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公开(公告)号：JP2001069190A
公开(公告)日：2001-03-16
申请号：JP2000224835
申请日：2000-07-26
Applicant: LUCENT TECHNOLOGIES INC
Inventor： KRISHNAMOORTHY RAJEEV , LI XIADONG , NARAYANASWAMY SHANKAR , RUPP MARKUS , VISWANATHAN HARISH
Abstract: PROBLEM TO BE SOLVED: To vary a user data carrying speed by composing specific one of systems for mapping to multiple multiplex signal point arrangements used by time slots of a step determined by the preamble of a specific time slot. SOLUTION: A conditional branch point 305 tests whether or not the output corresponding to a training sequence P1 is larger than the output corresponding to a training sequence P2. When the result is YES, that shows that the received training sequence is QPSK-modulated, the control advances to a step 307, packets are modulated by QPSK. Then the system for mapping to a specific signal point arrangement used for user data of a time slot is shown by the preamble of the time slot and a reception side is able to determine a system for mapping to the signal point arrangement used for each time slot.
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公开(公告)号：JP2001069189A
公开(公告)日：2001-03-16
申请号：JP2000224834
申请日：2000-07-26
Applicant: LUCENT TECHNOLOGIES INC
Inventor： KRISHNAMOORTHY RAJEEV , LI XIADONG , NARAYANASWAMY SHANKAR , RUPP MARKUS , VISWANATHAN HARISH
Abstract: PROBLEM TO BE SOLVED: To vary a user data carrying speed by making it possible to use systems for mapping to several signal point arrangements and making each constitution capable of transmitting a different number of bits for each symbol. SOLUTION: A representative frame structure 201 used for a radio communication system for an operable beam has 64 time slots 203 in itself, i.e., has 203-1 to 203-64. Each time slot 203 has a data part(DP) 205 and a protection part (G) 207. Then the system for mapping to signal point arrangement can be changed basically by the time slots 203. Advantageously, the number of time slots used by a user is changed basically by the time slots and then the data carrying speed of the user can speedily be increased or decreased.
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公开(公告)号：JP2002009735A
公开(公告)日：2002-01-11
申请号：JP2001138083
申请日：2001-05-09
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LI XIADONG , PAPADIAS CONSTANTINOS BASIL , VISWANATHAN HARISH
Abstract: PROBLEM TO BE SOLVED: To provide an orthogonal frequency division multiplexing transmission diversity system that can be used for a frequency selective fading channel in wireless communication. SOLUTION: A control system selector 205 supplies a signal Y0 to an even OFDM interval and a signal Y'1 in an odd number OFDM interval as an output supplied to a cyclic prefix unit 209 under the control of a selection input 217. The cyclic prefix unit 209 has a cyclic prefix prepositioned to each OFDM interval, that is each symbol period. A digital/analog converter 210 converts the signals Y0, Y'1 into analog signals, which are fed to an RF transmitter 211 for the transmission through an antenna 212, that is an antenna 0.
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公开(公告)号：AU4028701A
公开(公告)日：2001-11-15
申请号：AU4028701
申请日：2001-05-02
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LI XIADONG , VISWANATHAN HARISH , PAPADIAS CONSTANTINOS B
Abstract: Wireless communications for frequency-selective fading channels is realized by employing a system including orthogonal frequency division multiplexing (OFDM) in combination with an at least two antenna transmit diversity arrangement. Specifically, OFDM converts a multipath channel into a plurality of narrowband subchannels each having flat fading. Then, the signals on the same frequency subchannels of the at least two antennas are grouped together. Considering a first frequency subchannel, during a first OFDM time interval, a first signal and a second signal are transmitted on the first frequency subchannel from a first antenna (0) and from a second antenna (1), respectively. During a second OFDM time interval, a reverse sign (-) complex conjugate of the second signal and a complex conjugate of the first signal are transmitted from the first antenna and the second antenna, respectively. In a specific embodiment of the invention, reduced complexity in the implementation is realized by a reverse order complex conjugate and a reverse order, reverse sign (-) complex conjugate and judicious selection of the processed data signals in order to transmit the appropriate ones of the signals during the first and second OFDM intervals. Again, if the channel remains constant over the two OFDM intervals, diversity combination is realized for each frequency subchannel. In another embodiment of the invention, antenna-group hopping is employed in conjunction with pairing in time of the OFDM frequency subchannel signals to realize increased transmit diversity without rate loss.
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