Threshold detector for digital radio transmission systems, devices comprising a threshold detector of this kind and corresponding utilization

Claim 2

Threshold detector for a digital signal transmission system using a transmission channel, in particular for transmission to mobiles, comprising: means for calculating a set of coefficients f n belonging to a group comprising of a set of coefficient c n expressing a correlation between a first series of digital samples x n received by a receiver and a second series of reference digital samples p n know to said receiver, in order to acquire synchronization of the system, and a set of coefficient h n of an estimate of an impulse response of said transmission channel, when said system is already synchronized; and means for calculating a decision variable A such that: ##EQU39## where L and N are predetermined integers.

Claim 3

Threshold detector according to claim 1 wherein L is a value representative of the length of said transmission channel.

Claim 4

Threshold detector according to claim 1 wherein N is a value greater than or equal to at least one of the following: the length of said first and second series of samples; a value representative of a rate of variation of said transmission channel; the length of a data burst; a spreading factor or bandwith expansion factor of a direct sequence code division multiple access signal.

Claim 5

Threshold detector according to claim 1 wherein said first series of samples received corresponds to a pilot code of a direct sequence code division multiple access signal, and further comprising means for comparing said decision variable A to a predetermined threshold T supplying a decision indication on the basis of said comparison, said predetermined threshold T being equal to: ##EQU40## where (S/N) min is the minimum signal to noise ratio defining the range of operation ((S/N) min , +∞) of said transmission system.

Claim 6

Device for acquiring synchronization of a direct sequence code division multiple access spread spectrum signal, comprising: a threshold detector for a digital signal transmission system using a transmission channel, in particular for transmission to mobiles, said threshold detector comprising means for calculating PG,26 a set of coefficients f n belonging to a group comprising a set of coefficients c n expressing a correlation between a first series of digital samples x n received by a receiver and a second series of reference digital samples p n known to said receiver, in order to acquire synchronization of the system, and a set of coefficients h n of an estimate of an impulse response of said transmission channel, when said system is already synchronized, which detector further comprises means for calculating a decision variable A such that: ##EQU41## where L and N are predetermined integers, said threshold detector supplying a synchronization looking indication.

Claim 7

Device for acquiring synchronization of a direct sequence code division multiple access spread spectrum signal, comprising: a threshold detector for a digital signal transmission system using a transmission channel, in particular for transmission to mobiles, said threshold detector comprising means for calculating PG,26 a set of coefficients f n belonging to a group comprising a set of coefficients c n expressing a correlation between a first series of digital samples x n received by a receiver and a second series of reference digital samples p n known to said receiver, in order to acquire synchronization of the system, and a set of coefficients h n of an estimate of an impulse response of said transmission channel, when said system is already synchronized, which detector further comprises means for calculating a decision variable A such that: ##EQU41## where L and N are predetermined integers, said threshold detector supplying a synchronization looking indication.

Claim 8

Device for estimating an impulse response of a transmission channel, and for calculating a set of coefficients h n of a channel estimate, comprising: a threshold detector for a digital signal transmission system using a transmission channel, in particular for transmission to mobiles, said threshold detector comprising means for calculating a set of coefficients f n belonging to a group comprising a set of coefficients c n expressing a correlation between a first series of digital samples x n received by a receiver and a second series of reference digital samples p n known to said receiver, in order to acquire synchronization of the system, and a set of coefficients h n of an estimate of the impulse response of said transmission channel, when said system is already synchronized, and means for calculating a decision variable A such that: ##EQU42## where L and N are predetermined integers, which device further comprises means for correcting said set of coefficients h n according to at least one threshold which is variable according to said decision variable.

Claim 9

Device for estimating an impulse response of a transmission channel, and for calculating a set of coefficients h n of a channel estimate, comprising: a threshold detector for a digital signal transmission system using a transmission channel, in particular for transmission to mobiles, said threshold detector comprising means for calculating a set of coefficients f n belonging to a group comprising a set of coefficients c n expressing a correlation between a first series of digital samples x n received by a receiver and a second series of reference digital samples p n known to said receiver, in order to acquire synchronization of the system, and a set of coefficients h n of an estimate of the impulse response of said transmission channel, when said system is already synchronized, and means for calculating a decision variable A such that: ##EQU42## where L and N are predetermined integers, which device further comprises means for correcting said set of coefficients h n according to at least one threshold which is variable according to said decision variable.

Claim 10

Device for estimating a signal to noise ratio of a transmission channel, and for calculating a set of coefficients h n of an estimate of the channel, comprising: a threshold detector for a digital signal transmission system using a transmission channel, in particular for transmission to mobiles, said threshold detector comprising means for calculating a set of coefficients f n belonging to a group comprising a set of coefficients c n expressing a correlation between a first series of digital samples x n received by a receiver and a second series of reference digital samples p n known to said receiver, in order to acquire synchronization of the system, and a set of coefficients h n of an estimate of an impulse response of said transmission channel, when said system is already synchronized, and means for calculating a decision variable A such that: ##EQU43## where L and N are predetermined integers, which device further comprises means for calculating an estimate of said signal to noise ratio as: ##EQU44##

Claim 11

Device for estimating a signal to noise ratio of a transmission channel, and for calculating a set of coefficients h n of an estimate of the channel, comprising: a threshold detector for a digital signal transmission system using a transmission channel, in particular for transmission to mobiles, said threshold detector comprising means for calculating a set of coefficients f n belonging to a group comprising a set of coefficients c n expressing a correlation between a first series of digital samples x n received by a receiver and a second series of reference digital samples p n known to said receiver, in order to acquire synchronization of the system, and a set of coefficients h n of an estimate of an impulse response of said transmission channel, when said system is already synchronized, and means for calculating a decision variable A such that: ##EQU43## where L and N are predetermined integers, which device further comprises means for calculating an estimate of said signal to noise ratio as: ##EQU44##

Claim 12

Device for estimating a signal to noise ratio for any of the following applications: equalizer activation control; time division multiple access signal equalizer decision weighing; code division multiple access signal despreading activation control; signal transmit power control, of a device for estimating the signal to noise ratio of a transmission channel, and for calculating a set of coefficients h n of an estimate of the channel, comprising: a threshold detector for a digital signal transmission system using a transmission channel, in particular for transmission to mobiles, said threshold detector comprising means for calculating a set of coefficients f n belonging to a group comprising a set of coefficients c n expressing a correlation between a first series of digital samples x n received by a receiver and a second series of reference digital samples p n known to said receiver, in order to acquire synchronization of the system, and a set of coefficients h n of an estimate of an impulse response of said transmission channel, when said system is already synchronized, and means for calculating a decision variable A such that: ##EQU45## where L and N are predetermined integers,. which device further comprises means for calculating an estimate of said signal to noise ratio as: ##EQU46##

Claim 13

Device for estimating a signal to noise ratio for any of the following applications: equalizer activation control; time division multiple access signal equalizer decision weighing; code division multiple access signal despreading activation control; signal transmit power control, of a device for estimating the signal to noise ratio of a transmission channel, and for calculating a set of coefficients h n of an estimate of the channel, comprising: a threshold detector for a digital signal transmission system using a transmission channel, in particular for transmission to mobiles, said threshold detector comprising means for calculating a set of coefficients f n belonging to a group comprising a set of coefficients c n expressing a correlation between a first series of digital samples x n received by a receiver and a second series of reference digital samples p n known to said receiver, in order to acquire synchronization of the system, and a set of coefficients h n of an estimate of an impulse response of said transmission channel, when said system is already synchronized, and means for calculating a decision variable A such that: ##EQU45## where L and N are predetermined integers,. which device further comprises means for calculating an estimate of said signal to noise ratio as: ##EQU46##