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
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
- Multiple i/p multiple o/p antenna array - Used to increase data rates, improve capacity and BER (bit error rate) of the systemDiagram of a MIMO wireless transmissionsystem. - Typically used with OFDM so as to suit best needs in next generation comm. i.e. “4G”
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.
Definition The first OFDM schemes presented in 1966 Development of OFDM over years
- 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
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.
◦ 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.
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
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
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
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.