2 research outputs found
Distributed Energy Efficient Cross-layer Optimization for Multihop MIMO Cognitive Radio Networks with Primary User Rate Protection
Due to the unique physical-layer characteristics associated with MIMO and
cognitive radio (CR), the network performance is tightly coupled with
mechanisms at the physical, link, network, and transport layers. In this paper,
we consider an energy-efficient cross-layer optimization problem in multihop
MIMO CR networks. The objective is to balance the weighted network utility and
weighted power consumption of SU sessions, with a minimum PU transmission rate
constraint and SU power consumption constraints. However, this problem is
highly challenging due to the nonconvex PU rate constraint. We propose a
solution that features linearization-based alternative optimization method and
a heuristic primal recovery method. We further develop a distributed algorithm
to jointly optimize covariance matrix at each transmitting SU node, bandwidth
allocation at each SU link, rate control at each session source and
multihop/multi-path routing. Extensive simulation results demonstrate that the
performance of the proposed distributed algorithm is close to that of the
centralized algorithm, and the proposed framework provides an efficient way to
significantly save power consumption, while achieving the network utility very
close to that achieved with full power consumption.Comment: Submitted to IEEE Transactions on Vehicle Technolog
Coherent Communications in Self-Organizing Networks with Distributed Beamforming
Coherent communications aim to support higher data rates and extended
connectivity at lower power consumption compared with traditional
point-to-point transmissions. The typical setting of coherent communication
schemes is based on a single data stream with multiple transmitters and a
single receiver. This paper studies the case of multiple concurrent data
streams, each with multiple transmitters and multiple receivers, in
self-organizing wireless networks. A distributed optimization solution based on
joint network formation and beamforming is developed for coherent group
communications in a network of nodes that need to communicate over long
distances. This solution significantly improves the power gain for a single
data stream and the signal-to-interference-ratio for multiple data streams
compared to point-to-point communications. These gains are in turn translated
to improvements in communication range, power efficiency, reliability, and
throughput. In this multi-layer network optimization solution, nodes coordinate
with each other in a distributed manner to form transmitter and receiver
groups, and communicate with each other coherently over long distances. The
coherent beamforming protocol is optimized for given transmitter and receiver
groups, whereas the network formation protocol is optimized to determine these
groups. By using single-antenna communication nodes, the proposed optimization
solution provides a major gain in network communications and outperforms other
benchmark combinations of beamforming and network formation protocols