This document discusses a project analyzing the performance of MIMO-OFDM systems in Rayleigh fading channels. MIMO-OFDM is a popular technique for mobile communications that uses multiple antennas at the transmitter and receiver to improve data rates and capacity. The project compares the ergodic and outage capacities of MIMO-OFDM systems with varying numbers of transmit and receive antennas and analyzes performance metrics like SNR and BER. It aims to evaluate MIMO-OFDM prototype performance and investigate methods for cost reduction.

1. SUBMITTED BY
ABHISHEK PANDEY

2.  In this project we show the performance of MIMO-OFDM
system in Rayleigh Fading Channel
 MIMO-OFDM system is very popular technique for mobile
communication now a day’s .We compares Ergodic and
Outage Capacity , with taking various numbers of
Transmitting and Receiving antennas and various
performance measures such as SNR, BER etc.
 MIMO-OFDM, Ergodic Capacity, BER, SNR Outage Capacity

3.  Ever-increasing demands in communication industry
towards wireless
 Challenges:
- to improve spectral efficiency
- efficient bandwidth utilization
- economical Signal Processing
algorithms
- high speed processing h/w

4. - Multiple i/p multiple o/p
antenna array
- Used to increase data rates,
improve capacity and BER
(bit error rate) of the system
Diagram of a MIMO wireless transmission
system. - Typically used with OFDM so
as to suit best needs in next
generation comm. i.e. “4G”

5.  SU-MIMO (Single User - MIMO)
this utilizes MIMO technology to improve the
performance towards a single user.
 MU-MIMO (Multi User - MIMO)
this enables multiple users to be served through
the use of spatial multiplexing techniques.

6.  Definition
 The first OFDM schemes presented in 1966
 Development of OFDM over years

7. - Converts a frequency selective
channel into a parallel collection
of frequency flat sub channels
- Orthogonal frequency division
multiplexing uses bandwidth
efficiently
- Improves multipath fading issues
- Reduces the effect of ISI (inter-
sub carrier interference)
OFDM System block Diagram

8.  It distributes the data over a large number of carriers that
are spaced apart at precise frequencies.
 This spacing provides the "orthogonality" in this
technique which prevents the demodulators from seeing
frequencies other than their own.

9. ◦ Two conditions must be considered for the
orthogonality between the subcarriers.
 Each subcarrier has exactly an integer number of cycles in the
FFT interval.
 The number of cycles between adjacent subcarriers differs by
exactly one.

12.  STTD (space time transmit diversity)
 SM (spatial multiplexing)
 AMC (adaptive modulation & coding) with modulation techniques such as
QPSK, 16-QAM, 64-QAM
 H-ARQ (Hybrid automatic repeat request)
 Shared access and MAC (medium access control) used for scheduling
packet access with Qos

13.  Coupling MIMO and OFDM concepts to improve data rates in
downlink of wireless communication networks.
 Analyzing the performance and building a prototype of
Wireless WAN’S using MIMO-OFDM
 Use of adaptive loading algorithms such as Chows and
Compello’s.
 Employing SVD (singular value decomposition) method to
increase the performance incase of MIMO

14.  Survey, Implementation and performance analysis of existing MIMO
 Learning s/w and h/w
 Developing efficient algorithms
 Software synchronization development
 Various candidate coding and receiver strategies
 Identification of Equipment
 Implementation of prototype

15.  The results obtained from these tests indicate very good
performance for the MIMO-OFDM prototype.
 Concept is proving to be very robust in highly dispersive
channels
 Cost reduction is being investigated through various methods
 Simulation results show that at any given BER the adaptive
SISO system will be outperformed by the adaptive MIMO
system
 Other future work areas involve the improvement of MIMO
processing complexity and practical implementation issues.