Cornel Zlibut, Undergraduate Junior Tennessee State University Cooperative Wireless Communication and Networked Methods for Spectrum Sharing and Interference 14 – 17 November 2011 Presented by Dr. Wei Chen, Professor Cornel Zlibut, Undergraduate Junior Tennessee State University

Problem Statement Study the benefits that the cooperation brings to cognitive radio networks. Focus on the cooperative MIMO technology, where multiple distributed secondary users cooperate on data transmission and reception. Goal: Design of novel cooperative paradigms that can significantly improve the performance of both overlay and underlay systems in cognitive radio networks.

Approach 1. Cooperative Relay in Overlay System Multiple secondary users help primary users’ data transmission (in order to use the primary users channel) 2. Cooperative Transmission in Underlay Systems Multiple secondary users cooperate on data transmission (in order to reduce the energy level without disturbing the primary users transmission) PR Primary users PT Secondary users Primary users Secondary users PT PR CT CR Approach: Use MIMO technology and optimize the parameters in the cooperative relay/transmission

Approach - continue 3. Cooperatively limit the interference towards primary users. Ptx: primary Tx Prx: primary Rx Stx: secondary Tx Srx: secondary Rx Ptx1 Prx1 Ptx2 Prx2 Stx1 Srx1 Stx2 Srx2 Null constraints Null constraint

Evaluation and Results Numerical analysis Energy model: (2) Experiment on Universal prototype testbed

Evaluation and Results - continue 1. Cooperative Relay in Overlay System Multiple secondary users help primary users’ data transmission (in order to use the primary users channel) PR Primary users PT Secondary users

Evaluation and Results - continue 2. Cooperative Transmission in Underlay Systems Multiple secondary users cooperate on data transmission (in order to reduce the energy level without disturbing the primary users transmission) Primary users Secondary users PT PR CT CR

Experiment and Results Hardware and Software Architecture Hardware: Universal Software Radio Peripheral + RFX 2400 daughter board Software: GNUradio Relay Strategy: Decode and Forward Programming Strategy Python codes for data transmission and receiving Visual programming for signal combination and performance evaluation S R D Signal Combination If this project is a continuation of previous work, under MLP, it is acceptable to use a couple of slides under the “Problem Statement” to discuss the previous work. The overall time limit still applies.

Two-phase implementation One relay node scheme Two-phase implementation Hardware setup Results: Trial Combined Source-Destination Source- Relay Relay-Destination 1 2.21% 9.13% 15.73% 7.05% 2 2.27% 12.73% 14.74% 8.20% 3 2.89% 10.76% 23.69% 8.75% Average 2.46% 10.87% 18.05% 8.00%

Two-relay nodes scheme (in progress) Implementation approach Signal Combination S D R1 R2 R1 R2 R1 R2 D R1 R2 D R1 D R1 Signal Combination If this project is a continuation of previous work, under MLP, it is acceptable to use a couple of slides under the “Problem Statement” to discuss the previous work. The overall time limit still applies.