instead of time-multiplexing the codewords for local packets and relay packets...
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