4 research outputs found
Rate adaptive resource allocation with fairness control for OFDMA networks
The use of opportunistic radio resource allocation techniques in order to efficiently manage the resources generates
a low fairness among the users in a cellular system due to uneven Quality of Service (QoS) distribution. Some classic rate adaptive policies tried to tackle this problem for OFDMA systems by
proposing solutions to maximize capacity, maximize fairness, or find a static trade-off between these two objectives. This
work generalizes these classic policies and propose a dynamic fairness/rate adaptive technique based on dynamic sub-carrier
assignment and equal power allocation that considers a new fairness constraint in the optimization problem. By means of
extensive system-level simulations, it is demonstrated that the
proposed technique is able to provide an instantaneous (short-term) fairness control, which provides to the network operator
the flexibility to operate on any desired trade-off point.Peer ReviewedPostprint (published version
Investigation on iterative multiuser detection physical layer network coding in two-way relay free-space optical links with turbulences and pointing errors
Physical layer network coding (PNC) improves the throughput in wireless networks by enabling two nodes to exchange information using a minimum number of time slots. The PNC technique is proposed for two-way relay channel free space optical (TWR-FSO) communications with the aim of maximizing the utilization of network resources. The multipair TWR-FSO is considered in this paper, where a single antenna on each pair seeks to communicate via a common receiver aperture at the relay. Therefore, chip interleaving is adopted as a technique to separate the different transmitted signals at the relay node to perform PNC mapping. Accordingly, this scheme relies on the iterative multiuser technique for detection of users at the receiver. The bit error rate (BER) performance of the proposed system is examined under the combined influences of atmospheric loss, turbulence-induced channel fading, and pointing errors (PEs). By adopting the joint PNC mapping with interleaving and multiuser detection techniques, the BER results show that the proposed scheme can achieve a significant performance improvement against the degrading effects of turbulences and PEs. It is also demonstrated that a larger number of simultaneous users can be supported with this new scheme in establishing a communication link between multiple pairs of nodes in two time slots, thereby improving the channel capacity