EP0189695B1
Expired / Lapsed
EP
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Radio-communication system with slow frequency hopping and composite sequences allocation protocol
Assignee: Ministère des Postes Télégraphes et Téléphones
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Filing: 1985-12-17
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Granted: 1989-09-20
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Expires: 2005-12-17
Abstract
No abstract record available.
Inventors
- 👤 Michel Mouly
- 👤 Didier Verhulst
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 11:15
CPC Classifications
H; H04; H04W; H04W16/00; H04W16/02; H04W16/12; H04B; H04B7/00; H04B7/24; H04B7/26; H04B7/2628; H04B7/2634; H04L; H04L1/00; H04L1/004; H04L1/0041; H04L1/0056; H04L1/0057
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
210 words
Radiocommunications system based on a code division multiple access system with slow frequency hopping (CDMA/SFH), this system enabling bilateral communication between fixed stations and mobile stations, each fixed station covering one or more cells, the information transmitted by such a system being digitally encoded by modulating a carrier whose frequency successively occupies various freuqency levels according to a sequence having a specified frequency hopping law, these frequencies being selected from a group of frequencies common to the entire system, one sequence being used to identify the signal transmitted and received by a mobile station, this system being such that for a sequence allocated to a mobile station in a cell, the sequences allocated, in this cell or in a group of adjacent cells including this cell, to other mobile stations have, with the sequence in question, a zero collision rate, this system being characterized in that at least one sequence allocated in the other cells, i.e. in the cells which are neither the cell in question, not the cells adjacent to the cell in question, has, with the sequence in question, a collision rate which is not zero but which is less than or equal to 1/M where M is the number of frequencies actually used in the two sequences.
Claim 2
Dependent Claim
210 words
Radiocommunications system based on a code division multiple access system with slow frequency hopping (CDMA/SFH), this system enabling bilateral communication between fixed stations and mobile stations, each fixed station covering one or more cells, the information transmitted by such a system being digitally encoded by modulating a carrier whose frequency successively occupies various freuqency levels according to a sequence having a specified frequency hopping law, these frequencies being selected from a group of frequencies common to the entire system, one sequence being used to identify the signal transmitted and received by a mobile station, this system being such that for a sequence allocated to a mobile station in a cell, the sequences allocated, in this cell or in a group of adjacent cells including this cell, to other mobile stations have, with the sequence in question, a zero collision rate, this system being characterized in that at least one sequence allocated in the other cells, i.e. in the cells which are neither the cell in question, not the cells adjacent to the cell in question, has, with the sequence in question, a collision rate which is not zero but which is less than or equal to 1/M where M is the number of frequencies actually used in the two sequences.
Claim 3
Dependent Claim
93 words
System according to Claim 1, characterized in that the cells are organized in groups called patterns of reutilization, each cell being able to be referenced by the position which it occcupies in a pattern, the maximum number of frequencies allocated to a cell being equal to P, and in that the sequences utilized in the cells of different positions have a zero collision rate and the sequences utilized in the cells of the same position have a collision rate which is not zero but which is less than or equl to 1 /P.
Claim 4
Dependent Claim
41 words
Radiocommunications system according to Claim 1, characterized in that from digital data signals, encoded signals are formed having a certain redundancy rate, these encoded signals being organized as data blocks, the data of one block being distributed over several frequency levels.
Claim 5
Dependent Claim
16 words
System according to Claim 3, characterized in that the redundancy rate is between 2 and 3.
Claim 6
Dependent Claim
43 words
System according to Claim 1, characterized in that it comprises a means of detecting the periods of inactivity of the mobile stations and/or of the fixed stations and a means of suppressing the transmission of freuquency levels corresponding to these periods of inactivity.
Claim 7
Dependent Claim
22 words
System according to Claim 2, characterized in that the number of cells forming a pattern is less than or equal to 4.
Claim 8
Dependent Claim
36 words
System according to Claim 2, characterized in that the configuration of the cellular patterns and the rules of allocation of sequences of frequencies in the various cells are adaptable to the operating conditions of the system.
Claim 9
Dependent Claim
34 words
System according to Claim 1, characterized in that it utilizes additional sequences each having, with any other sequence of the system, a collision rate of less than 1/M', where M' is less than M.
Claim 10
Dependent Claim
23 words
System according to Claim 1, characterized in that it utilizes several sets of sequences being utilized in an incomplete way and time multiplexed.
Claim 11
Dependent Claim
30 words
System according to Claim 8, characterized in that the additional sequences intended for signalling and/or for date are allocated by the fixed stations to the mobile stations which request them.
Claim 12
Dependent Claim
23 words
System according to Claim 8, characterized in that the additional sequences intended for signalling and/or for data are pre-allocated to the mobile stations.
Claim 13
Dependent Claim
41 words
System according to Claim 1, characterized in that it also works according to the time division multiple access protocol (TDMA) enabling several mobile stations in communication with the same fixed station to use the same sequence but with separate frequency levels.
Claim 14
Dependent Claim
36 words
System according to Claim 12, characterized in that each fixed station includes several sectorial antennas, the station transmitting in a single sector at any one time and receiving in a single sector at any one time.
Claim 15
Dependent Claim
27 words
System according to Claim 12, characterized in that each mobile station does not work in the transmission mode and in the reception mode at the same time.
Claim 16
Dependent Claim
34 words
System according to Claim 14, characterized in that each mobile station works according to a cycle including a transmission stage, a reception stage and a rest stage, the latter being used for changing frequency.
Claim 17
Dependent Claim
28 words
System according to any of Claims 13 to 15, characterized in that pattern of re-utilization is a pattern of three cells which are identified with the three sectors.
References Cited (Backward Citations)
No citation records indexed.
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