EP0471656A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A method and apparatus for enhancing signalling reliability in a cellular mobile radio telephone system
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1991-08-16
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Granted: —
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Expires: 2011-08-16
Abstract
Abstract A method and apparatus for achieving reliable transmission of signalling messages in a cellular system in which the frequency plan, frequency/time slot allocation plan, code channel allocation plan, or dynamic/adaptive channel allocation rule of the system is violated by allowing adjacent base stations to reuse particular frequencies/time slots/channels for signalling a particular mobile station. In situations where signalling messages, such as handoff commands, which are communicated between a base station and a mobile station are not properly received by the mobile station, an alternate communications channel will be established to ensure the reception of these messages. The alternate channel is provided by repeating the message through a channel associated with a base station which has better radio characteristics. The channel selected for transmission of the message by the new base station will be on the same frequency/time slot/code as used by the established connection.
Inventors
- 👤 Walter Ghisler
- 👤 Jan Erik Ake Steinar Dahlin
- 👤 Harald Kallin
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 20:59
CPC Classifications
H; H04; H04W; H04W12/00; H04W12/04; H04W36/00; H04W36/0005; H04W36/0055; H04W36/0064; H04W36/08; H04W36/083; H04W36/24; H04W36/30
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
72 words
A method for achieving a handoff of a call connection between a mobile station and a first base station to a second base station in a cellular radio telephone system, comprising the steps of: transmitting a handoff command from said second base station to said mobile station on a first predetermined channel, and determining whether said mobile station transmits radio signals in accordance with said handoff command from said second base station.
Claim 2
Dependent Claim
42 words
A method according to claim 1, wherein said first channel is normally assigned to said first base station at the time of said handoff command for the transmission of signals to mobile stations and not normally assigned to said second base station.
Claim 3
Dependent Claim
42 words
A method according to claim 2, further comprising the step of inhibiting transmission of signals from said first base station on said first predetermined channel while said handoff command is being transmitted from said second base station on said first predetermined channel.
Claim 4
Dependent Claim
42 words
A method according to claim 2, further comprising the step of handing off said call connection from said first base station to said second base station in response to an acknowledgement from said mobile station that said handoff command has been received.
Claim 5
Dependent Claim
103 words
A method according to claim 2, further comprising the step of transmitting a revert command from said first base station to said mobile station on a second channel which is different from said first channel and is normally assigned to said second base station at the time of said handoff command, said revert command instructing said mobile station to reestablish said call connection between said mobile station and said first base station, in response to said mobile station receiving said handoff command on said first channel and being unsuccessful in establishing said call connection between said mobile station and said second base station.
Claim 6
Dependent Claim
30 words
A method according to claim 3, wherein said step of inhibiting includes blocking signals from said first base station on said first channel from being transmitted by a radio transmitter.
Claim 7
Dependent Claim
42 words
A method according to claim 3, wherein said step of inhibiting transmission of signals from said first base station on said first channel involves switching a radio transmitter associated with said first base station to a channel different than said first channel.
Claim 8
Independent Claim
154 words
A method for achieving a handoff of a call connection between a mobile station and a first base station associated with a first cellular radio coverage area to a second base station associated with a second cellular radio coverage area in a cellular mobile radio communication system, comprising the steps of: determining whether said call connection between said mobile station and said first base station will require a handoff to said second base station; transmitting a first handoff command from said first base station to said mobile station on a first channel normally assigned to said first base station at the time of said first handoff command; and transmitting a second handoff command from said second base station to said mobile station on said first channel normally assigned to said first base station in response to said mobile station not receiving said first handoff command on said first channel from said first base station.
Claim 9
Dependent Claim
45 words
A method according to claim 8, further comprising the step of handing off said call connection between said mobile station and said first base station to said second base station in response to said mobile station receiving said second handoff command on said first channel.
Claim 10
Dependent Claim
94 words
A method according to claim 8, wherein said mobile station receives said first handoff command on said first channel and is unsuccessful in establishing said call connection between said mobile station and said second base station, further comprising the steps of: deactivating transmissions from said second base station on a second channel normally associated with said second base station; transmitting a revert command from said first base station to said mobile station on said second channel instructing said mobile station to reestablish said call connection between said mobile station and said first base station.
Claim 11
Dependent Claim
77 words
A method according to claim 8, further comprising the step of switching off a radio transmitter associated with said second base station, which provides said second channel, in order to avoid the use of said second channel by said second base station from disturbing the use of said second channel by said first base station, in response to said mobile station being unsuccessful in establishing said call connection between said mobile station and said second base station.
Claim 12
Independent Claim
153 words
A method for enhancing the reliability of message transmissions in a cellular radio telephone system which includes at least a mobile station, a first base station, and a second base station, comprising the steps of: transmitting messages from said first base station to said mobile station via a communication connection on a first channel associated with said first base station; determining whether the signal strength or quality of said communication connection on said first channel between said mobile station and said first base station is suitable for maintaining said communication connection on said first channel; utilizing a second channel associated with said second base station in response to a determination that the signal strength or quality of said communication connection on said first channel is not suitable for maintaining said communication connection; and transmitting said messages from said second base station to said mobile station via said communication connection on said second channel.
Claim 13
Dependent Claim
24 words
A method according to claim 12 in a FDMA system comprising the further step of providing said first and second channels on identical frequencies.
Claim 14
Dependent Claim
29 words
A method according to claim 12 in a TDMA system comprising the further step of providing said first and second channels on identical time slots of the same frequency.
Claim 15
Dependent Claim
151 words
A cellular radio telephone system having at least one mobile station, a first base station associated with a first cellular radio coverage area, a second base station associated with a second cellular radio coverage area, and a mobile switching center, said system comprising: determining means for determining whether an active call connection between said mobile station and said first base station will require a handoff to said second base station; first transmitting means for transmitting a handoff command from said first base station to said mobile station on a first channel associated with said first base station in response to said determining means determining that a handoff is required; and second transmitting means for transmitting a handoff command from a second base station to said mobile station on said first channel in response to said mobile station not receiving said handoff command from said first base station on said first channel.
Claim 16
Dependent Claim
50 words
A system according to claim 15, further comprising handoff means for handing off said call connection between said mobile station and said first base station to said second base station in response to said mobile station receiving said handoff command transmitted from said second base station on said first channel.
Claim 17
Dependent Claim
68 words
A system according to claim 15, further comprising switching means for switching off a radio transmitter associated with said second base station, which provides said second channel, in order to avoid the use of said second channel by said second base station from disturbing the use of said second channel by said first base station while the first base station sends a revert order to said mobile station.
Claim 18
Dependent Claim
189 words
A cellular radio telephone system which includes at least a mobile station, a first base station, a second base station and a mobile switching center, said system comprising: transmitting means for transmitting messages from said first base station to said mobile station over a communication connection on a first channel associated with said first base station; determining means for determining whether the signal strength or quality of said communication connection on said first channel between said mobile station and said first base station is suitable for maintaining said communication connection on said first channel; utilizing means for utilizing a second channel associated with the said second base station in response to a determination that the signal strength or quality of said communication connection on said first channel between said mobile station and said first base station is not suitable for maintaining said communication connection; and transmitting means for transmitting said messages from said second base station to said mobile station over said communication connection on said second channel, said first channel and said second channel being provided by said first and second base stations, respectively, on the same frequency.
References Cited (Backward Citations)
No citation records indexed.
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