Spatial multiplexing and Receive Diversity in Wimax Spatial multiplexing WiMAX also supports spatial multiplexing, where multiple independent streams are transmitted across multiple antennas. If the receiver also has multiple antennas, the streams can be separated out using space-time processing. Instead of increasing diversity, multiple antennas in this case are used to increase the data rate … Read more
Codeword, layer, and precoding in LTE Terms codeword, layer, and precoding have been taken to refer specifically to LTE signals and processing. The figure shows the processing steps to which they relate. The terms used in the following ways: Codeword: codeword represents the user data before it is formatted for transmission. One or two code … Read more
How and What Spatial Diversity Antenna Systems in GSM The spatial diversity antenna system is constructed by physically separating two receiving base station antennas. Here I write on spatial diversity antenna system criteria, configuration. SPATIAL DIVERSITY ANTENNA SYSTEMS Once they are separated far enough, both antennas receive independent fading signals. As a result, the signals … Read more
Diversity Reception: Multiple Antennas at Base Station Each Antenna is Affected by Multipath Differently Due to Their Different Location Allows Selection of the Signal Least Affected by Multipath Fading If Diversity Antennas are Good, Why Not Use Base Stations as a Diversity Network? – Soft Handoff The concept of diversity reception has been well known … Read more
Spatial Multiplexing In a multipath environment, the data rate increase due to MIMO is equal to the number of MIMO antennas. Rather than to transmit the same bit of more than two antennas, the Spatial Multiplexing method sends a data bit from the first antenna, and another bit of the second antenna at the same … Read more
Make use of a number of receive antennas that are well separated (coherence distance) to generate independent receptions of the transmitted signal. Selection diversity: choose received signal with largest received power, S/N, etc. Switched diversity: choose alternate antenna if signal falls below a certain threshold. Linear combining: linearly combine a weighted replica of all received … Read more
We know that we normally have several independent paths from TX to Rx of different lengths, these are affected and delayed differently, Signals that start out together at the transmitter will be separated in time when they reach the receiver Diversity doesn’t work with Line of Sight, This is exploiting Multipath rather than fighting it … Read more
Basically Diversity Antenna required because of Signal Rich at mobile or BTS by reflection and this change value of its level and quality either good or bed. Let’s understand in detail. NEED OF DIVERSITY In a typical cellular radio environment, the communication between the cell site and mobile is not by a direct radio path … Read more
Similar to any radio network, standard isolation would be required if equipment from different vendors are to be combined. Which including guard band, filtering as well as vertical/horizontal separation. In addition, indoor DAS (distributed antenna system) may contribute to interference problem particularly on the uplink due to PIM related inter-modulation, over drive of input RF … Read more