![ The capacity increase can be seen by comparing MEMO
systems with SISO, SIMO, and MISO systems
◦ SISO:capacity is given by Shannon’s classical formula:
Where B is the BW and h is the fading gain
◦ SIMO (with M transmitting antennas), the capacity is given by
[2]
◦ MISO (with M transmitting antennas), the capacity is given by
[2]
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N=1 M=1 N=2 M=1 N=1 M=2 N=2 M=2 N=2 M=4 N=2 M=6 N=4 M=4 N=8 M=8](https://image.slidesharecdn.com/ecemimoppt-200611053903/85/Ece-mimo-ppt-17-320.jpg)
Ece mimo ppt
- 1. EC6801 WIRELESS COMMUNICATION SYLLABUS UNIT I WIRELESS CHANNELS Large scale path loss – Path loss models: Free Space and Two-Ray models -Link Budget design – Small scale fading- Parameters of mobile multipath channels – Time dispersion parameters Coherence bandwidth – Doppler spread & Coherence time, Fading due to Multipath time delay spread – flat fading – frequency selective fading – Fading due to Doppler spread – fast fading – slow fading. UNIT II CELLULAR ARCHITECTURE Multiple Access techniques - FDMA, TDMA, CDMA – Capacity calculations–Cellular concept Frequency reuse - channel assignment- hand off- interference & system capacity- trunking & grade of service – Coverage and capacity improvement. UNIT III DIGITAL SIGNALING FOR FADING CHANNELS Structure of a wireless communication link, Principles of Offset-QPSK, p/4-DQPSK, Minimum Shift Keying, Gaussian Minimum Shift Keying, Error performance in fading channels, OFDM principle – Cyclic prefix, Windowing, PAPR. UNIT IV MULTIPATH MITIGATION TECHNIQUES Equalisation – Adaptive equalization, Linear and Non-Linear equalization, Zero forcing and LMS Algorithms. Diversity – Micro and Macrodiversity, Diversity combining techniques, Error probability in fading channels with diversity reception, Rake receiver, UNIT V MULTIPLE ANTENNA TECHNIQUES MIMO systems – spatial multiplexing -System model -Pre-coding - Beam forming - transmitter diversity, receiver diversity- Channel state information-capacity in fading and non-fading channels
- 2. EC 6801 WIRELESS COMMUNICATION FIREST AND SECOND UNIT STUDY PROBLEMS ALSO Unit I 1. Explain the time variant two-path model of a wireless propagation channel. 2. What is small scale fading? Explain the classification of wireless channels using multipath delay spread and Doppler Spread. 3. Assume a receiver is located 10km from a 50W transmitter. If the carrier frequency is 1900MHz, Gt =l,Gr=2, find the power at the receiver assuming a free space propagation. Also determine the received power at the mobile using two ray ground reflection model considering the transmitter antenna height as 50m, receive antenna height as 1.5m above the ground and the ground reflection as – 1 4. Explain with mathematical equations two-ray path loss model. 5. Explain free space propagation model and derive the FRISS free space equation gain expression
- 3. Unit II 1. Explain FDMA, TDMA and CDMA multiple access schemes 2. Discuss about the different types of interferences in wireless communication and ho it can be minimized 3. With diagram explain a handoff (or) handover scenario at cell boundary. Compa different types of handoff techniques 4. Explain the methods of increasing the capacity of wireless cellular networks. 5. A spectrum of 30 MHz is allocated to a wireless FDD cellular system whichuses two kHz simplex channels to provide full duplex voice and control channels, compute th number of channels available per cell if a system uses (a) four cell reuse (b) seven ce reuse (c) 12-cell reuse. If 1 MHz of the allocated spectrum is dedicated to contr channels, determine an equitable distribution of control channels and voice channe in each cell for each of the three systems. 6. A mobile is located 2 km away from a base station and uses a vertical / 4 monopo antenna with a gain of 2.55 dB to receive cellular radio signals. The E field at 1 k from transmitter is measured to be 10-3 V/m. The carrier frequency used for th system is 900 MHz. Determine the length and effective aperture of the receivin antenna. Also, find the received power at the mobile using the two-ray groun reflection model assuming the height of the transmitting antenna is 50 m and th receiving antenna is 1.5 m above ground. 7. If a signal to interference ratio of 20dB is required for satisfactory forward chann performance of a cellular system, what is the frequency reuse factor and cluster si that should be used for maximum capacity if the path loss exponent is a) n = 4 b) n =3 Assume that there are 3 co-channel cells in the first tier and all of them are at the sam distance from the mobile.
- 4. Unit III 1. Explain pi/4 QPSK , Offset QPSK and DQPSK with transmitter and receiver diagrams comment on spectral efficiency 2.What is MSK? Explain with suitable diagrams the transmitter and receiver for MSK modulation scheme. 3.Explain in detail about Gaussian Minimum Shift Keying (GMSK) Transmitter and receiver with 4. Draw the basic arrangement of Orthogonal Frequency Division Multiplexing transceivers and discuss its overall operation 5.A 900 MHz carrier signal is frequency modulated using a 100 kHz sinusoidal modulating waveform. The peak deviation of the FM signal is 500 kHz. If this FM signal is received by a superheterodyne receiver having an IF frequency of 5 MHz, determine the IF bandwidth necessary to pass the signal 6.A zero mean sinusoidal message is applied to a transmitter that radiates an AM signal with 10 kW power. Compute the carrier power if the modulation index is 0.6. What percentage of the total power is in the carrier? Calculate the power in each sideband.
- 5. Unit IV 1. Explain (a)Spatial diversity (b), Temporal Diversity (c).Polarizationdiversity (d).Macro diversity 2. Examine about the effects of multipath propagation on CDMA 3. With a neat block diagram, explain RAKE Receiver 4. Explain the operation an adaptive equalizer at the receiver side 5. discuss the decision feedback equalization 6. With diagram, explain Adaptive equalization techniques. Explain Least Mean Square (LMS) algorithm and Recursive LeastSquares (RLS) algorithmin detail
- 6. Unit V 1. With diagram, explain the system model for MIMO systems 2. Discuss about the operation of Spatial Multiplexing systems. 3. Derive the capacity of Non fading channel for information transmitted from a wireless system 4. Derive the capacity of a fading channel for information transmitted from a wireles system using waterfilling algorithm Explain the operation of transmit precoding and receiver precoding schemes
- 7. Introduction What is MIMO? Spatial Diversity and Spatial Multiplexing MEMO capacity on fading channels Benefits of MIMO Drawbacks of MIMO Conclusion
- 8. MIMO Systems: use multiple inputs and multiple outputs from a single channel are defined by Spatial Diversity and Spatial Multiplexing
- 9. As we know MIMO is multiple antenna technology in which more than one antennas are used at transmitter and receiver stations.
- 10. Spatial Diversity ◦ Signal copies are transferred from multiple antennas or received at more than one antenna ◦ redundancy is provided by employing an array of antennas, with a minimum separation of λ/2 between neighbouring antennas Spatial Multiplexing ◦ the system is able to carry more than one data stream over one frequency, simultaneously
- 11. There is always a need for increase in performance in wireless systems ◦ Significant increase in spectral efficiency and data rates ◦ High Quality of Service (QoS) ◦ Wide coverage, etc. Wireless channel that we are using is very unfriendly ◦ Suffers from Co–channel interference and signal level fading ◦ It provides a limited bandwidth ◦ power falls off with distance
- 12. By using Multiple Output Multiple Input (MIMO) systems ◦ Diversity gain mitigates the fading and increases coverage and improves QoS ◦ Multiplexing gain increases capacity and spectral efficiency with no additional power or bandwidth expenditure ◦ Array gain results in an increase in average receive SNR. Spatial Diversity and Spatial Multiplexing can be conflicting goals
- 13. MIMO channels can be decomposed into a number of R parallel independent channels → Multiplexing Gain ◦ Principle: Transmit independent data signals from different antennas to increase the throughput, capacity.
- 14. The capacity increase can be seen by comparing MEMO systems with SISO, SIMO, and MISO systems ◦ SISO:capacity is given by Shannon’s classical formula: Where B is the BW and h is the fading gain ◦ SIMO (with M transmitting antennas), the capacity is given by [2] ◦ MISO (with M transmitting antennas), the capacity is given by [2] ) 2 1( 2 log hsnrBC ) 1 2 1( 2 log m n n hsnrBC ) 1 2 1( 2 log N n n h N snr BC
- 15. The capacity for MIMO systems can have the following forms (Assuming Tx antennas = Rx antennas = N): A) If the channel is not known at the transmitter: ◦ Where Es is the total power, σ2 is noise level of AWGN ◦ Hence the power is equally shared by each channel ◦ The capacity grows linearly with the number of antennas B) If the channel is known at the transmitter ) 2 2 1( 2 log n h N s E NC N n n hn E C 1 ) 2 2 1( 2 log
- 17. 0 5 10 15 20 25 30 35 40 45 50 55 60 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 SNR [dB] AverageCapacity[bits/sec/Hz] N=1 M=1 N=2 M=1 N=1 M=2 N=2 M=2 N=2 M=4 N=2 M=6 N=4 M=4 N=8 M=8
- 18. Improves the signal quality and achieves a higher SNR at the receiver-side Principle of diversity relies on the transmission of structured redundancy xi yi
- 20. ➨There is lower susceptibility of tapping by unauthorized persons due to multiple antennas and algorithms. ➨The systems with MIMO offers high QoS (Quality of Service) with increased spectral efficiency and data rates. ➨The wide coverage supported by MIMO system helps in supporting large number of subscribers per cell. ➨The MIMO based system is widely
- 21. ➨The hardware resources increase power requirements. Battery gets drain faster due to processing of complex and computationally intensive signal processing algorithms. This reduces battery lifetime of MIMO based devices. ➨MIMO based systems cost higher compare to single antenna based system due to increased hardware and advanced software requirements.
- 22. IEEE 802.11n/ad(WLAN) IEEE 802.16m(WIMAX) LTE(3GPP) VIDEO PROCESSING /AUDIO PROCESSING
- 23. The capacity of Receive or Transmit Diversity grows logarithmically with the number of antennas Capacity of MIMO increases linearly with the number of antennas Using Spatial Diversity: ◦ The SNR increases and decreases when using MIMO Spatial Multiplexing and Spatial Diversity are conflicting objectives