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In cooperative communications, relay usually forwards a full information of source data as received. Unlike this approach, this paper proposes a new relaying scheme based on multi-layered superposition coding with multiple antennas which forwards only partial information of superposed layer(s) on top of basic layer(s) of the source data. Fast forwarding of the partial information results in an increase in overall capacity. Simulation results are presented to show the superiority of the proposed scheme over full information relaying and direct transmission. [ABSTRACT FROM AUTHOR]

In this paper the objective is to enhance the spectral efficiency using combinations of transmit antenna selection with Linear Dispersion Code Selection. Both bit error rate minimization and throughput maximization criteria are here examined. The performance of the proposed spatial link adaptation scheme is evaluated under low mobility environments concluding that in case of linear receivers the transmit antenna code selection scheme with the combination of adaptive modulation and coding achieves a noticeable SNR gain (up to 3dB) in a large SNR margin (SNR from 6 to 18dB), which could be considered as a potent technique to achieve a smooth transition between diversity and multiplexing in order to maximize the overall system throughput. [ABSTRACT FROM AUTHOR]

System spectral efficiency and user fairness are crucial aspects for resource allocation in multi-user OFDM-based cellular networks. This work intends to investigate the influence of the performance of packet scheduling algorithms on the trade-off between these two objectives in scenarios with non real-time and real-time services. By means of system-level simulations, we were able to create a didactic map of the relation between these two aspects and propose ways to exploit this trade-off efficiently. [ABSTRACT FROM AUTHOR]

Originally developed for secure communications in military applications, frequency hopping systems possess anti-jamming and anti-interception features by exploiting time-frequency diversity over large spectrum. However, the spectral efficiency of existing FH systems is very low due to inappropriate use of the total available bandwidth. To improve the system capacity, in this paper, we propose an innovative message-driven frequency hopping (MDFH) scheme. Unlike in traditional FH systems where the hopping pattern of each user is determined by a pre-assigned pseudo-random (PN) sequence, in MDFH, part of the message stream will be acting as the the PN sequence for hopping frequency selection. Essentially, transmission of information through hopping frequency control introduces another dimension to the signal space, and the corresponding coding gain increases system efficiency by multiple times. The MDFH scheme can be further enhanced by allowing simultaneous transmissions over multiple frequency bands. Including both MDFH and OFDM as special cases, the enhanced MDFH scheme, named E-MDFH, can achieve higher spectral efficiency while providing excellent design flexibility. E-MDFH can readily be extended to a FH-based collision-free multiple access scheme. [ABSTRACT FROM AUTHOR]