Direct-sequence spread spectrum communication system, a primary radio station, and a secondary radio station

• US 5,878,076 A
• Filed: 05/13/1996
• Issued: 03/02/1999
• Est. Priority Date: 05/12/1995
• Status: Expired due to Term

• Current Assignee: Koninklijke Philips N.V., US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Siedenburg, Kurt
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US08/645,441
• Time in Patent Office: 1,023 Days
• Field of Search: 375/200, 375/206, 375/354, 455/500, 327/164, 364/717
• US Class Current: 375/141
• CPC Class Codes: H04B 1/70753 Partial phase search
• CPC Class Codes: H04B 1/7077 Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence

Abstract

Known are direct-sequence spread spectrum systems (1) such as CDMA mobile radio systems applying short pseudo-noise sequences for encoding and decoding of data. A DS-SS communication system is provided in which less pseudo-noise sequences are used while at the same time providing efficient locking at the receiver side. To this end, a majority of the channels (BCH, PCH, AGCH, TCH, ACCH) in a cell (Z1, Z2) of a mobile radio system (1) share one long pseudo-noise sequence (PNL). At reception side, in a mobile radio station (MS1, MS2) or the like, efficient calculation of current sequence phases for current received channels is achieved by applying vector-matrix calculations to a received sequence state (x_i) and received sequence offset (ofset) that are transmitted by a base station (BS1, BS2). The vector-matrix calculations apply precalculated and stored sequence offset transformation matrices (A).

Claims

1. A direct-sequence spread spectrum communication system comprising at least one primary radio station and a plurality of secondary radio stations, the primary radio station and the secondary radio stations being arranged for communication with each other via control channels and traffic channels, characterized in that at least in a cell at least a majority of the channels share at least one long pseudo-noise sequence, generated by at least one linear feedback shift register, the channels being distinguishable within the at least one long pseudo-noise sequence, and in that for locking on a current channel using a long pseudo-noise sequence, a phase of the current channel within the long pseudo-noise sequence at receiver side is derived from state information about the linear feedback shift register transmitted via a control channel.

2. A direct-sequence spread spectrum communication system according to claim 1, wherein the state information is a previous state of the linear feedback shift register, and the state of the linear feedback shift register for the current channel is determined by transforming the previous state to the current state using a stored transformation matrix.

3. A direct-sequence spread spectrum communication system according to claim 1, wherein the primary station determines a future state for a given channel with a predetermined offset from a state of the linear feedback shift register for the channel by transforming the state to the future state using the stored transformation matrix, the future state being transmitted as the state information.

4. A direct-sequence spread spectrum communication system according to claim 1, wherein the primary station determines an intermediate state for a given channel with a predetermined offset from a state of the linear feedback shift register for the channel by transforming the state to the intermediate state using the stored transformation matrix, the intermediate state being transmitted to the secondary station, and at the side of the secondary station the state of the linear feedback shift register for the current channel is determined by using the intermediate state directly and/or by transforming the intermediate state using the stored transformation matrix.

5. A direct-sequence spread spectrum communication system according to claim 1, wherein the state information is an offset with respect to a fixed reference state of the linear feedback shift register, and the contents of the linear feedback shift register of the current channel is determined from the received offset and a plurality of stored transformation matrices.

6. A direct-sequence spread spectrum communication system according to claim 1, wherein the locking on the current channel is a coarse locking, and a fine locking is achieved by loading a correlator in the secondary station with a contents of the linear feedback shift register corresponding to the phase of the current channel and correlating the loaded correlator with received chips.

7. A primary radio station for use in a direct-sequence spread spectrum communication system, which primary station comprises means for communicating with a plurality of secondary radio stations via control channels and traffic channels, characterized in that for at least a majority of the channels the primary station shares at least one long pseudo-noise sequence, generated by at least one linear feedback shift register, the channels being distinguishable within the at least one pseudo-noise sequence, and in that the primary station is arranged for transmitting state information about the linear feedback shift register to the secondary stations via a control channel, the primary station using a short pseudo-noise sequence for encoding the state information so that the secondary station can decode received data in a current channel using the long pseudo-noise sequence.

8. A secondary radio station for use in a direct-sequence spread spectrum system, which secondary radio station comprises means for communicating with a primary radio station via control channels and traffic channels, characterized in that the secondary radio station is arranged for receiving from the primary station at least a majority of the channels using at least one long pseudo-noise sequence generated by at least one linear feedback shift register, the channels being distinguishable within the at least one pseudo-noise sequence, and in that the secondary radio station is arranged for locking on a current channel using the long pseudo-noise sequence by deriving a phase of the current channel from state information about the linear feedback shift register received from the primary station via a control channel.

9. A direct sequence spread spectrum communication system comprising at least one primary radio station and a plurality of secondary stations, the primary and secondary stations being configured to communicate with each other via control channels and traffic channels, in which system the at least one primary station is configured to generate at least one long pseudo-noise sequence for shared use by at least a majority of the control and traffic channels, and to transmit state information of a current channel represented by a part of the long pseudo-noise sequence to the secondary radio stations, the secondary radio stations being configured to distinguish channels represented by different parts of the long pseudo-noise sequence using the state information received from the secondary radio station.