PPT 3.ppt final - report - 2011 - 1

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JOINT ESTIMATION OF I/Q IMBALANCE, CFO AND CHANNEL RESPONSE FOR MIMO OFDM SYSTEMS : 

JOINT ESTIMATION OF I/Q IMBALANCE, CFO AND CHANNEL RESPONSE FOR MIMO OFDM SYSTEMS Guided by Mrs. A.Vijayalakshmi, M.Tech., Presented by, Revathi.R II Yr, M.Tech (ECE)

OVERVIEW : 

OVERVIEW Introduction Proposed System Existing System MIMO Definition OFDM Concept System Model OFDM in MIMO Module Description Simulation Tool Results Conclusion Future Work References

INTRODUCTION : 

INTRODUCTION Normal modulation and multiplexing techniques are the basic systems in communication. From that usage of carrier and frequency each system differs.

EXISTING SYSTEM : 

Common OFDM system uses many carriers in that sense it differs from the normal modulation. EXISTING SYSTEM

Problem formulation : 

Problem formulation The I/Q imbalance and CFO without knowing the channel response so introduce the channel residual energy.

PROPOSED SYSTEM : 

PROPOSED SYSTEM The joint estimation of I/Q imbalance, CFO and channel response in MIMO OFDM systems. By introducing a new concept called channel residual energy (CRE) which proposes a new estimation method that needs only one OFDM block for training. By minimizing the CRE, we are able to estimate the I/Q imbalance and CFO without knowing the channel responses

Multiple Input and Multiple Output : 

Multiple Input and Multiple Output MIMO is the use of multiple antennas at both the transmitter and receiver to improve communication performance. APPLICATIONS: IEEE 802.11n (Wifi), 4G, 3GPP Long Term Evolution, WiMAX and HSPA+.

MIMO : 

MIMO

MIMO ADVANTAGES : 

MIMO ADVANTAGES MIMO provides Increase in rate Decrease in Pe (as a result of diversity, interference cancellation abilities etc) Resistively to fading (signal quality) Increased coverage Increased capacity Increased data rate Improved spectral efficiency Reduced power consumption Reduced cost of wireless network

OFDM DESIGN : 

OFDM DESIGN

OFDM DESIGN : 

OFDM DESIGN Generation of input signal Modulate the signal Calculate IFFT Addition of Cyclic prefix(cp) Transmit the signal Received signal with noise

OFDM SYMBOL : 

OFDM SYMBOL Nt =No of Transmitted antenna Nr =No of Received antenna M =No of channels L =channel length

ADVANTAGES : 

ADVANTAGES Bit error rate is maximized Inter carrier interference is minimized Only two training blocks required for estimation of CFO and I/Q Eliminates ISI and IFI through use of a cyclic prefix. Makes efficient use of spectrum by allowing the overlap

DISADVANTAGES : 

DISADVANTAGES The OFDM signal has a noise like amplitude with a very large dynamic range, therefore it requires RF power amplifiers with a high peak to average power ratio. It is more sensitive to carrier frequency offset and drift than single carrier systems are due to leakage of the DFT.

SYSTEM MODEL : 

SYSTEM MODEL OFDM design OFDM in MIMO Calculation of CRE Calculation of I/Q Estimation Of CFO Joint estimation of I/Q,CFO and channel response

OFDM IN MIMO : 

OFDM IN MIMO

CALCULATION OF CRE : 

CALCULATION OF CRE Channel Residual Energy(CRE) Channel Residual energy is the amount of energy present in a Channel at a particular time. This energy is reduced when the channel is engaged in a transmission or reception

USE MULTIPLE TRANSMIT AND MULTIPLE RECEIVE ANTENNAS FOR A SINGLE USER : 

USE MULTIPLE TRANSMIT AND MULTIPLE RECEIVE ANTENNAS FOR A SINGLE USER

MODULE : 

MODULE Estimate the MIMO channel Joint Estimation of Channel Response and I/Q Imbalance Joint Estimation of Channel Response and I/Q Imbalance and CFO Joint Estimation Using Two Repeated Training sequences

MODULE 1 : 

MODULE 1 In that module there are no CFO and I/Q imbalance. So for the purpose of channel estimation, we rewrite the received signal as R = HX + q Where H = complex channel gain X = transmission signal q= channel noise R = received signal

MODULE 2 : 

MODULE 2 In this module, we assume that there is no CFO. Hence we have = 0 and E = I. r is related to the received vector z as Alpha = I/Q mismatch parameter

MODULE 3 : 

MODULE 3 When the receiver suffers from both CFO and I/Q mismatch, the received vector z .If and are known, we can recover the desired baseband vector from z where E = diagonal matrix We can obtain an estimate of the MIMO channel response as From the above equation, when and are perfectly estimated, the last − entries of ˆd are again solely due to the channel noise

MODULE 4 : 

MODULE 4 The two repeated training sequences are available. That means the training block is a (+−1)×1 vector in the form of [CP x x ]. The training sequence x is an 2×1 vector, and the CP length is −1. This repeated structure has been proposed to solve the problem of CFO estimation. The repeated structure to solve the joint estimation of CFO, I/Q and channel response. Suppose that there are CFO and I/Q mismatch.

Slide 24: 

The two received 2 × 1 vectors are in the form of z = y + y∗ + q , z = y + ( y)∗ + q ,   where and are the OFDM block indexes and y is an 2 ×1 vector. Our goal is to jointly estimate CFO, I/Q and channel response from z and z. Below we will first show how to solve the two su bproblems: (A) given , estimate and (B) given , estimate and h(). Then the joint estimation of , and h() will be solved by a two-step approach

SIMULATION TOOL : 

SIMULATION TOOL MATLAB

IN & QUADRATURE PHASE : 

IN & QUADRATURE PHASE

CARRIER FREQUENCY OFFSET : 

CARRIER FREQUENCY OFFSET

CHANNEL RESPONSE : 

CHANNEL RESPONSE

CONCLUSION : 

CONCLUSION The new methods for the joint estimation of the I/Q imbalance, CFO and channel response for MIMO OFDM systems by using training sequences is proposed. Simulation results show that the MSEs of the proposed methods are very close to the CRB.

FUTURE WORK : 

FUTURE WORK Calculate CRE Values for different channels like Rayleigh channel and Richien channel Compare and analyze CRE value for choose the best channel for transmission

REFERENCES : 

REFERENCES Y.-H. Chung and S.-M. Phoong, “Joint estimation of I/Q imbalance andchannel response for MIMO OFDM system," in Proc. EUSIPCO, Sept.2007. Y. Tanabe, Y. Egashira, T. Aoki, and K. Sato, “Suitable MIMO-OFDMdecoders to compensate IQ imbalance," in Proc. IEEE WCNC, Mar.2007. K. Lee and J. Chun, “Frequency-offset estimation for MIMO andOFDM systems using orthogonal training sequences," IEEE Trans. Veh.Technol., Jan. 2007.

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