摘要:
A base station includes a center frequency setting unit, a local oscillator, a baseband processor, and an RF processor. In the event of a frequency band change, the center frequency setting unit sets a center frequency of a use frequency channel to have a predetermined offset value with respect to a center frequency before the frequency band change. The local oscillator generates an LO frequency signal according to the center frequency set by the center frequency setting unit. The baseband processor generates a downlink baseband signal. The RF processor uses the LO frequency signal to convert the downlink baseband signal into an RF signal prior to transmission.
摘要:
A base station includes a center frequency setting unit, a local oscillator, a baseband processor, and an RF processor. In the event of a frequency band change, the center frequency setting unit sets a center frequency of a use frequency channel to have a predetermined offset value with respect to a center frequency before the frequency band change. The local oscillator generates an LO frequency signal according to the center frequency set by the center frequency setting unit. The baseband processor generates a downlink baseband signal. The RF processor uses the LO frequency signal to convert the downlink baseband signal into an RF signal prior to transmission.
摘要:
Disclosed is a hard handover method and system for use in a Broadband Wireless Access (BWA) communication system. The method and system includes dividing a data transmission field for mobile stations (MSs) into a handover field and a normal user field, allocating at least one subchannel in the normal user field to non-handover MSs located in a non-handover region, allocating at least one subchannel in the handover field to handover MSs located in a handover region, and performing communication through the allocated at least one subchannel.
摘要:
Disclosed is a hard handover method and system for use in a Broadband Wireless Access (BWA) communication system. The method and system includes dividing a data transmission field for mobile stations (MSs) into a handover field and a normal user field, allocating at least one subchannel in the normal user field to non-handover MSs located in a non-handover region, allocating at least one subchannel in the handover field to handover MSs located in a handover region, and performing communication through the allocated at least one subchannel.
摘要:
A method for assigning orthogonal codes used for a first system and a second system in a CDMA system including channels of the first system for spreading a pilot signal, a sync signal, a paging signal and a traffic signal with a first set of orthogonal codes corresponding to orthogonal code numbers in different rows from a set of orthogonal codes arranged in a matrix of m rows and m columns, and channels of the second system for spreading a second set of orthogonal codes corresponding to orthogonal code numbers different from said orthogonal code numbers for the first set of orthogonal codes. The orthogonal codes for the second system are transmitted at a data rate higher than a data rate of the first system. The method comprises the steps of: assigning orthogonal codes corresponding to the orthogonal code numbers of the orthogonal code set associated with at least one of 2n rows to the channels of the first system, wherein a set of the orthogonal codes are arranged in a matrix of subsets of orthogonal codes and inversed orthogonal codes, each subset including 2n rows and 2n columns; and assigning orthogonal codes corresponding to the orthogonal code numbers of the orthogonal code set associated with at least one of the remaining rows to the second system.
摘要:
A channel spreading device for a base station in a CDMA communication system is described. The device comprises a spreading code generator for generating a real-component spreading code and an imaginary-component spreading code corresponding to a designated channel spreading code index; a circuit receiving a mode control signal, for disabling generation of the imaginary-component spreading code when the received mode control signal indicates a BPSK (Binary Phase Shift Keying) modulation mode; and a complex multiplier receiving a channel signal, for complex multiplying the received channel signal by the spreading codes to spread the channel signal.
摘要:
A method for generating a complex quasi-orthogonal code for channel spreading in a CDMA communication system is disclosed. The method comprises generating an M-sequence having a length N and a specific sequence having a good full correlation property with the M-sequence; generating a predetermined number of other specific sequences by circularly shifting said specific sequence; generating a predetermined number of other M-sequences by circularly shifting said M-sequence, and column permutating the circularly shifted specific sequences in a same method as a column permutation method for converting the generated M-sequences to Walsh orthogonal codes to generate candidate masks; generating quasi-orthogonal code representatives by operating the candidate masks and the Walsh orthogonal codes having the same length as the mask candidates; and selecting quasi-orthogonal code candidates satisfying a partial correlation between the Walsh orthogonal codes out of the generated quasi-orthogonal code representatives and a partial correlation between different quasi-orthogonal codes, and selecting masks pertinent to generating the selected quasi-orthogonal codes.
摘要:
A demodulation method in a mobile station having a plurality of channels, for receiving a signal from a base station. In one aspect, the base station has a plurality of channels, a BPSK spreader for orthogonally spreading symbol data of each channel with an assigned orthogonal code, and a QPSK spreader for PN-spreading the orthogonally spread signal with a PN code. In the demodulation method, a first QPSK despreader in the mobile station receives PN-spread signal and PN-despreads the PN-spread signal with the PN code, and a second QPSK despreader orthogonally despreads the PN-despread signal with a complex orthogonal code having the real and imaginary parts of the assigned orthogonal code. In another aspect, the base station has a plurality of channels, a QPSK spreader for spreading symbol data of each channel by the real and imaginary parts of its assigned orthogonal code, and a QPSK spreader for PN-spreading the orthogonally spread signal with a PN code. In the demodulation method, a mobile station receives the PN-spread signal from the base station, PN-despreads the received signal with a PN code by a QPSK despreader, and orthogonally despreads the PN-despread signal with the assigned orthogonal code by a BPSK despreader. In both aspects, during the orthogonal despreading, the complex conjugate of the estimated pilot channel value is multiplied by the orthogonally despread signal, for compensation.
摘要:
An apparatus and method are provided for managing sectors in a transmission operation of a base station including a smart antenna system forming directional beams using a plurality of antenna elements. The apparatus and method comprise determining whether a call connected to a mobile station is a voice call or a data call; multiplying a transmission signal to the mobile station by predetermined complex weight vectors selected according to the call type; and forming a transmission beam for a corresponding sector by summing the multiplied values according to the antenna elements.
摘要:
A system includes a first base station (BS) adapted to generate, upon detecting an access request signal for a second BS and transmitted from a mobile terminal (MT), an access detection message indicating the detection, and a network element coupled between the first and second BS and adapted to receive the access detection message. The second BS is adapted to receive the access detection message from the network element.