Publication Date

Fall 2010

Degree Type


Degree Name

Master of Science (MS)


Electrical Engineering


Birsen Sirkeci-Mergen


Cooperative, MIMO, Multi-stage Relay Network, Relaying Strategies, Saturated Amplify-and-forward

Subject Areas

Electrical Engineering


Wireless channels suffer from severe inherent impairments and hence

reliable and high data rate wireless transmission is particularly challenging to

achieve. Fortunately, using multiple antennae improves performance in wireless

transmission by providing space diversity, spatial multiplexing, and power gains.

However, in wireless ad-hoc networks multiple antennae may not be acceptable

due to limitations in size, cost, and hardware complexity. As a result, cooperative

relaying strategies have attracted considerable attention because of their abilities

to take advantage of multi-antenna by using multiple single-antenna relays.

This study is to explore cooperative signaling for different relay networks,

such as multi-hop relay networks formed by multiple single-antenna relays and

multi-stage relay networks formed by multiple relaying stages with each stage

holding several single-antenna relays. The main contribution of this study is the

development of a new relaying scheme for networks using symbol-level

modulation, such as binary phase shift keying (BPSK) and quadrature phase shift

keying (QPSK). We also analyze effects of this newly developed scheme when it

is used with space-time coding in a multi-stage relay network. Simulation results

demonstrate that the new scheme outperforms previously proposed schemes:

amplify-and-forward (AF) scheme and decode-and-forward (DF) scheme.