Abstract:
PURPOSE: An orthogonal frequency division multiple access communication system and a method adopting a spatial division multiple access are provided to increase access success rate by increasing a spatial space having orthogonality through a switched beamforming. CONSTITUTION: A plurality of mobile stations(650) transmits an access signal through a certain access sub-carrier or preset access sub-carrier out of preset access channels(611). A base station(600) receives access signals from the mobile stations through a plurality of antennas and detects signals from the mobile stations accessing to the base station(613). The base station performs a beamforming on the received signals to discriminate them based on a transmitted spatial space(615). The base station assigns data sub-carriers to the mobile stations based on spatial spaces of the mobile stations(617). The assigned data sub-carrier is transmitted to a corresponding mobile station(619). The mobile station transmits data using the assigned data sub-carrier(621).
Abstract:
PURPOSE: A handover method in a base station of a wideband wireless access communication system and a method thereof are provided to request an SS(Subscriber Station) to perform a handover process by a base station, and to perform the handover process in the new base station, thereby distributing a call processing function of the SS. CONSTITUTION: A user terminal reads a DL(Downlink)__MAP message and a UL(Uplink)_MAP message received from a serving base station(1000,1002), and reads a peripheral base station list included in the DL_MAP message(1004). The user terminal measures a CINR for a pilot channel(1006), and decides whether a number of a peripheral base station for measuring the CINR is smaller than a BS_MAX number(1008). If so, the user terminal compares the CINR with a CINR of the serving base station(1010), and transmits a handover request message to the serving base station(1012). The user terminal receives a handover response message(1014), and reads a carrier frequency and an identifier of a target base station(1016). The user terminal changes a frequency into a frequency of the target base station(1018), reads a DL_MAP message and a UL_MAP message from the target base station(1020,1022), and transceives data with the target base station(1024).
Abstract:
An apparatus and method for phase modulating SYNC codes transmitted over downlink pilot time slots DwPTSs when a primary common control physical channel P-CCPCH is transmitted using transmit diversity in an NB-TDD CDMA mobile communication system. The apparatus and method transmits and receives the P-CCPCH signal using the transmit diversity by providing a diversity indicator for changing phase variation of the SYNC codes included in the DwPTSs.
Abstract:
PURPOSE: An apparatus and method for determining the usage of the transmit diversity of a P-CCPCH(Primary Common Control Physical CHannel) in an NB-TDD(Narrow Band Time Division Duplexing) CDMA communication system is provided to obtain a transmit gain by transmitting a P-CCPCH using a transmit diversity in an NB-TDD CDMA communication system. CONSTITUTION: In case that a transmit diversity is used, two orthogonal signals are outputted from an STTD encoder(401). These signals are spread into an identical kind of OVSF codes at multipliers(421,422) respectively, and scrambled into an identical kind of scrambling codes at multipliers(423,424) respectively. The output signal of the multiplier(423) is multiplexed with "Midamble 1" at a MUX(404), and the output signal of the multiplier(424) is multiplexed with "Midamble 2" at a MUX(405). The multiplexed signal of the MUX(404) is multiplexed with signals of different channels, such as an S-CCPCH(411), a DPCH(413), etc., at a time MUX(406). Then the output of the time MUX(406) is transmitted through the first antenna(408). Also the output of the MUX(405) is multiplexed with signals of different channels, such as a DPCH(414), an S-CCPCH(412), etc., at a time MUX(407). Then the output of the time MUX(407) is transmitted through the second antenna(409).