04-04-2015, 03:56 PM
space division multiple access seminars report pdf
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space division multiple access seminars report pdf
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space division multiple access seminars report pdf
11-04-2017, 11:51 AM
Spatial division multiple access (SDMA) is a channel access method based on the creation of parallel spatial tubes along with larger capacity pipes by spatial multiplexing and / or diversity, so it is able to offer a Superior performance in radio multiple access communications In traditional mobile cellular network systems, the base station has no information on the position of the mobile units within the cell and radiates the signal in all directions within the cell to provide coverage Of radio. This results in the waste of energy in the transmissions when there are no mobile units to reach, in addition to causing interference to the adjacent cells using the same frequency, the so-called co-channel cells. Similarly, at reception, the antenna receives signals from all directions including noise and interference signals. By using intelligent antenna technology and different spatial locations of mobile units within the cell, spatial division multiple access techniques offer attractive performance improvements. The radiation pattern of the base station, both in transmission and reception, is adapted to each user to obtain the highest gain in the direction of that user. This is often done using phased array techniques.
In GSM cellular networks, the base station is aware of the distance (but not the address) of a mobile phone by using a technique called "synchronization advance" (TA). The base transceiver station (BTS) can determine to what extent the mobile station (MS) is interpreting the notified TA. This information, along with other parameters, can then be used to shut down the BTS or MS, if a power control function is implemented in the network. Power control in BTS or MS is implemented in most modern networks, especially in MS, as this ensures a better battery life for MS. This is also why having a BTS near the user results in less exposure to electromagnetic radiation. This is why one can be safer to have a BTS near them as their MS will shut down as much as possible. For example, there is more power being transmitted from the MS than what would be received from the BTS, even if they were within 6 feet of a BTS mast. However, this estimate might not consider all mobile stations that a particular BTS is supporting with EM radiation at any given time.
In the same way, 5th generation mobile networks will focus on the use of the given position of the MS in relation to BTS in order to focus all the radio frequency power MS to the BTS direction and vice versa, thus allowing energy savings For the Mobile Operator by reducing the MS SAR rate by reducing the EM field around the base stations since the beam formation will concentrate the RF energy when it will be used instead of propagating evenly around the BTS, reducing health problems And safety.
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