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PERFORMANCE ANALYSIS OF LMS BASED MIMO RELAY COMMUNICATION. Yamuna Dhungana Supervisor : Dr. R.M.A.P. Rajatheva May 16, 2011. Motivation. Goal of 4G wireless Network : to offer high data rate and high quality of service anytime, anywhere
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PERFORMANCE ANALYSIS OF LMS BASED MIMO RELAY COMMUNICATION Yamuna Dhungana Supervisor : Dr. R.M.A.P. Rajatheva May 16, 2011
Motivation • Goal of 4G wireless Network : to offer high data rate and high quality of service anytime, anywhere • Condition: Such network can cover any geographical area by either using terrestrial network or satellite network • Solution : Integration of terrestrial and satellite networks into a hybrid architecture forming Hybrid Satellite/Terrestrial Network This thesis proposes … terrestrial relay node assisted cooperative communication approach towards Hybrid Satellite/ Terrestrial network
Satellite Communication • voice, data, video and networking services through large, expensive, high-power earth stations communicating via geostationary satellites • provides services through low earth-orbit (LEO) and medium earth orbit (MEO) satellites directly communicating with lower power mobile user terminals • Works like terrestrial cellular communication Earth station (ES) Transmitter Traditional satellite communication Land mobile satellite (LMS) communication
Relay Assisted Cooperative communication R S D • a collaborative communication in which a relay station helps to forward information between source and destination • Major Relay protocols • Amplify and Forward(AF) • Decode and Forward(DF) • Improves transmission reliability through diversity
Proposed System: Basic Model • Applies the concept of relay transmission to LMS communication • Implements through a terrestrial relay node forwarding information between satellite and land mobile user terminal • Develops a form of Hybrid Satellite/ Terrestrial Network
Advantages • Brings satellite coverage indoor or in tunnels • Can serve low cost user terminal with no satellite transmission/ reception capabilities Link not available due to heavy shadowing • Serves as spatial diversity technique in mitigating the blockage effect in LMS channels • Support terrestrial networks unable to provide their services (e.g., because of lack of coverage, emergency situations, network overloads)
Proposed System: Enhanced Model • The basic relaying concept in LMS communication is enhanced through the incorporation of multiple antennas at all the three terminals. Multiple input multiple output (MIMO) system Single Antenna System Transmitter . . . . Receiver • MIMO system offers • Enhanced throughput • Increased transmission • reliability . . . . • MIMO relaying technology • A new paradigm with tremendous potential • Already proposed as a next major extension of IEEE • 802.16 WiMAX
Satellite Channel Model • LMS communication suffers from strong variations of the received signal power due to signal shadowing and multipath fading. • Signal shadowing by obstacles in the propagation path (e.g. buildings, trees, etc.) results into attenuation of the signal power over the entire bandwidth. • Proper modeling of such phenomena is important for performance evaluation. • In this thesis, LMS link is modeled with Shadowed Rician fading model which accounts for both line-of-sight (LOS) random shadowing and multipath fading.
System configurations proposed for implementation Configuration I: Transmit Beamforming Receive Beamforming . . . . Source (S) Relay (R) Destination (D) . . . HSR hRD Nd Ns Nr Selected Antenna • The configuration is analyzed • Under both AF and DF relaying • Considering both uncorrelated and correlated antennas
Configuration II: 1 1 1 1 . . . Fixed gain Amplifier OSTBC encoder . . . . . . Noise whitening filter . . . OSTBC decoder H1 H2 Nr Nr Ns Nd Terrestrial Relay node (R) Satellite (S) Mobile Station (D)
Results and Discussions: Configuration I Average SER of AF and DF system using QPSK modulation for antenna configuration (Ns,Nr,Nd) Average SER of AF system for antenna configuration (Ns,Nr,Nd) in different correlation scenarios
Results and Discussions: Configuration II Average SER of BPSK and 4PAM constellations using Alamouti’s coding for antenna configuration (Ns,Nr,Nd)
Summary • An approach to hybrid satellite/terrestrial network towards the achievement of ambitious coverage requirement of 4G networks is proposed. • The proposed concept is complemented with MIMO technology. • MIMO system is found to have significant performance gains over single input single antenna (SISO) system. • Two different system configurations are proposed for MIMO relaying concept implementation in LMS communication.
Future Research • Feasibility and performance analysis in multiple relay environment. • Assessment of advantages and drawbacks of relaying characteristics of infrastructure based fixed relays or mobile devices carried by subscribers.
List of Publications Conference Publication • Yamuna Dhungana and Nandana Rajatheva, “Analysis of LMS based dual hop MIMO systems with beamforming,” in Proc. IEEE Int. Conf. on Commun. (ICC2011), accepted for publication. Journal Publications • Yamuna Dhungana and Nandana Rajatheva, “Impact of antenna correlation on LMS based dual hop MIMO systems with beamforming,” IEEE Trans. Wireless Commun., submitted for publication. • Yamuna Dhungana and Nandana Rajatheva, “Dual Hop MIMO OSTBC for LMS Communication,” IEEE Commun. Letter., submitted for publication.
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