Patent ID: 6400705
Filing Date: 2002-06-04
Classification: H04J,H04N

Abstract:
A method to determine an access frequency band in a communication access network, said communication access network including a plurality of terminals (T11, T12, T13, . . . , T31, . . . ) and a head-end (HE) which includes a plurality of transceivers (TRX1, TRX2, TRX3, . . . ), said head-end (HE) being downstream coupled to each one of said plurality of terminals (T11, T12, T13, . . . , T31, . . . ) via a downstream common link (Lc) and a tree-like distributive network, each one of said plurality of transceivers (TRX1, TRX2, TRX3, . . . ) providing to a combiner (COMB) included in said head-end (HE) one of a plurality of downstream signals (Sd1, Sd2, Sd3, . . . ) in one of a plurality of frequency bands (CH1, CH2, CH3, . . . ) that are associated by means of a predetermined first association to said plurality of transceivers (TRX1, TRX2, TRX3, . . . ), said plurality of downstream signals (Sd1, Sd2, Sd3, . . . ) being together combined by said combiner (COMB) into a downstream modulated signal (S-MOD), said downstream modulated signal (S-MOD) being broadcasted from said head-end (HE) to said plurality of terminals (T11, T12, T13, . . . , T31, . . . ), a first one (T12) of said plurality of terminals being upstream coupled to at least one of said plurality of transceivers (TRXrec1, TRXrec2, . . . ) via a common upstream link and at least one upstream sublink, said access frequency band being one of said plurality of frequency bands (CH1, CH2, CH3, . . . ) to be used by said first terminal (T12) to filter, out of said downstream modulated signal (S-MOD), one of said downstream signals provided by an access transceiver, said access transceiver being one of said plurality of transceivers (TRX1, TRX2, TRX3, . . . ), in order to establish a communication between said access transceiver and said first terminal (T12), characterized in that said method includes the steps of:a) choosing by said first terminal (T12) out of said plurality of frequency bands (CH1, CH2, CH3, . . . ) a start frequency band (CHst); b) determining by said first terminal (T12) with said start frequency band (CHst) and according to a predetermined second association, an upstream frequency band (CHu), said upstream frequency band (CHu) being one of a plurality of upstream frequency bands (CHu1, CHu2, Chu3, . . . ) whereof each one is associated by means of said predetermined second association to one of said plurality of frequency bands (CH1, CH2, CH3, . . . ); c) transmitting by said first terminal (T12) within said upstream frequency band (CHu) an access request signal (AR(T12)) to said at least one transceiver (TRXrec1, TRXrec2, . . . ) to which said first terminal (T12) is coupled; d) filtering, by said at least one transceiver (TRXrec1, TRXrec2, . . . ) to which said first terminal (T12) is coupled, incoming signals so as to provide a filtered signal; e) in the event that said upstream frequency band (CHu) of said first terminal (T12) corresponds to an upstream frequency band (CHu1) used by said at least one transceiver (TRXrec1, TRXrec2 . . . ) to which said first terminal (T12) is coupled, then said filtered signal corresponds to said access request signal (AR(T12)) and said at least one transceiver (TRXrec1, TRXrec2, . . . ) to which said first terminal (T12) is coupled constitutes said access transceiver, confirming to said first terminal (T12) by said head-end (HE) that said start frequency band (CHst) constitutes said access frequency band; and f) in the event that after a predetermined time from sending said access request signal (AR(T12)) without receiving said confirmation of said step e), repeating said steps of said method with another start frequency band (CHstâ€²).