Performance improvements in SNR of a Multipath channel using OFDM-MIMO

The Non Line of Sight (NLOS) broadband wireless access provided by Worldwide Interoperability for Microwave Access (WiMAX) operating in 2-11 GHz frequency is susceptible to the effects of multipath propagation, diffraction fading, vegetation attenuation, shadowing loss etc. In order to overcome these effects effective fade mitigation techniques, have to be implemented. The Orthogonal Frequency Division Multiplexing- Multiple Input Multiple Output (OFDM-MIMO) is an efficient method that helps in combatting the fading and providing higher SNR to the WiMAX system. According to the IEEE 802.16 specification, for QPSK modulation, a threshold SNR of 6 dB is required for the link to operate. In the present work the use of OFDM-MIMO achieves a SNR above this operating threshold.

Performance improvements in SNR of a Multipath channel using OFDM-MIMO

The Non Line of Sight (NLOS) broadband wireless access provided by Worldwide Interoperability for Microwave Access (WiMAX) operating in 2-11 GHz frequency is susceptible to the effects of multipath propagation, diffraction fading, vegetation attenuation, shadowing loss etc. In order to overcome these effects effective fade mitigation techniques, have to be implemented. The Orthogonal Frequency Division Multiplexing- Multiple Input Multiple Output (OFDM-MIMO) is an efficient method that helps in combatting the fading and providing higher SNR to the WiMAX system. According to the IEEE 802.16 specification, for QPSK modulation, a threshold SNR of 6 dB is required for the link to operate. In the present work the use of OFDM-MIMO achieves a SNR above this operating threshold.

Performance Improvements in SNR of a Multipath Channel Using OFDM-MIMO

The Non Line of Sight (NLOS) broadband wireless access provided by Worldwide Interoperability for Microwave Access (WiMAX) operating in 2-11 GHz frequency is susceptible to the effects of multipath propagation, diffraction fading, vegetation attenuation, shadowing loss etc. In order to overcome these effects effective fade mitigation techniques, have to be implemented. The Orthogonal Frequency Division Multiplexing- Multiple Input Multiple Output (OFDM-MIMO) is an efficient method that helps in combatting the fading and providing higher SNR to the WiMAX system. According to the IEEE 802.16 specification, for QPSK modulation, a threshold SNR of 6 dB is required for the link to operate. In the present work the use of OFDM-MIMO achieves a SNR above this operating threshold

Use of cell-site diversity to mitigate rain attenuation in 10-66 GHz fixed WiMAX

The broadband wireless access system operating with a dominant Line-Of-Sight (LOS) component provides high receiver signal power and channel capacity. The fixed WiMAX LOS link requires inexpensive and less time consuming deployments and is easily scalable in accordance with the demand of the application. The focus of this paper is on the propagation impairments caused due to rain attenuation on the WiMAX technology and means of mitigating it. Rain attenuation is the major contributor of signal loss in a LOS set-up and Cell Site Diversity (CSD) technique is suitable for alleviating the losses incurred as a result of it. An experimental analysis of CSD was performed based on an extensive data set spanning over 4 years of Hydrological Radar Experiment (HYREX) rain gauge network. The study was performed on frequencies extending from 20 GHz to 54 GHz. This led to the observation that confirmed that the optimum angular separation is 180°, the point providing maximum CSD gain. Rain attenuation along diversity paths are strongly correlated at small azimuth angles. The CSD gain increases with increase in link distance and when links have equal link distances. A distance of about 6 km has been suggested as the maximum distance from the subscriber station to the base station