Title of Invention

RUBBER MOULDED GLASS FIBRE REINFORCED CEMENT WALL OR FLOOR TILES

Abstract

A wireless system comprising a network of hose stations for receiving upiind signals transmitted from a plurality of remove terminal and for transmitting downlink singnal to said plurality of remote terminals using a plurality of conventional channels including a plurality of antenna elements each base station for receiving uplink signals, a plurality of antenna elements at each base station for transmitting downlink signals, a signal procesor at each lease station connected to the receving antenna elements and to the transmitting antenna elements for determind spalial signatures and multiplexing and lmultiplexing functions for each remote terminal antenna for each conventional channel and a multiple base station network controller for optimum network performance, whereby communication between said base stations and a plurality of remote terminals in each of the conventional channels can occur simultaneously. PRICE: THIRTY RUPEES

Full Text

This invention relates to a wireless system tor calculating uplink signals transmitted from a plurality of remote tenninals using a common uplink channel. Wireless communication systems can be used to complement and in some instances replace conventional wired communication systems in areas where conventional wire-line systems are unavailable, unreliable or excessively expensive. Examples of such areas are : rural areas with a small number of widespread users, underdeveloped areas with little or no current infrastructure, reliability sensitive applications in areas where wired infrastructure is unreliable and political environments where monopolistic wired service providers maintain artificially high prices. Even in metropolitan areas and highly developed countries, wireless communication systems may be used for low-cost ubiquitous communication, new flexible data services and emergency communication systems. In general, wireless communication systems may be used for voice communications just Hke conventional telephone systems, and for data communications in a radio-based wide area or local area network as well. Wireless users access wireless communication systems using remote tenninals such as cellular telephones and data modems equipped with radio transceivers. Such systems (and in particular the remote terminals) have protocols tor initiating calls, receiving calls and general transfer of information. The information transfer can be performed in real-time such as is the case for circuit-switched voice conversations and faxes, or in a store-and forward manner such as is often the case for electronic mail, paging and other similar message transfer systems. Wireless communication systems are generally allocated a portion of the radio frequency spectrum for their operation. The allocated portion of the spectrum is divided up into communication channels. These channels may be distinguished by frequency, by time, by code, or by some combination of the above. Each of these communication channels will be referred to herein as conventional channels. Depending on the available frequency allocations, the wireless system might have from one to several hundred communication channels. To provide fiill-duplex communication links, typically some of the communication channels are used for communication from base stations to users' remote terminals (the downlink) and others are used for communication from users' remote tenninals to base stations (the uphnk). Wireless communication systems generally have one or more radio base stations, each of which provide coverage to a geographic area known as a cell and often serve as a point-of-presence (PoP) providing connection to a wide area network such as a Public Switched Telephone Network (PSTN). Often a predetermined subset of the available communication channels is assigned to each radio base station in an attempt to minimize the amount of interference experienced by users of the system. Within its cell, a radio base station can communicate simultaneously with many remote terminals by using different conventional communication channels for each remote terminal can be updated infrequently. !•) general, however, changes in the RF propagation environment Accordingly the present invention provides a wireless system for calculating uplink signals transmitted irom a plurality' of remote terminals using a common uplink channel, said system including at least one base station, said system comprising : receiving means at said at least one base station including a pluralitv of antenna elements and receivers for producing measurements of combinations of said uplink signals from said plurality of remote terminals using said common uplink channel, receive spatial processing means for determining and storing receive spatial signatures for said plurality of remote terminals using said measurements, spatial demultiplexing means using said receive spatial signatures and said measurements to calculate said uplink signals: transmission means including a plurality of transmit antenna elements and transmitters for transmitting multiplexed downlink signals to said plurality of remote terminals using a common downlink chamiel, transmit spatial processing means for determining and storing transmit spatial signatures for said plurality of remote tenninals: and spatial multiplexing means using said transmit spatial signatures and downlink signals to produce said multiplexed downlmk signals. I'he invention and objects and features thereof will be more readily apparent from the following detailed description together with the accompanying drawings, in which : Figure 1 is a functional block diagram of a base station in accordance with tlie invention. Figure 2 is a functional block diagram of multichannel receivers in the base station. Figure 3 is a functional bloclc diagram of a spatial demultiplexer in the base station. Figure 4 is a functional block diagram of a spatial multiplexer for one remote terminal on a particular conventional channel. Figure 5 is a functional block diagram of a multichannel transmitter in the base station. Figure 6 is a functional block diagram of a spatial processor in the base station. Figure 7 is a functional block diagram of a remote terminal with a transponder switch Figure 8 is a functional block diagram of a remote terminal. Figure 9 is a schematic diagram of a network system comprised of three base stations and a multiple base station controller. Dcscnpiinn of In rent ion Figure 1 depicts ilic prcrcrn-d ctiibodirrioiit, ol' a l)a,s<. si.amoii l a b.use siatidii loritrollcr .ids an interface belweeii lirlse sial i ai any oxieriial connection via biise siation comiiinnicaiion link and serves ro roordiiiate the o operation of base station in iik preferrrd rmljodinient. controller is implemenied with conventional central unit associated memory programming.> I'ieure (i shows ;i more di'iailod block, diaj^rain of ^ipatlal processor l.'i. .S()atial proccsscir I,'! produces and niamtaiiis spatial signatures for each ri>rnotp ternntial for caclrcotiveutional fr channel, and to llie respective^ iiiod sienals m .s[)atiai inull.iplexcrs 2'.\ to prcxiiico s()al,ially tiiiilt.iploxtHl signals lo he iransniitted 10 for each of the ni transmit antennas lach of the .V,.r conventional channels. 1 he illustrnlivo I'lnbodinuMU shows a sysleni with multipK^ fro(]tiency multiple access or code division iiiiiltiplc access system, coriiinoii oscillators :V2 would he augmented to relay common time slot or coiniiion code signals rt^spcctively rrom spatial processor 1.!. via transmitter control data 31. to rniillicliannel transmitters 17(a m). In an alternair cmbcxlimeiu, llic r(-moii' ti'rniirial provi(l(\s cimiial data coininnmcation. Dcmoiiulatc^d r(»coivrfl voice signal (il, sfieaker (iO. microphonia .')S, and vnirc signal to h(> t ratisiiiitl(>d ol) arc rrplaci-d by di{;ital interfaces vvell-kiujvvn in the art that allow data lo be transmitted lo and From an (Wternal data processinc; device (for example, a conipiUer). the r(>mole Icrminal.s on ili.il clianiiel to deterrniiie that [\wy ran share the channel without mterferenre. In a system with rn receive and m transmit, antenna elements, up to tn remote leriiiiiials can share the same conventional channel. More generally, the number of point-lo-poinl full-duplex communication links that can occupy the same conventional channel at the same time is i^iven by the smaller of the number of receive and transmit elements. multioliannel receiver 16 given a siiiRle unit power narrow hand .signal being iransniured by that partirular remoip terminal, at t.lial particular frequency. When the base station controller 1 forwards a call initialization request for a particular remote terminal via link '27. a channel selector ^T) searches active remote terminal list 'M to tind a conventional communication channel that can accommodate the remote terminal. In the [(referred Also, in an alternate embodiment, in the case that no conventional channel can be lound to accotn-iiiodate the remote terminal, channel selector '^o calculates whether some rcarr.lnge.nent of the existing remote terminals among the conventional channels would allow the remote are the most accurate in the sense of least iiie;in-s(juared error. Ii: paniciilar, I hey must closely match the signals transmitted by the reriiote terminals given the measurements made at iii(> base station by the multiple antenna elements. Rquaiions (9) and (115) represent only one way to calculate spatial mnltiplexmu, and demultiplexinK weights. There are other similar strategies that demonstrate properties similar to t hose shown in equation (16) and described in the previous paragraph. Other well known techniques for calculating weight matrices where B' is the well known Moore-Penrose pseudo-inverse of the matrix B satistying Bli^ = / (I he id Mitity matrix) for full-ranl^, matrices B having more columns than rows. B^ B = / lor full-rank matrices B having more rows than columns. In alternate embodiments also described in copending application 08/234.747, ihe system can use this information to derive transmit spatial signatures! albeit in a less t;lficient manner than the embodiment shown in figure full transponder capabilities, or the In the embodiintMii illustrated herein, the spatial processor tor eaoti h.'ise station in tlu' rellular-liki' wireless cornniuiucation t;ystein operates independently to iiiaxinuze the number of ronuniinication cliannels in the immediate fi>ll. However, significant system capacity improvements can he r('alize(J if the st)atial processor from each base siatioii communicates with and coordinates its elforls with lli.- s[)aiial [iroce.ssors trom other nearby cells. .\ specific iMiibodirnent is shown in tigure it. A mulliptt base station controller ()6 acts as ihe interface between the wide area network 65 throvigh link 68 anci" base stations 1 (a.b.c) via base station communication links 2 (a.b.c). Kach base station is responsible for providing coverage to a number of remote terminals. In ine rinbo remotes attached to a particular i)a.se siaiioii are located. Tsers oijuippcd witli r Each spatial processor contained in base stations 1 (a.b.c) measures and stores the spatial signatures of the remote terminals in its cell and also of the remote i(>rminals in ad.iac(Mit r signals on the uplink conlrol cliannol may be processed in rea lime using the spatial processing described in copending patent a[)plicatiGn DT/SOfi.til)'). Tliis would allow multiple remote terminals to request a communication channel at the same tmie. WE CLAIM : A wireless system for calculating uplink signals transmitted from a plurality of remote terminals using a common uplink channel, said system including at least one base station (l\ said system comorising : receiving means at said at least one base station (1) including a plurality of antenna elements (19a-m) and receivers (15) for producing measurements of combinations of said uplink signals from said plurality of remote terminals using said common uplink channel receive spatial processing means (13) for determining and storing receive spatial signatures for said plurality of remote terminals using said measurements, spatial demultiplexing means (20) using said receive spatial signatures and said measurements to calculate said uplink signals; transmission means including a plurality of transmit antenna elements (18a-m) and transmitters (14) for transmitting downlink signals to said pluraUty of remote terminals using a common downlink channel; transmit spatial processing means (13) for determining and storing transmit spatial signatures for said plurality of remote terminals; and spatial multiplexing means (23) usmg said transmit spatial signatures and downlink signals to produce said multiplexed downlink signals. The wireless system as claimed in claim 1, wherein said receive spatial processing means (13) comprises: a spatial signature list (36) comprising a receive spatial signature for each remote terminal in said plurality of remote terminals and said common uplink channel, receive spatial signature determining means (3S) for spatial signatures, and a receive channel selector (35) utilizing said receive spatial signatures to determine whether said common uplink channel can be forther shared by an additional remote terminal. The wireless system as claimed in claim 2, wherein said receive spatial processing means (13) comprises: a receive spatial weight processor (37) for calculating spatial demultiplexing weights for said plurality of remote terminals, said spatial demultin1«vinff weights being utilized by said spatial demultiplexing means to calculate said uplink signals. The wireless system as claimed in claim 3, wherein said receive spatial weight processor determines said columns of matrix W„ as follows: where ()* denotes the complex conjugate noise covariance matrix of said receiving means, Pr is the diagonal matrix of transmit powers of the remote terminals in said plurality of remote terminals, and Abr \s & demultiplexing spatial signature matrix whose columns are said receive spatial signatures for said plurality of remote terminals and said common uplink channel. The wireless system as claimed in claim 1, wherein said common uplink channel is one of a plurality of unlink- chAnnek and wherein said receive spatial processing means (13) comprises: an active remote terminal list (34) comprising a list of remote terminals assigned to at least one channel of said plurality of uplink channels, a spatial signature list (36) comprising a receive spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality of uplink channels, receive spatial signature determining means (38) for determining said receive spatial sianatiirfts in ,«wid smti^l stgnaiure list, a receive channel selector (35) using said active remote terminal list (34) and said spatial signature list (36) to determine assignments of each remote terminal in said active remote terminal list (34) to at least one of the channels of said plurality of unlink channels, and a receive spatial weight processor (37) for calculating spatial demultiplexing weights for each of the terminals in said active, remote, terminal list and each channel of said plurality of uplink channels assigned to at least one of the terminals in said active remote terminal list, said spatial demultiplexing weights being utilized by said spatial demultiplexing means (20) to calculate said uplink signals. The wireless system as claimed in claim I, wherein said common uplink channel is one of a plurality of uplink channels, said at least one base station (1) is one of a plurality of base stations, said receive spatial processing means (13) is one of a plurality of receive spatial processing means, each base station in said plurality of base stations having a corresponding receive spatial processing means in said plurality of receive spatial processing means, each receive spatial processing means in said plurality of receive spatial processing means comprising: an active remote terminal list (34) comprising a list of remote terminals assigned to at least one channel of said pluraUty of uplink channels, a spatial signature hst (36) comprising a receive spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality of uplink channels, receive spatial signature determining means (38) for determining said receive spatial signatures in said spatial signature list (36), and a receive spatial weight processor (37) for calculating spatial demultiplexing weights for each of the terminals in said active remote terminal list (34) and each channel of said plurality of uplink channels assigned to at least one of the terminals in said active remote terminal list (34X said spatial demultiplexing weights being utilized by said spatiaJ demultiplexing means (20) to calculate said uplink signals, said system further comprising: joint channel selector means (35) for jointly determining assignments of each remote terminal in each said active remote terminal list (34) to at least one of the channels of said plurality of uplink channels and to at least one of base stations of said plurality of base stations, and communication means (66) for communicating the status of said assignments between each base-station in said plurality of base stations and said joint channel selector means. The wireless system as claimed in claim I, wherein said spatial demultiplexing means calculates spatial demultiplexing weights for said common uplink channel as the columns of a matrix R^« as follows: where ()' denotes the complex conjugate transpose of a matrix, Rn„ is the noise covariance matrix of said receiver means, Pr is the diagonal matrix of transmit powers of the remote terminals in said plurality of remote terminals. and Ahr is a demultiplexing spatial signature matrix whose columns are said receive spatial signatures for said plurality of remote terminals and said common uplink channel, said spatial demultiplexing means using said spatial demultiplexing weights to calculate said uplink signals. The wireless system as claimed in claim 1, wherein said S3'stem comprises a transponder co-located with each remote terminal of said plurality of remote terminals and wherein receive spatial processing means (13) determines said receive spatial signatures using signals transponded from at least one of the transponders. The wireless system as claimed in claim 1, wherein each remote terminal of said plurality of remote terminals has a transponder and said receive spatial processing means (13) determines said receive spatial signatures using signals transponded from at least one of the transponders. The wireless system as claimed in claim 1, wherein said receive spatial processing means (13) determines said receive spatial signatures using the known location and directivity of said antenna elements (19a-m), and estimates of the directions of arrival of said uplink signals from said plurality of remote terminals. The wireless system as claimed in claim 1, wherein said receive spatial processing means (13) determines said receive spatial signatures using the known location and directivity of said antenna elements and the known location of said plurality of remote tenninals. The wireless system as claimed in claim 1, wherein said uplink signals have predetermined modulation format parameters, and said receive spatial processing means (13) determines said receive spatial signatures using said predetermined modulation format parameters of said uplink signals from said plurality of remote terminals. The wireless system as claimed in claim 1, wherein said receiving means and said transmission means share common antenna elements using duplexers. The wireless system as claimed in claim 1, wherein said receiving means and said transmission means share common antenna elements using transmit/receive switches. The wireless system as claimed in claim 1, wherein said common uplink channel is one of a plurality of uplink channels, said common downlink channel is one of a plurality of downlink channels, and wherein said receive spatial processing means (13) and said transmit spatial processing means (13) comprise: an active remote terminal list (34) comprising a list of remote terminals assigned to at least one of the channels of said plurality of uplink channels and remote terminals assigned to at least one of the channels of said plurality of downlink channels, a spatial signature list (36) comprising a receive spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality of uplink channels, and a transmit spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality' of downlink channels, receive spatial signature determining means (38) Ibr determining said receive spatial signatures, transmit spatial signature determining means (38) for determining said transmit spatial signatures, and a channel selector (35) using said active remote terminal list (34) and said spatial signature list to detemiine assignments of each remote terminal in said active remote terminal list (34) to at least one of the channels of said pluraUty of uplink channels and at least one of the channels of said plurality of downlink channels. 16. The wireless system as claimed in claim 15. wherein said receive spatial processing means (13) and said transmit spatial processing means (13) further comprise: a receive spatial weight processor (37) for calculating spatial demultiplexing v^eights for each of the terminals in said active remote termmals list to which a uplink channel is assigned and for each channel of said pluraliy of uplink channels assigned to at least one of the termmals m said active remote tenninal list, said spatial demultiplexing weights being utilized by said spatial demultiplexing means to calculate said uplink signals, and a transmit spatial weight processor (37) for calculating spatial multiplexing weights for each of the terminals in said active remote terminal list to which a downlink channel is assigned and each chamicl of said pluralit>' of downlink channels assigned to at least one of the terminals in said active remote terminal list, said spatial multiplexhig weights being utilized by said spatial multiplexing means to produce said multiplexed downlink signals. 17. The wireless system as claimed in claim I, wherein said at least one base slalion (1) is one of a plurality' of base stations, said common uplink channel is one of a plurality' of uplink channels, said common downlink channel is one of a plurality' of downlink channels, said receive spatial processing means (13) is one of a plurality' of receive spatial processing means, said transnih spatial processing means (13) is one of a plurality of transmit spatial processing means, each base station in said plurality of base stations having a corresponding receive spatial processing means in said plurality' of receive spatial processing means and a corresponding transmit spatial processing means in said plurality of transmit spatial processing means, each receive spatial processing means in said plurality of leceive spatial processing means and each transmit spatial processing means in said plurality of transmit spatial processing means comprising: an active remote terminal list (34) comprising a list of remote terminals assigned to at least one of the channels of said plurality of uplink channels and remote terminals assigned to at least one of the channels of said plurality- of downlink channels, a spatial signature list (36) comprising a receive spatial signature tor each remote terminal of said plurality' of remote terminals and each channel of said plurality of uplink channels, and a transmit spatial signature tor each remote tenninal of said plurality of remote terminals and each channel of said plurality of downlink channels, receive spatial signature determining means (38) for determining said receive spatial signatures, transmit spatial signature determining means (38) tor determining said transmit spatial signatures, a receive spatial weight processor (37) for calculating spatial demultiplexing weights for each of the terminals in said active remote terminal list to which a uplink channel is assigned and each channel of said plurality of uplink channels assigned Lo at least one of the terminals in said active remote terminal list, said spatial demultiplexing weights being utilized by said spatial demultiplexing means to calculate said uplink signals, and a transmit spatial weight processor (37) tbr calculating spatial multiplexing weights for each of the terminals in said active remote terminal list to which a downlink channel is assigned and each channel of said plurality of downlink channels assigned to at least one of the terminals in said active remote terminal list, said spatial multiplexing weights being utilized by said spatial multiplexing means to produce said multiplexed downhnk signals, said system further comprising: joint channel selector means (35) for jointly determining assignments of each remote terminal in each said active remote terminal list to at least one of the channels of said plurality of uplink channels, to at least one of the channels of said plurality of downlink channels and to at least one of the base stations of said plurality of base stations, and communication means (66) for communicating said assignments between each base station in said plurality of base stations and said joint channel selector means. The wireless system as claimed in claim 1, wherein said spatial multiplexing means determines spatial multiplexing weights for said common dovv/nhnk channel as the rows of a matrix Wt^ as follows: W,=:S,(A,,A:,)-'A,, where () denotes the complex conjugate transpose of a matrix. Si, is the diagonal matrix of amplitudes of said downlink signals, and Arh is a signatures for said plurality of remote terminals and said common downlink channel, and wherein said spatial multiplexing means utilizes said spatial multiplexing weights to produce said multiplexed downlink, signals. The wireless system as claimed in claim I, wherein said system comprises a transponder co-located with each remote terminal of said pluralit}' of remote terminals and wherein transmit spatial processing means (13) determines said transmit spatial signatures using signals transponded from at least one of the transponders. The wireless system as claimed in claim 1, wherein each remote terminal in said plurality of remote terminals has a transponder, and wherein said transmit spatial processing means (13) determines said transmit spatial signatures using signals transponded from at least one of the transponders. The wireless system as claimed in claim 1, wherein said downlink signals have predetermined modulation format parameters, and said transmit spatial signatures are determined by the corresponding terminals in said plurality of remote terminals using the predetermined modulation tbnnat parameters of said downlink signals. The wireless system as claimed in claim 1, wherein said transmit spatial processing means (13) determines said transmit spatial signatures using the known location and directivity of said transmit antenna elements and estimates of directions of arrival of said uplink signals from said plurality of remote tenninals. 23. The wireless system as claimed in claim 1, wherein said downlink signals and said uplink signals are transmitted on the same radio frequency and said transmit spatial processing means (13) determines said transmit spatial signatures by calculating them directly from said receive spatial signatures. 24. The wireless system as claimed in claim I, wherein said transmit spatial processing means (13) determines said transmit spatial signatures using the known location and directivity of said antenna elements (18a-m) and the known location of said plurality of remote tenninals. 25. A wireless system for calculating uplink signals transmitted from a plurality of remote terminals using a common uplink channel substantially as herein described with reference to the accompanying drawings.

Documents:

1568-mas-95 abstract.pdf

1568-mas-95 claims.pdf

1568-mas-95 correspondence-others.pdf

1568-mas-95 correspondence-po.pdf

1568-mas-95 description(complete).pdf

1568-mas-95 form-1.pdf

1568-mas-95 form-4.pdf