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US 7,443,827 B2Granted
Mobile communication system, multicarrier CDMA transmitter, and multicarrier CDMA receiver
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorHiroyasu Sano
Life of this patent
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Abstract
A transmitting apparatus adds a common pilot symbol and known series for each data slot of a subcarrier group. A receiving apparatus combines SIR calculation values obtained for each subcarrier group, and averages the SIR calculation values. Based on this, it is possible to obtain a high-precision SIR calculation value even when there is a level fluctuation such as shadowing.
Claims25
A mobile communication system, which employs multicarrier code division multiple access, comprising a transmitting apparatus and a receiving apparatus,
- the transmitting apparatus having
- a slot generating unit that (1) generates, for each subcarrier group unit, a slot consisting of (a) a common pilot portion that is not used by a receiving apparatus to estimate a signal to interference ratio, (b) a known series portion, different from the common pilot portion, which the receiving apparatus uses to estimate the signal-to-interference ratio for each subcarrier group, and (c) a data portion, by using transmission data converted for each subcarrier group, (2) copies each slot by a predetermined number of subcarriers, and (3) outputs the slots;
- a modulating unit that modulates the signal copied for each subcarrier unit within the subcarrier group;
- a spread spectrum unit that individually carries out frequency spreading to a subcarrier signal within the modulated subcarrier group;
- a transmission power control unit that controls transmission power of the subcarrier signal after the spreading, for each subcarrier group;
- a multiplexing unit that multiplexes the subcarrier signal after the transmission power control, for each subcarrier group;
- and
- a transmitting unit that generates a predetermined signal by carrying out an inverse Fourier transformation processing, a guard interval setting processing, and a frequency conversion processing to the multiplexed subcarrier signal, and transmits the signal generated to a transmission line, and
- the receiving apparatus having
- a receiving unit that receives a signal on a transmission line, converts the signal received into a baseband signal, and carries out a Fourier transformation processing to the baseband signal;
- a common pilot extracting unit that extracts a common pilot portion included in each of the Fourier-transformed subcarrier signals;
- a channel estimating unit that calculates a channel estimate value for each subcarrier, by using the common pilot portion;
- a delay unit that delays each Fourier-transformed subcarrier signal by a time required to carry out the extraction processing and the channel estimate processing;
- a fading compensating unit that carries out a fading compensation to each of the delayed subcarrier signals, by using each of the channel estimate values;
- an inverse spread spectrum unit that inverse spreads a frequency of each of the fading-compensated subcarrier signals;
- an SIR estimating unit that estimates, for each subcarrier group signal, a signal to interference ratio by using the known series portion included in each subcarrier group signal after the inverse spreading, wherein the SIR estimating unit includes a subcarrier group averaging unit that averages the estimated signal-to-interference ratios corresponding to each subcarrier group and a known series extracting unit that extracts the known series portion from each subcarrier group signal;
- and
- a demodulating unit that demodulates the subcarrier group signal after the inverse spreading.
15 more elements
A multicarrier code division multiple access transmitting apparatus, comprising:
- a slot generating unit that (1) generates, for each subcarrier group unit, a slot consisting of (a) a common pilot portion that is not used by a receiving apparatus to estimate a signal to interference ratio, (b) a known series portion, different from the common pilot portion, which the receiving apparatus uses to estimate the signal to interference ratio for each subcarrier group, and (c) a data portion, by using transmission data converted for each subcarrier group, (2) copies each slot by a predetermined number of subcarriers, and (3) outputs the slots;
- a modulating unit that modulates the copied signal for each subcarrier unit within the subcarrier group;
- a spread spectrum unit that frequency spreads a spectrum of each of the subcarrier signals within the modulated subcarrier group;
- a transmission power control unit that controls transmission power of the subcarrier signal after the spreading, for each subcarrier group based on reception signal quality at the receiving apparatus;
- a multiplexing unit that multiplexes the subcarrier signal after the transmission power control, for each subcarrier group;
- and
- a transmitting unit that generates a predetermined signal by carrying out an inverse Fourier transformation processing, a guard interval setting processing, and a frequency conversion processing to the multiplexed subcarrier signal, and transmits the generated signal to a transmission line.
4 more elements
A multicarrier code division multiple access receiving apparatus, comprising:
- a receiving unit that converts a received signal on a transmission line into a baseband signal, and carries out a Fourier transformation processing to the baseband signal;
- a common pilot extracting unit that extracts a common pilot portion included in each of the Fourier-transformed subcarrier signals;
- a channel estimating unit that calculates a channel estimate value for each subcarrier, by using the common pilot portion;
- a delay unit that delays each Fourier-transformed subcarrier signal by a time required to carry out the extraction processing, and the channel estimate processing;
- a fading compensating unit that carries out a fading compensation to each of the delayed subcarrier signals, by using each of the channel estimate values;
- an inverse spread spectrum unit that inverse spreads a frequency of each of the fading-compensated subcarrier signals;
- an SIR estimating unit that estimates, for each subcarrier group signal, a signal-to-interference ratio by using a known series portion, different from the common pilot portion, included in each subcarrier group signal after the inverse spreading, wherein the SIR estimating unit includes a subcarrier group averaging unit that averages the estimated signal-to-interference ratios corresponding to each subcarrier group and a known series extracting unit that extracts the known series portion from each subcarrier group signal;
- and
- a demodulating unit that demodulates the subcarrier group signal after the inverse spreading.
6 more elements
Dependencies are inferred from the claim text.