EP0219085B1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A spread spectrum wireless pbx
Assignee: AT&T Inc
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Filing: 1986-10-11
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Granted: 1992-06-03
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Expires: 2006-10-11
Abstract
No abstract record available.
Inventors
- 👤 Mohsen Kavehrad
- 👤 Peter John Mclane
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 13:12
CPC Classifications
H; H04; H04W; H04W84/00; H04W84/02; H04W84/10; H04W84/16; H04B; H04B1/00; H04B1/69; H04B1/707; H04B1/709; H04B1/7093; H04B7/00; H04B7/24; H04B7/26; H04Q; H04Q11/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
187 words
A wireless local communication system CHARACTERIZED BY a plurality of separate local user transceivers (10i), each local user transceiver comprising a transmitter (11) and a receiver (12) for respectively transmitting and receiving uniquely encoded direct sequence spread spectrum radio signals; and a central Private Branch Exchange (14) (PBX) comprising a plurality of PBX transceivers (15i), each PBX transceiver (a) being matched to a separate one of the plurality of local user transceivers to provide a separate matched pair of a local user/PBX transceiver and (b) including a separate transmitter (16) and receiver (17), each transceiver of a matched pair of transceivers solely transmitting to and receiving from its matched transceiver direct sequence spread spectrum radio signals which are encoded in a manner unique to said matched pair of transceivers while substantially rejecting transmissions from any non-matched transceiver, and a switching means (18) for interconnecting any one of the plurality of PBX transceivers to any other one of the plurality of PBX transceivers and/or to an external communication network, said switching means being capable of supporting a plurality of simultaneous PBX transceiver-PBX transceiver and PBX transceiver-external network interconnections.
Claim 2
Dependent Claim
128 words
A wireless local communication system according to claim 1 CHARACTERIZED IN THAT the transmitters of each separate matched pair of a local user transceiver and a PBX transceiver comprise means for encoding an input digital bit stream into a unique direct sequence spread spectrum signal using a unique spread spectrum chip sequence for transmission to the receiver of the other transceiver of the matched pair of transceivers, and the receivers of each separate matched pair of a separate local user transceiver and a separate PBX transceiver comprise means for decoding a direct sequence spread spectrum signal received from the other transceiver of the matched pair of transceivers into a recovered digital bit stream using said unique spread spectrum chip sequence used by the transmitter of the matched transceiver.
Claim 3
Dependent Claim
81 words
A wireless local communication system according to claim 2 wherein the transmitter in each local user transceiver is further CHARACTERIZED BY means responsive to call set-up control information including an origination and destination address received at the onset of a call from an associated end user for transmitting said call set-up control information to the central PBX in a direct sequence spread spectrum signal using a second unique spread spectrum chip sequence which is common to all said local user transmitters.
Claim 4
Dependent Claim
74 words
A wireless local communication system according to claim 3, wherein said central PBX is further CHARACTERIZED BY a call set-up receiver which is solely responsive to call set-up control information, including origination and destination addresses, received in the direct sequence spread spectrum signal encoded with the second spread spectrum chip sequence at the onset of a call from any one of said local user transmitters for generating appropriate control signals to the switching means.
Claim 5
Dependent Claim
78 words
A wireless local communication system according to claim 4, wherein the central PBX is further CHARACTERIZED BY control means responsive to control signals indicating origination and destination addresses from either said call set-up receiver or the external communications network for (a) determining whether an open link exists through the switching means to interconnect the indicated origination and destination addresses, and (b) upon finding an available open link, closing said open link to connect the origination and destination users.
Claim 6
Dependent Claim
131 words
A wireless local communications system according to claims 2 and 4, wherein each of the receivers is CHARACTERIZED BY a surface acoustic wave (SAW) matched filter correlator, responsive to a direct sequence spread spectrum signal received via multiple paths, for providing as an output signal only the received signals encoded with a predetermined spread spectrum chip sequence associated with said receiver and substantially rejecting all other direct sequence spread spectrum signals; and an integration and latching means responsive to the demodulated signal output of said SAW matched filter correlator and to a clock pulse generated from output of said SAW matched filter correlator correlator, which integrates said demodulated signal output of said SAW matched filter over the period of each clock pulse, gating out a single signal pulse per clock period.
Claim 7
Dependent Claim
135 words
A wireless local communication system according to claims 2 and 4, wherein each of the receivers is CHARACTERIZED BY a receiver subsection for receiving direct sequence spread spectrum signals which propagate via multiple paths between transceivers of the system, the receiver subsection including: a surface acoustic wave (SAW) matched filter correlator, responsive to a direct sequence spread spectrum signal received via multiple paths, for providing as an output signal only the received signals encoded with a predetermined spread spectrum chip sequence associated with said receiver and substantially rejecting all other direct sequence spread spectrum signals; and path select means responsive to an output signal from said SAW correlator for providing as an output signal only the strongest signal received from one of the multiple paths and suppressing weaker signals received in the other multiple paths.
Claim 8
Dependent Claim
71 words
A wireless local communication system according to claim 7 wherein each of the receivers is further CHARACTERIZED BY a plurality of said receiver subsections disposed in a parallel relationship to each other for providing diversity reception of the multiple path direct sequence spread spectrum signals; and means responsive to the output signals from the path select means of the plurality of receiver subsections for selecting the strongest of said output signals.
Claim 9
Dependent Claim
48 words
A wireless local communication system according to claim 2, wherein each local user transmitter and PBX transmitter is CHARACTERIZED BY An error correction encoding means responsive to an incoming information bit stream to be transmitted for encoding said incoming information bit stream with a predetermined error correction code.
Claim 10
Dependent Claim
55 words
A wireless local communication system according to claim 9 wherein each of the local user receivers and PBX receivers is CHARACTERIZED BY an error correction decoder responsive to an information bit stream from the receiver decoding means for decoding the information bit stream with a predetermined error correction code to detect and correct errors therein.
References Cited (Backward Citations)
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