Patent US4466888A successfully refreshed from Google Patents.
EP0335846A1
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Cellular digital mobile radio system with plural base station transmitters, and method of transmitting information in such a system
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1989-02-08
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Granted: —
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Expires: 2009-02-08
Abstract
Abstract The invention relates to a cellular digital mobile radio system including base stations (B m , B n ) and mobile stations MS₁, MS₂) with transmitters and receivers. The invention also relates to a method of transmitting message information digitally between mobile and base stations in such a system. In accordance with the invention, at least two base station transmitters (B ma , B mb , B na , B nb ) at a given transmitting distance from each other are assigned to each of certain cells (C m , C n ) within a restricted geographical area. The base station transmitters which are assigned to the same cell transmit digitally modulated radio signals within the same frequency range at least partially simultaneously to the mobile stations of the cell. The radio signals from different base stations transmitters associated with the same cell are digitally modulated with the same message information to the mobile stations in the cell. Different base station transmitters (9A, 9B) preferably transmit the digitally modulated radio signals with the same message information to a given mobile station with a given mutual transmission time shift. Here, the transmission time shift is selected individually for each mobile station, such that corresponding digitally modulated radio signals with the same message information to a given mobile station from different base station transmitters arrive practically simultaneously at the mobile station.
Inventors
- 👤 Alex Krister Raith
- 👤 Jan Erik Uddenfeldt
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 03:16
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/65; H04H20/67; H04B; H04B7/00; H04B7/24; H04B7/26; H04B7/2625; H04W; H04W88/00; H04W88/08
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
298 words
A method in a cellular mobile radio system, of transmitting message information digitally between mobile radio stations (MS₁, MS₂) and base stations (BS, BX) associated with the cells (C1, C2,....), radio signals with digital modulation in correspondence with the message information being transmitted and received by transmitters and receivers in the mobile and base stations, where the digital modulation of the radio signals transmitted from the base stations is reconstructed in the mobile stations from received radio signals with the aid of equalizers, characterised in that to mobile stations within one of a plurality of cells within a restricted area there are transmitted digitally modulated signals with the same information from at least two base station transmitters (9A or B ma or B na , 9B or B mb or B nb ) at a given transmitting distance from each other, these digitally modulated radio signals being transmitted at least partially simultaneously and within the same frequency range from both the transmitters of the base stations, in that on transmission of message information the digital modulation of the radio signals is changed with modulation time intervals, said modulation time intervals being shorter than the time for the radio signals to propagate a distance which is just as long as the greatest transmitting distance (21) between two base station transmitters (9A, 9B) associated with the same cell in the area, in that for reconstructing the digital modulation there are utilised in the mobile station radio signals received during a reception time interval, said reception time interval being at least equally as long as the time it takes for signals to propagate a distance which is just as long as the greatest transmitting distance (21) between two base station transmitters (9A, 9B) associated with the same cell in the area.
Claim 2
Independent Claim
298 words
A method in a cellular mobile radio system, of transmitting message information digitally between mobile radio stations (MS₁, MS₂) and base stations (BS, BX) associated with the cells (C1, C2,....), radio signals with digital modulation in correspondence with the message information being transmitted and received by transmitters and receivers in the mobile and base stations, where the digital modulation of the radio signals transmitted from the base stations is reconstructed in the mobile stations from received radio signals with the aid of equalizers, characterised in that to mobile stations within one of a plurality of cells within a restricted area there are transmitted digitally modulated signals with the same information from at least two base station transmitters (9A or B ma or B na , 9B or B mb or B nb ) at a given transmitting distance from each other, these digitally modulated radio signals being transmitted at least partially simultaneously and within the same frequency range from both the transmitters of the base stations, in that on transmission of message information the digital modulation of the radio signals is changed with modulation time intervals, said modulation time intervals being shorter than the time for the radio signals to propagate a distance which is just as long as the greatest transmitting distance (21) between two base station transmitters (9A, 9B) associated with the same cell in the area, in that for reconstructing the digital modulation there are utilised in the mobile station radio signals received during a reception time interval, said reception time interval being at least equally as long as the time it takes for signals to propagate a distance which is just as long as the greatest transmitting distance (21) between two base station transmitters (9A, 9B) associated with the same cell in the area.
Claim 3
Dependent Claim
82 words
A method as claimed in claim 1, characterized in that the digitally modulated radio signals with the same message information are transmitted from the different base station transmitters (B ma , B mb ) to a given mobile station (MS₁, MS₂) with mutually variable transmission time shifting, and in that said transmission time shifting is selected such that it counteracts the differences in propagation time for the signals from the different base station transmitters (9A, 9B) to the mobile station (MS₁, MS₂).
Claim 4
Dependent Claim
91 words
A method as claimed in claim 2, characterized in that the arrival time shift between the digitally modulated radio signals with the same message information from the different base station transmitters is estimated at the mobile station (MS₁, MS₂), in that information on the estimated arrival time shift is transmitted from the mobile station to at least one base station (B m ), and in that the estimated arrival time shift is utilised for selecting transmission time shifting for at least one base station transmitter (B ma , B mb ).
Claim 5
Dependent Claim
61 words
Method as claimed in claim 2, characterized by estimation of the reception time shift between reception by different base station receivers (7A, 7B) of corresponding radio signals with the same message information from the mobile station, and by said reception time shift being utilised for selecting the transmission time shift for corresponding base station transmitters (B na , B nb ).
Claim 6
Dependent Claim
283 words
A cellular mobile radio system with mobile stations (MS₁, MS₂) movable within and between the cells (C1, C2...) and base stations (BS, BS₂...) assigned to the cells for digital transmission of message information, said mobile and base stations including transmitters (6A, 13) and receivers (7A, 15) for radio signals with digital modulation in correspondence with said message information, said transmitters changing the digital modulation with modulation time intervals on transmission of said message information, said receivers including equalizers (16) for reconstructing from received radio signals the digital modulation in transmitted radio signals, characterized in that at least two base station transmitters are assigned to each of at least certain cells (C m C n ) within a limited geographical area, said at least two base station transmitters being disposed a given transmitting distance (L, 2L,...) from each other and transmitting at least partially simultaneously digitally modulated radio signals within the same frequency range with the same message information to the mobile stations within the cell, said at least two base station transmitters having modulation time intervals which are shorter than the time it takes for signals to propagate a distance which is just as long as the greatest transmitting distance (21) between two base station transmitters associated with the same cell in the area, and in that the equalizers in the receivers of the mobile stations are disposed for reconstructing the digital modulation from radio signals received during a time interval which is at least equally as long as the time it takes for radio signals to propagate a distance which is just as great as the greatest transmitting distance between two base station transmitters associated with the same cell in the area.
Claim 7
Dependent Claim
283 words
A cellular mobile radio system with mobile stations (MS₁, MS₂) movable within and between the cells (C1, C2...) and base stations (BS, BS₂...) assigned to the cells for digital transmission of message information, said mobile and base stations including transmitters (6A, 13) and receivers (7A, 15) for radio signals with digital modulation in correspondence with said message information, said transmitters changing the digital modulation with modulation time intervals on transmission of said message information, said receivers including equalizers (16) for reconstructing from received radio signals the digital modulation in transmitted radio signals, characterized in that at least two base station transmitters are assigned to each of at least certain cells (C m C n ) within a limited geographical area, said at least two base station transmitters being disposed a given transmitting distance (L, 2L,...) from each other and transmitting at least partially simultaneously digitally modulated radio signals within the same frequency range with the same message information to the mobile stations within the cell, said at least two base station transmitters having modulation time intervals which are shorter than the time it takes for signals to propagate a distance which is just as long as the greatest transmitting distance (21) between two base station transmitters associated with the same cell in the area, and in that the equalizers in the receivers of the mobile stations are disposed for reconstructing the digital modulation from radio signals received during a time interval which is at least equally as long as the time it takes for radio signals to propagate a distance which is just as great as the greatest transmitting distance between two base station transmitters associated with the same cell in the area.
Claim 8
Dependent Claim
150 words
A mobile radio system as claimed in claim 5, characterized by time measurement means (18) for estimating mutual reception time shifting in a mobile station, (MS₁) between, on the one hand, digitally modulated radio signals transmitted to the mobile station via a base station transmitter (B ma ) for the cell (C m ) where the mobile station is, and, on the other hand, corresponding digitally modulated radio signals transmitted to the mobile station (MS₁) via another base station transmitter (B mb ) for the cell (C m ), and by transmission time shifting means (2A, 2B) for mutually time shifting the transmission times for the base station transmitters (B ma , B mb ) for the same cell (C m ) such that they transmit corresponding digitally modulated radio signals to the mobile station with greater or less mutual transmission time shifting in response to estimated reception time shifting.
Claim 9
Dependent Claim
51 words
A mobile radio system as claimed in claim 6, characterized in that the time measurement means include arrival time comparison means (18), at least in certain mobile station, for comparing the arrival times for corresponding digitally modulated radio signals transmitted from different base station transmitters (9A, 9B) for the same cell.
Claim 10
Dependent Claim
70 words
A mobile radio system as claimed in claim 6, characterized in that the time measurement means include arrival time comparison means (1,9) in the stationary part of the mobile radio system, for comparing the arrival times for digitally modulated radio signals transmitted from a mobile station (MS₂) in a cell (C n ) and received at different base station transceivers (B na , B nb ) associated with the cell.
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