Source: http://www.google.ca/patents/US20070173206
Timestamp: 2017-11-24 20:33:47
Document Index: 756521152

Matched Legal Cases: ['Application No. 2001', 'Application No. 2002', 'Application No. 11', 'art 118', 'art 104', 'art 104', 'art 118', 'art 106', 'art 208', 'art 104', 'art 208', 'art 212', 'art 212', 'art 212', 'art 212', 'art 214', 'art 214', 'art 214', 'art 214', 'art 216', 'art 222', 'art 208', 'Application No. 6', 'art 222', 'art 208', 'art 222', 'art 226', 'art 228', 'art 224', 'art 226', 'art 214', 'art 214', 'art 228']

Patent US20070173206 - Radio channel control method and receiving apparatus - Google Patents
A radio channel control method for controlling, in a radio communication system having a transmitter and a receiver, a radio channel from the transmitter toward the receiver. The method includes receiving a signal transmitted from the transmitter by the receiver, measuring reception quality of the signal,...http://www.google.ca/patents/US20070173206?utm_source=gb-gplus-sharePatent US20070173206 - Radio channel control method and receiving apparatus
Publication number US20070173206 A1
Application number US 11/730,671
Also published as US7881740, US7885677, US7933624, US7945280, US8073396, US8073480, US8095171, US8135341, US8311569, US8331976, US8483736, US8660599, US20050130692, US20070173204, US20070173205, US20070184784, US20110092166, US20110111702, US20110117857, US20110136440, US20110143681, US20110165852, US20130157583
Publication number 11730671, 730671, US 2007/0173206 A1, US 2007/173206 A1, US 20070173206 A1, US 20070173206A1, US 2007173206 A1, US 2007173206A1, US-A1-20070173206, US-A1-2007173206, US2007/0173206A1, US2007/173206A1, US20070173206 A1, US20070173206A1, US2007173206 A1, US2007173206A1
US 20070173206 A1
receiving a signal transmitted from the transmitter by the receiver;
measuring reception quality of the signal;
generating information which indicates increment or decrement of the reception quality; and
controlling a modulation or coding for the radio channel based on the information.
2. The radio channel control method according to claim 1, wherein the information is generated by comparing the reception quality with a reference quality to be compared.
3. The radio channel control method according to claim 2, wherein the information includes a bit “1” when the information indicates better reception quality than the reference quality and the information includes a bit “0” when the information indicates worse reception quality than the reference quality.
In radio communication, in particular in a mobile communication, a radio channel set between communication apparatuses which carry out information transmission/reception is likely to fluctuate. In order to carry out information transmission using such a radio channel appropriately transmission parameters of the radio channel is appropriately changed. The transmission parameters include, for example, a modulation method, a coding rate, a ratio of the number of true information bits with respect to the number of total transmission bits including redundancy bits such as error correction bits (referred to as a ‘Rate-Matching ratio’, hereinafter), or the number of spreading codes used in a CDMA (Code Division Multiple Access) communication.
(Patent Document 2) Japanese Laid-open Patent Application No. 2001-339458;
(Patent Document 3) Japanese Laid-open Patent Application No. 2002-84578; and
(Patent Document 4) Japanese Laid-open Patent Application No. 11-88940.
Change of the transmission parameters of the downlink radio-channel from the base station 100 toward the mobile station 200 is carried out by the following procedures. That is, based on the coding rate which is the transmission parameter notified of from the transmission parameter setting part 118, the encoder 102 of the base station 100 encodes input data to be transmitted. Further, the encoder 102 outputs the encoded data obtained from the encoding to the modulation part 104. The modulation part 104 demodulates a base band signal with the encoded data based on the modulation method notified of by the transmission parameter setting part 118, and outputs it to the transmission part 106.
The demodulation part 208 applies a demodulation method corresponding to the modulation method applied by the modulation part 104 of the base station 100, and demodulates the input signal.
Further, the demodulation part 208 outputs the thus-obtained encoded data to the decoder 210. The decoder 210 applies a decoding method corresponding to the encoding method applied by the encoder 102 of the base station 100, decodes the input encoded data, and outputs data obtained from the decoding.
The TPC bit generation part 212 compares the input SIR with a predetermined reference value, and, based on the comparison result, generates a bit (referred to as a ‘TPC bit’, hereinafter) for ordering the base station 100 to increase or decrease of transmission power of the downlink radio channel. Specifically, the TPC bit generation part 212 generates the TPC bit ‘0’ for ordering the base station 100 to increase the transmission power in a case where the SIR is less than the reference value since the propagation environment of the downlink radio channel is bad, while, the TPC bit generation part 212 generates the TPC bit ‘1’for ordering the base station 100 to decrease the transmission power in a case where the SIR is equal to or higher than the reference value since the propagation environment of the downlink radio channel is good. Further, the TPC bit generation part 212 outputs the generated TPC bit to the transmission parameter determination part 214.
For example, it is assumed that the modulation method currently applied by the base station 100 is QPSK and the coding rate is 3/4. In this case, the transmission parameter value ‘2’ corresponds to these transmission parameters according to FIG. 3. The transmission parameter determination part 214 increases the transmission parameter value by 1 into ‘3’when the input TPC bit is ‘0’, and determines the transmission parameters (the modulation method is 16QAM, and the coding rate is ½) corresponding to the transmission parameter. value ‘3’as new transmission parameters. On the other hand, the transmission parameter determination part 214 decreases the transmission parameter value by 1 into ‘1’. when the input TPC bit is ‘1’, and determines the transmission parameters (the modulation method is QPSK, and the coding rate is ½) corresponding to the transmission parameter value ‘1’as new transmission parameters. The transmission parameter determination part 214 outputs the tramsmission prater value corresponding to the new transmission parameters to the transmission baseband determination part 216.
In the second embodiment described above, it is possible to reduce a frequency of transmitting the transmission parameter value to the base station 100, in comparison to the, case of the first embodiment. Accordingly, it is possible to widen a band available for transmitting information other than the transmission parameter in the uplink radio channel from the mobile station 200 toward the base station 100.
The moving speed detection part 222 detects a moving speed of the mobile station 200 based on a fluctuation of receiving power of a signal input to the demodulation part 208. As a specific method of detecting the moving speed, for example, see Japanese Laid-open. Patent Application No. 6-514586. The moving speed detection part 222 should not necessarily apply the signal input to the demotion part 208 to detect the moving speed of the mobile station 200. For example, any other method, by which the moving speed of the mobile station 200 may be detected, may be applied. For example, a function of a GPS (Global Positioning System) or such may be applied. The moving speed detection part 222 outputs the thus-detected moving speed of the mobile station 200, to the majority decision circuit 220.
In the reference value setting part 226, a reference value of the SIR is set. The comparison part 228 compares the SIR measured by the SIR measurement part 224 (referred to as a ‘SIR measurement value ’hereinafter) and the SIR reference value set in the reference value setting part 226, and outputs a result thereof to the majority decision circuit 230.
The majority decision circuit 230 may output, in addition to the comparison result which is one occurring more, a difference between the, comparison results which are one occurring more and the comparison results which are one occurring less, to the transmission parameter determination part 214. In this case, assuming that the relationship between the transmission parameter values and the transmission parameters is that shown in FIG. 3, the transmission parameter determination part 214 increases a changing amount of the transmission parameter value corresponding to the transmission parameters currently applied by the base station 100 as the difference is larger, and then determines the transmission parameters corresponding to the thus-changed transmission parameter value as new transmission parameters.
The same as in the fourth embodiment, the majority decision circuit 230 determines, as to the comparison results input from the comparison part 228 during a second predetermined period, which is one occurring more between the comparison result indicating that the SIR measurement value is more than the SIR reference value and the comparison result indicating that the SIR measurement value is less than the SIR reference value. However, when the moving speed of the mobile station 200 is equal to or more than a predetermined value, since there is a high possibility that the propagation environment of the downlink radio channel changes for a large amount during a short period, the majority decision circuit 230 shortens the second predetermined period. Further, when the moving speed of the mobile station 200 is less than the predetermined value, since there is a low possibility that the propagation environment of the downlink-radio channel changes for a large amount during a short period, the majority decision circuit 230 elongates the second predetermined period.
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U.S. Classification 455/70
International Classification H04B7/00, H04B7/005, H04B1/00
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FURUKAWA, HIDETO;DATEKI, TAKASHI;REEL/FRAME:019197/0523