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

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)

S

R

D

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

Demonstration of relaying concept in LMS communication

Advantages Brings satellite coverage indoor

or in tunnels

Link not available due to heavy shadowing

Can serve low cost user terminal with no satellite transmission/ reception capabilities

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.

Transmitter

.

.Receiver.

.

.

.

.

.

Single Antenna SystemMultiple input multiple output (MIMO) system

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 implementationConfiguration I:

Source(S)

.

.

.Relay

(R)

.

.Destination

(D)

.

.

TransmitBeamforming

ReceiveBeamforming

Ns NrNd

Selected Antenna

HSR hRD

The configuration is analyzed Under both AF and DF relaying Considering both uncorrelated and correlated antennas

Configuration II:

OSTBCencoder

Fixed gain

AmplifierOSTBC decoder

.

.

.

.

.

.

.

.

.

.

.

.H1 H2

Satellite(S)

Terrestrial Relay node(R)

1

Ns

1

Nr

1

Nr

1

Nd

Noise whitening

filter

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 PublicationsConference 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.

THANK YOU

ANY QUESTION ?