Technique for time-division duplex cordless telecommunication
First Claim
1. A telecommunication system for establishing synchronous time-division two-way communication between first and second devices over a radio channel by exchanging radio signals in alternating bursts carrying digital data such that, during the time-division two-way communication, transmission of one of said alternating bursts from one of the first and second devices is completed before transmission of the next of said alternating bursts by the other of the first and second devices is begun, each of said first and second devices comprising:
- burst format means for (a) arranging digital data into bursts for transmission and (b) obtaining digital data from received bursts in accordance with a format of digital data selected from a plurality of predetermined formats including first and second formats, wherein a burst in said first format includes information for a first logical communication channel (D) which carries signalling data such as device identification codes and instructions between said first and second devices, and also includes information for a second logical communication channel (B) which carries data, such as digitally encoded speech, which is to be communicated between the first and second devices, information for said first logical communication channel being present both before and after information for the second logical communication channel, and wherein a burst in said second format includes information for said first logical communication channel and also includes a synchronization pattern not included in the first format, the synchronization pattern enabling the one of said first and second devices which receives it to determine the timing of the bursts received by it from the other of said first and second devices; and
control means for setting said selected format.
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Accused Products
Abstract
A communication procedure suitable for a cordless telephone system involves time division duplex radio communication between a handset 11 and a base station using alternating bursts of transmission over a single radio channel. Once a radio link has been set up, initial transmissions carry a synchronization logical channel S and a signalling logical channel D multiplexed together, but the link may switch to bursts carrying a communications logical channel B for the speech data and the signalling logical channel D. Burst synchronization is achieved by the asynchronous detection of words in a synchronization channel S. These words have bit patterns reducing the probability of incorrect asynchronous detection of them. If one part ceases to receive handset signals from the other, it transmits a special signal, informing the other part. This enables both parts to detect the failure of a link at substantially the same time, so that their actions to re-establish the link are synchronized.
92 Citations
31 Claims
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1. A telecommunication system for establishing synchronous time-division two-way communication between first and second devices over a radio channel by exchanging radio signals in alternating bursts carrying digital data such that, during the time-division two-way communication, transmission of one of said alternating bursts from one of the first and second devices is completed before transmission of the next of said alternating bursts by the other of the first and second devices is begun, each of said first and second devices comprising:
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burst format means for (a) arranging digital data into bursts for transmission and (b) obtaining digital data from received bursts in accordance with a format of digital data selected from a plurality of predetermined formats including first and second formats, wherein a burst in said first format includes information for a first logical communication channel (D) which carries signalling data such as device identification codes and instructions between said first and second devices, and also includes information for a second logical communication channel (B) which carries data, such as digitally encoded speech, which is to be communicated between the first and second devices, information for said first logical communication channel being present both before and after information for the second logical communication channel, and wherein a burst in said second format includes information for said first logical communication channel and also includes a synchronization pattern not included in the first format, the synchronization pattern enabling the one of said first and second devices which receives it to determine the timing of the bursts received by it from the other of said first and second devices; and control means for setting said selected format. - View Dependent Claims (3, 4, 15, 26, 27, 28)
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2. A method of telecommunication for establishing synchronous time-division two-way communication between first and second devices over a radio channel by exchanging radio signals in alternating bursts carrying digital data such that, during the time-division two-way communication, transmission of one of said alternating bursts from one of the first and second devices is completed before transmission of the next of said alternating bursts by the other of the first and second devices is begun, said method comprising the steps of:
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(a) providing a plurality of predetermined formats for digital data which compose a burst, including first and second formats, wherein a burst in said first format includes information for a first logical communication channel (D) which carries signalling data such as device identification codes and instructions between said first and second devices, and also includes information for a second logical communication channel (B) which carries data, such as digitally encoded speech, which is to be communicated between the first and second devices, information for said first logical communication channel being present both before and after information for the second logical communication channel, and wherein a burst in said second format includes information for said first logical communication channel, and also includes a synchronization pattern not included in the first format, the synchronization pattern enabling the one of said first and second devices which receives it to determine the timing of the bursts received by it from the other of said first and second devices; (b) selecting a burst format from said plurality of predetermined formats; and (c) exchanging said radio signals in alternating bursts carrying digital data in said selected format. - View Dependent Claims (12, 13, 14, 29, 30, 31)
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5. A telecommunication system for establishing synchronous time-division two-way communication between first and second devices over a radio channel by exchanging radio signals in alternating bursts carrying digital data such that, during the time-division two-way communication, transmission of one of said alternating bursts from one of the first and second devices is completed before transmission of the next of said alternating bursts by the other of the first and second devices is begun, said second device comprising:
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burst transmission means for transmitting bursts of digital data; and control means for controlling the burst transmission means to operate in a first mode in which the burst transmission means transmits a burst of said alternating bursts and then ceases transmission to allow a burst of said alternating bursts to be received from the first device, and a second mode in which the burst transmission means transmits asynchronously a burst other than said alternating bursts, said asynchronously transmitted burst comprising one or more first portions of digital data for a logical communication (D), which carries signalling data such as device identification codes, followed by one or more further portions of digital data, and then ceases transmission for a period to allow a reply from the first device to be received, each respective said first portion and said further portion of digital data comprising a respective digital data sequence, the respective digital data sequences being repeated within said first portion or said further portion, respectively, and the digital data sequence for each said further portion of digital data providing a preamble of alternating `1`s and `0`s in a repeating pattern followed by a synchronization pattern to enable the first device to determine timing information about the burst when it receives it. - View Dependent Claims (7)
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6. A method of telecommunication for establishing time-division two-way communication between first and second devices over a radio channel by exchanging radio signals in alternating bursts carrying digital data such that, during the time-division two-way communication, transmission of one of said alternating bursts from one of the first and second devices is completed before transmission of the next of said alternating bursts by the other of the first and second devices is begun, said method comprising the steps of:
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(a) asynchronously transmitting a particular burst other than said alternating bursts with the second device, at a time when the first and second devices are not performing the time-division two-way communication, said particular burst comprising one or more first portions of digital data for a logical communication channel (D), which carries signalling data such as device identification codes, followed by one or more further portions of digital data, each respective said first portion and said further portion of digital data comprising a respective digital data sequence, the respective digital data sequences being repeated within said first portion or said further portion, respectively, and the digital data sequence for each said further portion of digital data providing a preamble of alternating `1`s and 1 0`s in a repeating pattern followed by a synchronization pattern to enable the first device to determine timing information about the burst when it receives it; and
subsequently(b) ceasing said transmission by the second device for a period to enable it to receive a reply from the first device. - View Dependent Claims (16)
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8. A telecommunication system for establishing time-division two-way communication between first and second devices over a radio channel by exchanging radio signals in alternating bursts carrying digital data such that, during the time-division two-way communication, transmission of one of said alternating bursts from one of the first and second devices is completed before transmission of the next of said alternating bursts by the other of the first and second devices is begun, each of said first and second devices comprising:
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burst format means for (a) arranging digital data into bursts for transmission and (b) obtaining digital data from received bursts in accordance with a format of digital data selected from a plurality of predetermined formats including a two-channel format which specifies that a burst includes information both for a first logical communication channel (D), which carries signalling data such as device identification codes and instructions from one of said first and second devices to the other, and for a second logical communication channel (B), which carries data to be communicated between the first and second devices, such as digitally encoded speech, said two channel format being chosen from a predefined group of alternative formats of said two-channel format, said predefined group comprising first and second formats which differ from each other in the amount of information for the first logical communication channel carried in each burst; and control means for choosing which of said predefined group of alternative formats of said two-channel format shall be included in said plurality of predetermined formats, said control means choosing said two-channel format from said predefined group of alternative formats of said two-channel format following transmission of data to the other of said first and second devices relating to the choosing of said two-channel format and reception of data from the other of said first and second devices relating to the choosing of said two-channel format, the control means determining said data to be transmitted taking into account the performance capabilities of the one of the first and second devices in which it is comprised and choosing said two-channel format taking into account said data received from the other of said first and second devices. - View Dependent Claims (10, 11, 20)
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9. A method of telecommunication for establishing time-division two-way communication between first and second devices over a radio channel by exchanging radio signals in alternating bursts carrying digital data such that, during the time-division two-way communication, transmission of one of said alternating bursts from one of the first and second devices is completed before transmission of the next of said alternating bursts by the other of the first and second devices is begun, said method comprising the steps of:
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(a) providing a predetermined plurality of formats; and (b) identifying, in accordance with performance capabilities of said first and second devices, one of a predefined group of formats each of which specifies that a burst includes information both for a first logical communication channel (D), which carries signalling data such as device identification codes and instructions between said first and second devices, and for a second logical communication channel (B), which carries data to be communicated between the first and second devices such as digitally encoded speech, said predefined group of formats comprising first and second formats which differ in the amount of information for the first logical communication channel carried in each burst; and (c) selecting said one identified format for the time-division two-way communication transmission. - View Dependent Claims (17, 18, 19)
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21. A telecommunication device for establishing synchronous time-division two-way communication with another device over a radio channel by exchanging radio signals with said other device in alternating bursts carrying digital data such that, during the time-division two-way communication, reception of one of said alternating bursts from said other devices is completed before transmission of the next of said alternating bursts by said telecommunication device is begun,
said telecommunication device comprising: -
burst format means for (a) arranging digital data into bursts for transmission and (b) obtaining digital data from received bursts in accordance with a format of digital data selected from a plurality of predetermined formats including a first format and a second format, wherein a burst in said first format includes information for a first logical channel (D) which carries signalling data such as device identification codes and instructions between the telecommunication device and said other device, and also includes information for a second logical communication channel (B) which carries data such as digitally encoded speech, which is to be communicated between the telecommunication device and said other device, information for said first logical communication channel being present both before and after information for the second logical communication channel, and wherein a burst in said second format includes information for said first logical communication channel and also includes a synchronization pattern not included in the first format, the synchronization pattern in a burst transmitted by said telecommunication device in said second format enabling said other device to determine the timing of the bursts received by it from the telecommunication device, and the synchronization pattern in a burst received by the telecommunication device in said second format is used by it to determine the timing of bursts received by it from said other device; and control means for setting said selected format.
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22. A telecommunication device for establishing synchronous time-division two way communication with another device over a radio channel by exchanging radio signals in alternating bursts carrying digital data such that, during the time-division two-way communication, reception of one of said alternating bursts from said other devices is completed before transmission of the next of said alternating bursts by said telecommunication device is begun,
said telecommunication device comprising: burst communication means having alternating transmit and receive periods and operable in a first mode to transmit a burst of said alternating bursts in one of said transmits periods and then cease transmission to allow a burst of said alternating bursts to be received from said other device in one of said receive periods so as to participate in said time-division two-way communication, and operable in a second mode for detecting bursts other than said alternating bursts, which other bursts are transmitted by said other device asynchronously with respect to said alternating transmit and receive periods and comprising one or more first portions of digital data for a logical communication channel (D), which carries signalling data such as device identification codes, followed by one or more further portions of digital data, each respective said first portion and said further portion comprising a respective digital data sequence, the respective digital data sequences being repeated within said first portion of said further portion, respectively, and the digital data sequence for each said further portion of digital data providing a preamble of alternating `1`s and `0`s in a repeating pattern followed by a synchronization pattern, the burst communication means operating in the second mode (i) to detect said synchronization pattern received during one of said receive periods and determine therefrom timing information about the asynchronously transmitted bursts, and then (ii) decode, by means of said timing information, the digital data sequence of said first portion of a subsequent asynchronously transmitted burst to obtain therefrom said digital data for the logical communication channel (D), with such digital data sequence being received in a subsequent receive period.
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23. A telecommunication device for establishing synchronous time-division two-way communication with another device over a radio channel by exchanging radio signals with said other device in alternating bursts carrying digital data such that, during the time-division two-way communication, reception of one of said alternating bursts from said other devices is completed before transmission of the next of said alternating bursts by said telecommunication device is begun,
said telecommunication device comprising: -
burst transmission means for transmitting bursts of digital data; and control means for controlling the burst transmission means to operate in a first mode in which the burst transmission means transmits a burst of said alternating bursts and then ceases transmission to allow a burst of said alternating bursts to be received from said other device, and a second mode in which the burst transmission means transmits asynchronously a burst other than said alternating bursts, said asynchronously transmitted burst comprising one or more first portions of digital data for a logical communication channel (D), which carries signalling data such as device identification codes, followed by one or more further portions of digital data, and then ceases transmission for a period to allow a reply from said other device to be received, each respective said first portion and said further portion of digital data comprising a respective digital data sequence, the respective digital data sequences being repeated within said first portion or said further portion, respectively, and the digital data sequence for each said further portion of digital data providing a preamble of alternating `1`s and `0`s in a repeating pattern followed by a synchronization pattern to enable said other device to determine timing information about the burst when it receives it.
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24. A telecommunication device for establishing time-division two-way communication with another device over a radio channel by exchanging radio signals in alternating bursts carrying digital data such that, during the time-division two-way communication, reception of one of said alternating bursts from said other device is completed before transmission of the next of said alternating bursts by said telecommunication device is begun,
said telecommunication device comprising: -
burst format means for (a) arranging digital data into bursts for transmission and (b) obtaining digital data from received bursts in accordance with a format of digital data selected from a plurality of predetermined formats including a two-channel format which specifies that a burst includes information both for a first logical communication channel (D), which carries signalling data, such as device identification codes and instructions between the telecommunication device and said other device, and for a second logical communication channel (B), which carries data to be communicated between the telecommunication device and said other device, such as digitally encoded speech, said two channel format being chosen from a predefined group of alternative formats of said two-channel format, said predefined group comprising first and second formats which differ from each other in the channel carried in each burst; and control means for choosing which of said predefined group of alternative formats of said two-channel format should be included in said plurality of predetermined formats, said control means choosing said two-channel format from said predefined group of alternative formats of said two-channel format following transmission of data to said other device relating to the choosing of the two-channel format and reception of data from said other device relating to the choosing of the two-channel format, the control means determining said data to be transmitted based on the performance capabilities of the telecommunication device and choosing said two-channel format based on said data received from said other device. - View Dependent Claims (25)
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Specification