Digital radio transmission system for a cellular network, using the spread spectrum method
First Claim
1. Digital radio transmission system for a network of cells using a phase-coded spread spectrum technique, in which spectrum spreading of a transmitted information carrying signal takes place by multiplication of the information carrying signal with an auxiliary function and despreading of a received information carrying signal takes place by using this auxiliary function, comprising several user stations within a cell, each having a transmitter, a receiver for multipath reception and a control unit and further comprising a base station with a plurality of transmitter-receivers and a base control unit, characterized in that(a) exactly one set of several sets of spreading sequences used as the auxiliary function is allocated to each cell and an inverse of the one spreading sequence set is used as the despreading sequence;
- (b) paired sequences of different sets have absolute values for normalized periodic cross-correlation functions which are less than one for all values;
(c) in sequences with a set, values for paired cross-correlation functions are minimized around a zero point of the paired cross-correlation functions;
(d) data synchronous generation of the transmitted information carrying signals take place in the base stations for all simultaneous connections; and
(e) a data clock of a received information carrying signal is sued as a data clock of a transmitted information carrying signal within a given user station.
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Accused Products
Abstract
A base station (BS) and mobile user stations (MS) each with a transmitter (S), a receiver (E) for multipath reception and a control unit (ST) are provided in each cell. Exactly one set of several sequence sets of the auxiliary function used for spectrum spreading is allocated to each cell. Sequences of several sets in pairs have the property that the absolute values of the normalized periodic cross-correlation functions are much smaller than one and for sequences within a set the cross-correlation function in pairs is optimally small around the zero point. Data synchronous generation of the transmission signals takes place in the base station (BS) for all simultaneous connections and the data clock of the received signal is used as data clock of the transmission signal of the user station (MS).
Application for digital data transmission in buildings and local areas for the configuration of a so called cordless LAN are considered.
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Citations
23 Claims
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1. Digital radio transmission system for a network of cells using a phase-coded spread spectrum technique, in which spectrum spreading of a transmitted information carrying signal takes place by multiplication of the information carrying signal with an auxiliary function and despreading of a received information carrying signal takes place by using this auxiliary function, comprising several user stations within a cell, each having a transmitter, a receiver for multipath reception and a control unit and further comprising a base station with a plurality of transmitter-receivers and a base control unit, characterized in that
(a) exactly one set of several sets of spreading sequences used as the auxiliary function is allocated to each cell and an inverse of the one spreading sequence set is used as the despreading sequence; -
(b) paired sequences of different sets have absolute values for normalized periodic cross-correlation functions which are less than one for all values; (c) in sequences with a set, values for paired cross-correlation functions are minimized around a zero point of the paired cross-correlation functions; (d) data synchronous generation of the transmitted information carrying signals take place in the base stations for all simultaneous connections; and (e) a data clock of a received information carrying signal is sued as a data clock of a transmitted information carrying signal within a given user station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification