EP0680160A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for transmission power control of a mobile station during soft handoff in a CDMA system
Assignee: NTT Docomo Inc
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Filing: 1995-04-25
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Granted: —
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Expires: 2015-04-25
Abstract
Abstract A transmission power control method in CDMA, which is capable of increasing the capacity in terms of the number of subscribes by reducing transmission power by achieving highly accurate transmission power control during a soft handoff. A mobile station (PS1) determines its transmission power during the soft handoff by comparing a transmission power control bit from the old base station (BS1) with that from a new base station (BS2), and by selecting the transmission power control bit that indicates lower transmission power of the mobile station (PS1). In addition, the mobile station (PS1) determines the transmission power control bit for the base stations (BS1,BS2) by comparing the received SIR from the old base station (BS1) with that from the new base station (BS2), and by selecting the greater received SIR. This make it possible to reduce the transmission power, and increase the capacity in terms of the number of subscribers.
Inventors
- 👤 Tomohiro Dohi
- 👤 Koji Ohno
- 👤 Mamoru Sawahashi
- 👤 Akihiro Higashi
- 👤 Narumi Umeda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 17:45
CPC Classifications
H; H04; H04W; H04W52/00; H04W52/04; H04W52/38; H04W52/40; H04W36/00; H04W36/08; H04W36/083; H04W52/18; H04W52/24; H04W36/16; H04W36/18; Y; Y02; Y02D; Y02D30/00; Y02D30/70
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
189 words
A transmission power control method during a soft handoff which transfers communications between a mobile station and an old base station to communications between the mobile station and a new base station in a CDMA (Code Division Multiple Access) system, said transmission power control method characterized by comprising the steps of: extracting, at said mobile station, a first transmission power control bit which designates transmission power of the mobile station, from a received signal transmitted from said old base station; extracting, at said mobile station, a second transmission power control bit which designates transmission power of the mobile station, from a received signal transmitted from said new base station; comparing, at said mobile station, the transmission power designated by said first transmission power control bit and the transmission power designated by said second transmission power control bit; selecting, at said mobile station, one of said first transmission power control bit and said second transmission power control bit, a selected transmission power control bit designating lower transmission power; and controlling, at said mobile station, the transmission power of said mobile station in accordance with said selected transmission power control bit.
Claim 2
Dependent Claim
70 words
The transmission power control method as claimed in claim 1, characterized in that said mobile station performs said soft handoff with said old base station and said new base station by using one of the combinations of an identical spreading code and an identical transmission frequency, different spreading codes and an identical transmission frequency, an identical spreading code and different transmission frequencies, and different spreading codes and different transmission frequencies.
Claim 3
Dependent Claim
177 words
A transmission power control method during a soft handoff which transfers communications between a mobile station and an old base station to communications between the mobile station and a new base station in a CDMA (Code Division Multiple Access) system, said transmission power control method characterized by comprising the steps of: measuring, at said mobile station, a first SIR (Signal-to-Interference Ratio) of a received signal from said old base station to interference; measuring, at said mobile station, a second SIR of a received signal from said new base station to the interference; comparing, at said mobile station, the first SIR with the second SIR; selecting, at said mobile station, one of said first SIR and said second SIR, a selected SIR being greater than the other; deciding, at said mobile station, in accordance with the selected SIR, a transmission power control bit for determining transmission power of said old base station and said new base station; and transmitting said transmission power control bit from said mobile station to said old base station and said new base station.
Claim 4
Dependent Claim
70 words
The transmission power control method as claimed in claim 3, characterized in that said mobile station performs said soft handoff with said old base station and said new base station by using one of the combinations of an identical spreading code and an identical transmission frequency, different spreading codes and an identical transmission frequency, an identical spreading code and different transmission frequencies, and different spreading codes and different transmission frequencies.
Claim 5
Dependent Claim
158 words
The transmission power control method as claimed in claim 1, characterized by further comprising the steps of: measuring, at said mobile station, a first SIR (Signal-to-Interference Ratio) of the received signal from said old base station to interference; measuring, at said mobile station, a second SIR of the received signal from said new base station to the interference; comparing, at said mobile station, the first SIR with the second SIR; selecting, at said mobile station, one of said first SIR and said second SIR, a selected SIR being greater than the other; deciding, at said mobile station, in accordance with the selected SIR, a third transmission power control bit for determining transmission power of said old base station and said new base station; and transmitting said third transmission power control bit from said mobile station to said old base station and said new base station at transmission power controlled in accordance with said selected transmission power control bit.
Claim 6
Dependent Claim
70 words
The transmission power control method as claimed in claim 5, characterized in that said mobile station performs said soft handoff with said old base station and said new base station by using one of the combinations of an identical spreading code and an identical transmission frequency, different spreading codes and an identical transmission frequency, an identical spreading code and different transmission frequencies, and different spreading codes and different transmission frequencies.
Claim 7
Dependent Claim
176 words
A mobile station performing transmission power control during a soft handoff which transfers communications between a mobile station and an old base station to communications between the mobile station and a new base station in a CDMA (Code Division Multiple Access) system, said mobile station characterized by comprising: means for extracting a first transmission power control bit which designates transmission power of the mobile station, from a received signal transmitted from said old base station; means for extracting a second transmission power control bit which designates transmission power of the mobile station, from a received signal transmitted from said new base station; means for comparing the transmission power designated by said first transmission power control bit and the transmission power designated by said second transmission power control bit; means for selecting one of said first transmission power control bit and said second transmission power control bit, a selected transmission power control bit designating lower transmission power; and means for controlling the transmission power of said mobile station in accordance with said selected transmission power control bit.
Claim 8
Dependent Claim
68 words
The mobile station as claimed in claim 7, characterized in that said mobile station performs said soft handoff with said old base station and said new base station by using one of the combinations of an identical spreading code and an identical transmission frequency, different spreading codes and an identical transmission frequency, an identical spreading code and different transmission frequencies, and different spreading codes and different transmission frequencies.
Claim 9
Dependent Claim
164 words
A mobile station performing transmission power control during a soft handoff which transfers communications between a mobile station and an old base station to communications between the mobile station and a new base station in a CDMA (Code Division Multiple Access) system, said mobile station characterized by comprising: means for measuring a first SIR (Signal-to-Interference Ratio) of a received signal from said old base station to interference; means for measuring a second SIR of a received signal from said new base station to the interference; means for comparing the first SIR with the second SIR; means for selecting one of said first SIR and said second SIR, a selected SIR being greater than the other; means for deciding, in accordance with the selected SIR, a transmission power control bit for determining transmission power of said old base station and said new base station; and transmitting said transmission power control bit from said mobile station to said old base station and said new base station.
Claim 10
Dependent Claim
68 words
The mobile station as claimed in claim 9, characterized in that said mobile station performs said soft handoff with said old base station and said new base station by using one of the combinations of an identical spreading code and an identical transmission frequency, different spreading codes and an identical transmission frequency, an identical spreading code and different transmission frequencies, and different spreading codes and different transmission frequencies.
Claim 11
Dependent Claim
145 words
The mobile station as claimed in claim 7, further characterized by comprising: means for measuring a first SIR (Signal-to-Interference Ratio) of the received signal from said old base station to interference; means for measuring a second SIR of the received signal from said new base station to the interference; means for comparing the first SIR with the second SIR; means for selecting one of said first SIR and said second SIR, a selected SIR being greater than the other; means for deciding, in accordance with the selected SIR, a third transmission power control bit for determining transmission power of said old base station and said new base station; and means for transmitting said third transmission power control bit from said mobile station to said old base station and said new base station at transmission power controlled in accordance with said selected transmission power control bit.
Claim 12
Dependent Claim
68 words
The mobile station as claimed in claim 11, characterized in that said mobile station performs said soft handoff with said old base station and said new base station by using one of the combinations of an identical spreading code and an identical transmission frequency, different spreading codes and an identical transmission frequency, an identical spreading code and different transmission frequencies, and different spreading codes and different transmission frequencies.
Claim 13
Dependent Claim
42 words
A transmission power control method for implementation by one mobile station communicating with multiple base stations, wherein during a hand-over period, in which the mobile station communicates with two base stations, the mobile station implements a closed loop transmission power level control.
Claim 14
Dependent Claim
54 words
A transmission power control method according to claim 13 wherein said closed loop control is implemented by reference to indicated power levels and/or signal to noise ratios of signals received from the two base stations, selecting the lower of the indicated transmission power levels and/or the greater of the received signal to noise ratios.
Claim 15
Dependent Claim
28 words
A method according to claim 13 or 14 wherein each signal received from a base station contains a transmission power control bit for extraction at the mobile station.
Claim 16
Independent Claim
14 words
A method or apparatus having the features of any combination of the preceding claims.
References Cited (Backward Citations)
No citation records indexed.
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