TELE 9753 Advanced Wireless Communications
Tutorial 5 – Transmit Diversity
Question 1
Assuming average SNR of 10 dB on each link and threshold SNR of −5 dB, compare the outage probabilities of the following systems over Rayleigh fading channels:
1) a single-input/single-output system,
2) Alamouti scheme with two transmit antennas and a single receive antenna,
3) a single-input/multi-output system with MRC at two receive antennas, and
4) a multi-input/single-output system with transmit antenna selection (TAS) among 2 transmit antennas.
Question 2
Consider a multiple-input signle-output (MISO) system with two transmit antennas. The transmitters use Alamouti coding together with QPSK signaling, where the QPSK constellation is {1+j, −1+j, −1−j, 1−j}. If we received two signals as 1.3 + j1.2 and −0.1−j2.6, and the channels are given as h1 = 0.1 + j2 and h2 = −1.2 + j1.8, detect the transmitted message.
Homework 5
Requirements
1. Write down your full name, student number, and signature.
2. Detail the steps of your analysis/calculations/solutions. A single answer without derivations or expla nations is not acceptable.
3. Hand in a hard copy in the following class or a soft copy via Teams.
Question
Suppose that the Alamouti scheme is employed in the system with two transmit antennas and two receive antennas.
(a) Show that the scheme effectively provides two independent scalar channels.
(b) What is the gain of each channel ?
(c) Derive the expression for the instantaneous received SNR of such a system.