Presented by Mohamad Haidar, Ph.D. May 13, 2009 Moncton, NB, Canada Power Management and Bandwidth Allocation in a Cognitive Wireless Mesh Network Presented by Mohamad Haidar, Ph.D. May 13, 2009 Moncton, NB, Canada

Table of Content Introduction Problem statement Proposed Approach Problem Formulation Parameters and Assumptions Simulation Results Conclusion 12/4/2018

Introduction Cognitive Radio: It is a transceiver device that is able to understand and react to its operating environment. It is aware of channel conditions and activity. It changes its operating parameters to enable reliable, interference free, communications. 12/4/2018

Problem Statement Measurements consistently show that some bands are under-utilized in some areas at some times. Careful consideration should be given to the Primary User (PU) in order not to induce additional interference. 12/4/2018

Proposed Approach Heuristic algorithm: Sort Secondary Users (SUs) in ascending order according to highest BW request. This could be justified as giving a higher priority to SUs with high BW requests (Video and Voice vs. Data) Add SUs to the licensed spectrum as long as the interference level at the PU does not exceed a pre-defined threshold value and BW requests of SUs do not exceed the PU BW. In order to allow spectrum efficiency, power transmitted at SUs is dropped down as long as the data rate communication is still supported for the communication link between any two SUs. 12/4/2018

Problem Formulation NLIP Model: 12/4/2018

Parameters and Assumptions Locations of SUs and PUs are known. Communication activities between SUs are known. SUs operate on 2.4 GHz and PU operate on 700 MHz. Centralized infrastructure: The algorithm is run at the central server and decisions are multicast to intended SUs in order to instruct them about their respective frequencies or channels (along with the BW allocation on the licensed spectrum), and their transmitted power levels. Average data rate requests of each SU is known from which BW request can be calculated from the Shannon-Hartley theorem. Exchange of control information and signaling between SU nodes is beyond the scope at this moment. Information about the existence of the PU at the particular frequency and time is already known. SUs are assumed to be equipped with dual-antenna. Smooth switching between one antenna and the other. 12/4/2018

Results Scenario 1 Tx Power at all SU nodes and PU = 20 dBm PU BW = 12 MHz Interference threshold is -80 dBm SU Transmitter/Receiver Number SU Transmitter Power (dBm) SU Bandwidth Request (MHz) 3 / 1 8 2 14 / 13 1.9 13 / 11 11 1.8 1 / 16 6 0.4 tolerated interference at the PU is -80.57 dBm < -80 dBm BW Utilization ≈ 50% 12/4/2018

Results (cont’d) Scenario 2 SU Transmitter/Receiver Number SU Transmitter Power (dBm) SU Bandwidth Request (MHz) 12 / 7 3 4.80 14 / 13 4.10 13 / 11 7 3.00 tolerated interference at the PU is -82.36 dBm < -80 dBm BW Utilization ≈ 99.5% 12/4/2018

Results (cont’d) 12/4/2018

Conclusion and Future Work power management and spectrum utilization algorithm has been presented to allow SUs to opportunistically access the licensed spectrum. Future work: Control information and signalling Mobility of SUs Distributed approach rather than a centralized one. 12/4/2018