Preamble based selection diversity in a time division multiple access radio system
First Claim
1. An antenna selection system for use in a radio receiver having a plurality of alternatively connectable antenna channels for receiving data bursts each having a preamble, a sync word and a data field, the antenna selection system comprising:
- a) means for receiving an indication that the sync word has been received in a previous burst;
b) timing means for measuring forward in time from reception of the sync word of the previous burst to provide an estimate of the beginning of the preamble of a present burst;
c) selection means for controlling which of the plurality of antenna channels is connected and for making performance measurements, the selection means connecting the plurality of antenna channels in turn and making a performance measurement for each antenna channel and after all the performance measurements are made the selection means connecting to the receiver the antenna channel with the best performance measurement, the first performance measurement being made during a period having a start time related to the estimate of the beginning of the preamble of the present burst.
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Accused Products
Abstract
A selection diversity system and method for use in a TDMA (time division multiple access) radio system, particularly suited for DECT (Digital Enhanced Cordless Telephone) applications, in which a single receiver makes a performance measurement on each of two antennas in sequence during the beginning of a received data burst, the beginning of the burst being determined by a timing signal fed back from a previous burst. A slicing level used in the receiver to perform threshold detection is continuously improved during the measurements of the two antennas, but held while switching between the antennas. The previously unused antenna is measured first to minimize the likelihood of having to perform two antenna switches.
47 Citations
28 Claims
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1. An antenna selection system for use in a radio receiver having a plurality of alternatively connectable antenna channels for receiving data bursts each having a preamble, a sync word and a data field, the antenna selection system comprising:
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a) means for receiving an indication that the sync word has been received in a previous burst; b) timing means for measuring forward in time from reception of the sync word of the previous burst to provide an estimate of the beginning of the preamble of a present burst; c) selection means for controlling which of the plurality of antenna channels is connected and for making performance measurements, the selection means connecting the plurality of antenna channels in turn and making a performance measurement for each antenna channel and after all the performance measurements are made the selection means connecting to the receiver the antenna channel with the best performance measurement, the first performance measurement being made during a period having a start time related to the estimate of the beginning of the preamble of the present burst. - View Dependent Claims (2, 3, 4, 5)
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6. An antenna selection system for use in a time division multiple access radio receiver having first and second alternatively connectable antenna channels for receiving data bursts each having a preamble, a sync word and a data field, the antenna selection system comprising:
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a) means for receiving an indication that the sync word has been received in a previous burst; b) timing means for measuring forward in time from reception of the sync word of the previous burst to provide an estimate of the beginning of the preamble of a present burst; c) selection means for controlling which antenna channel is connected and for making performance measurements, the selection means connecting the first antenna channel and making a performance measurement for the first antenna channel during a period having a start time related to the estimate of the beginning of the preamble of the present burst, and subsequently connecting the second antenna channel and making a performance measurement for the second antenna channel, the selection means reconnecting the first antenna channel if the first performance measurement is better than the second performance measurement. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A TDMA radio receiver for receiving data bursts each having a preamble, a sync word and a data field, the receiver comprising:
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a) first and second alternatively connectable antenna channels; b) a synchronization circuit which generates a signal when the sync word has been received; c) timing means for measuring forward in time from reception of the sync word of a previous burst to provide an estimate of the beginning of the preamble of a present burst; d) selection means for controlling which antenna channel is connected and for making performance measurements, the selection means connecting the first antenna channel and making a performance measurement for the first antenna channel during a period having a start time related to the estimate of the beginning of the preamble of the present burst, and subsequently connecting the second antenna channel and making a performance measurement for the second antenna channel, the selection means reconnecting the first antenna channel if the first performance measurement is better than the second performance measurement. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. An antenna selection method for use in a time division multiple access radio receiver having first and second alternatively connectable antenna channels for receiving data bursts each having a preamble, a sync word and a data field, the antenna selection method comprising the steps of:
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a) determining when the sync word for the previous burst has been received; b) measuring forward in time from the reception of the sync word of a previous burst to provide an estimate of the beginning of the preamble of a present burst; c) connecting the first antenna channel; d) measuring a first performance measurement for the first antenna channel during a first time interval having a start time related to the estimate of the beginning of the preamble of the present burst; e) connecting the second antenna channel during a second time interval following said first time interval; f) measuring a second performance measurement for the second antenna channel during a third time interval following said second time interval; g) comparing the first performance measurement and the second performance measurement to determine which performance measurement is better; and h) reconnecting the first antenna channel if the first performance measurement is better. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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Specification