2007 IEEE Wireless Communications and Networking Conference, 2007
We consider the problem of finding low-complexity, bandwidth-efficient, and processing-power effi... more We consider the problem of finding low-complexity, bandwidth-efficient, and processing-power efficient transmission schemes for a downlink scenario under the framework of diversity combining. Capitalizing on recent results for joint adaptive modulation and diversity combining schemes (AMDC), we design and analyze two AMDC schemes that utilize power control to reduce the radiated power, and thus the potential interference to other systems/users.
ABSTRACT We analyze two different approaches found in the literature for throughput maximization ... more ABSTRACT We analyze two different approaches found in the literature for throughput maximization of an adaptive transmission system operating over a slowly-varying flat-fading wireless channel with limited channel state information at the transmitter. While both approaches employ a finite number of transmission power levels and capacity-achieving codes, they differ in the number of quantization levels for the channel state, and whether or not information outage is allowed. Focusing on reliable data communications, we extend earlier works in a cross-layered fashion by adding an ARQ protocol, such that data received during such an outage can be retransmitted. We accurately analyze and compare the performance of the two approaches in terms of average spectral efficiency, probability of outage, and average feedback load, here defined in terms of the entropy of the feedback source. Numerical results show that, in general, there is a trade-off between the two approaches in terms of spectral efficiency and feedback load. However, scenarios in which one of the schemes can achieve a higher throughput at a lower feedback load are also identified.
2007 4th International Symposium on Wireless Communication Systems, 2007
We consider the joint application of power control, adaptive modulation and diversity combining i... more We consider the joint application of power control, adaptive modulation and diversity combining in the uplink of a two-cell wireless network. The goal is to derive a practical low-complexity, bandwidth-efficient, and battery-power efficient transmission scheme addressing the particular challenges of uplink transmission. Employing dynamic spectral reuse, we allow for coordination of the transmit power levels to minimize the sum transmit power, and thus implicitly the interference to co-existing systems and cells. Based on assumed transmitter knowledge of the channel fading, the proposed schemes adaptively select the signal constellation. We show that the novel scheme provides significant average transmit power reductions, yielding a substantial increase of battery lifetime, and decreased interference, while maintaining high average spectral efficiency, and compliance with bit error rate constraints.
2007 IEEE Wireless Communications and Networking Conference, 2007
We consider the problem of finding low-complexity, bandwidth-efficient, and processing-power effi... more We consider the problem of finding low-complexity, bandwidth-efficient, and processing-power efficient transmission schemes for a downlink scenario under the framework of diversity combining. Capitalizing on recent results for joint adaptive modulation and diversity combining schemes (AMDC), we design and analyze two AMDC schemes that utilize power control to reduce the radiated power, and thus the potential interference to other systems/users.
ABSTRACT We analyze two different approaches found in the literature for throughput maximization ... more ABSTRACT We analyze two different approaches found in the literature for throughput maximization of an adaptive transmission system operating over a slowly-varying flat-fading wireless channel with limited channel state information at the transmitter. While both approaches employ a finite number of transmission power levels and capacity-achieving codes, they differ in the number of quantization levels for the channel state, and whether or not information outage is allowed. Focusing on reliable data communications, we extend earlier works in a cross-layered fashion by adding an ARQ protocol, such that data received during such an outage can be retransmitted. We accurately analyze and compare the performance of the two approaches in terms of average spectral efficiency, probability of outage, and average feedback load, here defined in terms of the entropy of the feedback source. Numerical results show that, in general, there is a trade-off between the two approaches in terms of spectral efficiency and feedback load. However, scenarios in which one of the schemes can achieve a higher throughput at a lower feedback load are also identified.
2007 4th International Symposium on Wireless Communication Systems, 2007
We consider the joint application of power control, adaptive modulation and diversity combining i... more We consider the joint application of power control, adaptive modulation and diversity combining in the uplink of a two-cell wireless network. The goal is to derive a practical low-complexity, bandwidth-efficient, and battery-power efficient transmission scheme addressing the particular challenges of uplink transmission. Employing dynamic spectral reuse, we allow for coordination of the transmit power levels to minimize the sum transmit power, and thus implicitly the interference to co-existing systems and cells. Based on assumed transmitter knowledge of the channel fading, the proposed schemes adaptively select the signal constellation. We show that the novel scheme provides significant average transmit power reductions, yielding a substantial increase of battery lifetime, and decreased interference, while maintaining high average spectral efficiency, and compliance with bit error rate constraints.
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Papers by A. Gjendemsjo