Transcript Document
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) Primary users PT PR PT PR Primary users CT Secondary users CR Secondary users Approach: Use MIMO technology and optimize the parameters in the cooperative relay/transmission Approach - continue 3. Cooperatively limit the interference towards primary users. Ptx1 Prx2 Ptx2 Prx1 Stx2 Null constraints Null constraints Srx1 Stx1 Null constraint Srx2 Ptx: primary Tx Prx: primary Rx Stx: secondary Tx Srx: secondary Rx Evaluation and Results Evaluation (1) Numerical analysis Energy model: (4D) 2 E (mt, mr) (1 )e(b,mt, mr) M l N f Pc (mt, mr), G t Gr 2 (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) Primary users PT Secondary users PR 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) PT PR Primary users CT Secondary users CR Experiment and Results 1. Hardware and Software Architecture • Hardware: Universal Software Radio Peripheral + RFX 2400 daughter board • Software: GNUradio 2. Relay Strategy: Decode and Forward R S D Signal Combination 3. Programming Strategy • Python codes for data transmission and receiving • Visual programming for signal combination and performance evaluation 4. One relay node scheme • Two-phase implementation • Hardware setup • Results: Trial Combined 1 2 3 Average 2.21% 2.27% 2.89% 2.46% SourceDestination 9.13% 12.73% 10.76% 10.87% SourceRelay 15.73% 14.74% 23.69% 18.05% RelayDestination 7.05% 8.20% 8.75% 8.00% 5. Two-relay nodes scheme (in progress) • Implementation approach D S R1 Signal Combination R1 D D R1 R1 R2 R2 R2 R1 R1 R2 D Signal Combination