A Study On Antenna Hopping

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antenna hopping. In a system using antenna hopping, two or more transmit antennas are used interchangeably to achieve a diversity effect. Antenna hopping attracted attention from 1990s and comparatively in expansive way of achieving a transmit diversity gain in system such as GSM. The principle goal of MIMO technology is to improve either the quality (BER) or the data rate of the communication by means of adequate signal processing techniques at both ends of the system. The capacity can increase linearly with the number of antennas when using MIMO system. MIMO can obtain both multiplexing gain and diversity gain thus significantly increasing the system capacity as well as improving the reliability of the wireless link. Having high spectral…show more content…
STCs necessitate the transmission of multiple redundant copies of data so that there is possibility of receiving some copies of data through some are lost due to deep fading to enhance reliability of the data transmission. STCs are two types namely space–time trellis codes (STTCs) and space-time block codes (STBCs). STTC has been inaugurated as a coding technique that promises full diversity and considerable coding 5 gain but decoding complexity is very high. To avoid this, STBCs have been proposed by the effort work of Alamouti for transmit diversity and later Vahid Tarokh, Hamid Jafarkhani and Robert Calderbank made their contributions.[1-3]. This code gives better second order diversity when used with a single receive antenna and fourth order diversity when used with two antennas at the receiver side. But, it is only half rate, because it only transmits two symbols using the two time slots and two transmit antenna. 1.2 LITERATURE REVIEW [1]S. M. Alamouti, describes a simple two-branch transmit diversity scheme. Using two transmit antenna and one receive antenna, the new transmit antenna provides the same diversity order as maximal-ratio receiver combining (MRRC) with one transmit and two receive antennas. The scheme easily be generated to two transmit antenna and M receive antenna to provide a diversity order of 2M. This scheme does not require any bandwidth expansion any feedback from the receiver to the

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