Device and method for realizing beam forming in CDMA system

Abstract

The present invention relates to a method and apparatus. For implementing beam forming in CDMA communication system . It provides a plurality of fixed beams formed within a sector. A plurality of fixed beams used in the same smart antennas system are formed narrow beam traffic channel and common channel having sector beam at the same time, It can overcome the differ from the change of time and temperature with phase of each path, So it need not complex technique of calibration, The capacity and performance in multi-antennas CDMA system have been improved. It resolves the problem that the coherent of each of fixed beams of space vector overlaps at some areas, when it transmits the common channel in multi-antennas CDMA system. The intensity of the polite channels and traffic channels becomes corresponding proportion; the received signal's ratio of the signal to noise is increased in mobile stations. The optical transceiver system is set between baseband and TRX; the more carriers are sustained in the baseband system. The distance between the device of radio frequency and the antenna is very close; the power cost is reduce.

Description

Technical field [0001] The invention belongs to the field of mobile communication, and relates to a device and method for implementing beamforming in a code division multiple access system. More precisely, it relates to a device and method for implementing beamforming using smart antenna technology in a code division multiple access (CDMA) mobile communication system. Background technique [0002] In recent years, CDMA mobile communication systems have achieved great development and applications. The most typical examples are CDMA95 and CDMA2000 mobile communication systems that are currently commercially available. Compared with other mobile communication systems (such as time division multiple access TDMA, frequency division multiple access FDMA system), the CDMA system has advantages in capacity and service quality, but the users of the CDMA system share a wideband channel. The characteristics of co-channel interference (CCI) between users limit the capacity of the CDMA system...

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Problems solved by technology

The offset frequency range recommended by the patent is 30-120Hz, that is, if the commonly used three beams per sector are used, the carrier offset of this part will reach ±30-120Hz, which is the lowest for base stations of IS-97 (CDMA95 and CDMA2000) Performance test standard) stipulates that the TX frequency tolerance of the base station is <±0.05ppm. It can be seen that if the base station frequency is in the 800MHz frequency band, only this part of the frequency offset is already close to or exceeds the frequency tolerance of the base station transmission. For mobile stations, it will cause the degradation of demodulation performance

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