Performance and fairness enhancement in ZigBee networks

ZigBee is a robust wireless communication standard which is based on physical and MAC layer on IEEE 802.15.4. ZigBee is also critically limited by the low data rate standard when there are many source nodes in the network. How to fairly and efficiently access the network and delivery the packets should be considered as one of the crucial issues....

Allocation of Opportunistic Spectrum for Cognitive Radio Ad hoc Networks

Cognitive Radios (CRs) address the problems of spectrum scarcity and under-utilization of the spectrum. However, realizing a CR network is neither easy nor straight-forward. The link layer in CR Ad hoc Networks is responsible for allocating suitable channels, out of the currently available channels. It is also responsible for setting up...

Cognitive Radio in a Regulatory Environment

It has been widely recognized that the valuable, yet finite radio spectrum is being underutilized by licensed systems both spatially and temporally. To realize a more efficient use of this valuable resource, secondary spectrum usage by cognitive radios is being considered. Cognitive Radio is a paradigm for wireless communication in which either...

New upper bounds on the separating redundancy of linear block codes

Most decoding algorithms of linear codes, in general, are designed to correct or detect errors. However, many channels cause erasures in addition to errors. In principle, decoding over such channels can be accomplished by deleting the erased symbols and decoding the resulting vector with respect to a punctured code. For any given linear code and...