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WO1998043363A1 - Procede pour regenerer des signaux lmds et noeud pour ledit procede - Google Patents

Procede pour regenerer des signaux lmds et noeud pour ledit procede Download PDF

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Publication number
WO1998043363A1
WO1998043363A1 PCT/US1997/004730 US9704730W WO9843363A1 WO 1998043363 A1 WO1998043363 A1 WO 1998043363A1 US 9704730 W US9704730 W US 9704730W WO 9843363 A1 WO9843363 A1 WO 9843363A1
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WO
WIPO (PCT)
Prior art keywords
lmds
regenerating
antenna
node
cell site
Prior art date
Application number
PCT/US1997/004730
Other languages
English (en)
Inventor
Ronald D. Mccallister
Robert J. Solem
Original Assignee
Sicom, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sicom, Inc. filed Critical Sicom, Inc.
Priority to AU25878/97A priority Critical patent/AU2587897A/en
Publication of WO1998043363A1 publication Critical patent/WO1998043363A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/26—Cell enhancers or enhancement, e.g. for tunnels, building shadow
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2603—Arrangements for wireless physical layer control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/32—Hierarchical cell structures
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/08—Access point devices
    • H04W88/085—Access point devices with remote components

Definitions

  • the present invention relates to cellular communication systems. More specifically, the present invention relates to the regenerating of local multipoint distribution system (LMDS) signals.
  • LMDS local multipoint distribution system
  • FIG. 1 illustrates an exemplary conventional macro voice cellular arrangement of base stations (BS) 10 with corresponding cells 11.
  • BS base stations
  • FIG. 1 illustrates a seven cell frequency reuse plan in which a macro cell I T is assigned a frequency set "A" and adjacent macro cells 11 are assigned frequency sets "B-G.”
  • macro cells 11 are around 2-10 miles in diameter.
  • FIG. 2 illustrates an exemplary micro cellular system in which the macro cell 11' from FIG. 1 is replaced by seven smaller micro cells 12.
  • a seven cell frequency reuse plan allocates the entire cellular frequency spectrum to the same geographic area (i.e.
  • Each micro cell 12 has its own micro base station (MBS) 13.
  • MBS micro base station
  • Conventional micro cellular base stations 13 are complex and expensive items of equipment.
  • Each micro base station 13 may handle the same volume of communication as its macro base station 10 counterpart (see FIG. 1) and may likewise couple to the PSTN and perform switching and handoff functions.
  • legal and political solutions must be found to the problems of acquiring physical facilities at which to locate each micro base station 13, at which to connect to the PSTN, and at which to erect antenna towers. Accordingly, the increased infrastructure costs of establishing numerous micro base stations 13 is prohibitive in all but areas of intense population density.
  • LMDSs Local multipoint distribution systems
  • LMDS Local multipoint distribution systems
  • LMDS are RF cellular digital data communication systems which augment or replace wired land-line telecommunications available to stationary subscribers.
  • an LMDS operates in or near the K. band where a wide portion of the electromagnetic spectrum may be dedicated for exclusive use by the LMDS. This wide bandwidth allows LMDS subscribers to communicate data at much higher data rates than may be currently accommodated through wired land-line connections.
  • An LMDS need not entirely replace the public switched telecommunications network (PSTN). Rather, an LMDS may couple to a PSTN and use the PSTN to trunk bulk communications.
  • PSTN public switched telecommunications network
  • an LMDS replaces or augments the final wiring links between a central office and subscribers' premises much like conventional cellular communication systems use RF communications as a final link to cellular radiotelephone subscriber units.
  • LMDS communication faces an implementation problem similar to the micro cellular system implementation problem. Referring to FIG. 3, the high frequencies at which LMDS communications take place do not penetrate objects, such as a building 14. Thus, within an LMDS cell, equipment located inside the building 14 or in a shadow area 15 behind the building 14 may not be able to communicate with an LMDS base station 16. In addition, the short wavelengths at these frequencies produce an environment of increasingly intense diffuse reflections from the ground and other surfaces as distances from the LMDS base station 16 increase.
  • Another advantage of the present invention is that voice cellular signals are regenerated and merged with LMDS communication traffic.
  • an LMDS signal regenerating node serves as a micro cellular system base station.
  • Another advantage is that LMDS communication is extended over a macro voice cellular communication cell using existing physical voice cellular facilities.
  • Another advantage is that LMDS communication is extended over a macro cell without encountering the substantial legal and political obstacles normally encountered when erecting tall antennas in urban areas. Another advantage is that a method and node are provided for repeating voice cellular and/or LMDS signals without significantly degrading signal quality.
  • Another advantage is that a method and node are provided which efficiently trunk voice cellular communications to a macro base station using a portion of an allocated LMDS frequency spectrum.
  • the above and other advantages of the present invention are carried out in one form by a method of regenerating local multipoint distribution system (LMDS) cell site communication signals.
  • the method calls for receiving a multi-channel RF communication spectrum at a regenerating node.
  • the regenerating node determines the LMDS traffic capacity required to convey the communication signals to the LMDS cell site. This capacity is requested from the cell site, and the communication signals are transmitted to the cell site utilizing the requested capacity.
  • FIG. 1 shows a block diagram of a macro voice cellular communication system
  • FIG. 2 shows a block diagram of a micro voice cellular communication system
  • FIG. 3 shows a block diagram of an LMDS communication system
  • FIG. 4 shows a block diagram of an LMDS communication system which includes regenerating nodes
  • FIG. 5 shows a chart of portions of the electromagnetic spectrum which may be allocated to voice cellular communications and to LMDS communications;
  • FIG. 6 shows a block diagram of the regenerating node
  • FIG. 7 shows a flow chart of a receive voice cellular process carried out by the regenerating node
  • FIG. 8 shows an exemplary spectral diagram of a voice cellular spectrum
  • FIG. 9 shows a format diagram of an exemplary LMDS communication frame
  • FIG. 10 shows a flow chart of a receive downstream LMDS traffic process carried out by the regenerating node
  • FIG. 11 shows a flow chart of a receive upstream LMDS traffic process carried out by the regenerating node.
  • FIG. 4 shows a block diagram of a cellular LMDS communication system 20.
  • System 20 includes an LMDS cell site 22, any number of regenerating nodes 24, any number of LMDS subscriber units 26, and any number of voice cellular subscriber units 28.
  • LMDS cell site 22 includes an LMDS base station 30 which couples to a voice cellular base station 32 and the public switched telecommunication network (PSTN) 34.
  • PSTN public switched telecommunication network
  • Voice cellular base station 32 likewise couples to PSTN 34.
  • LMDS cell site 22 communicates with regenerating nodes 24 and/or LMDS subscriber units 26 using an LMDS spectrum.
  • Regenerating nodes 24 communicate with other regenerating nodes 24 and/or with LMDS subscriber units 26 using the LMDS spectrum.
  • regenerating nodes 24 communicate with mobile or portable communication equipment which use a much lower frequency portion of the RF spectrum.
  • regenerating nodes 24 may communicate with voice cellular subscriber units 28 using a voice cellular spectrum, but those skilled in the art will appreciate that nodes 24 may also communicate with other RF communication devices.
  • FIG. 5 shows a chart of portions of the electromagnetic spectrum which may be allocated to a micro cell multi-channel, voice cellular RF spectrum 36 and to an LMDS spectrum 38.
  • voice cellular spectrum 36 has substantially no frequency in common with LMDS spectrum 38 so that substantially no interference occurs between simultaneous communications taking place using spectrums 36 and 38.
  • Voice cellular spectrum 36 or the spectrum occupied by other RF communication devices such as personal communication system (PCS) devices, typically occupies lower frequencies at which signals propagate through and around many obstacles. Desirably, spectrum 36 is confined to being less than 2 GHz.
  • voice cellular spectrum 36 is suited for mobile and portable applications where voice cellular subscriber units 28 (see FIG. 1) may freely move about.
  • voice cellular spectrum 36 has a much narrower bandwidth than LMDS spectrum 38.
  • An entire spectrum allocated to a micro cell for which a regenerating node 24 serves as a micro base station may span less than 20 MHz.
  • over 2 GHz of bandwidth may be allocated to LMDS spectrum 38, which is desirably positioned above 20 GHz.
  • LMDS spectrum 38 By positioning LMDS spectrum 38 above 20 GHz, small, practical, low cost narrow beam antennas may be used. While FIG. 5 illustrates specific frequencies and bandwidths, those skilled in the art will appreciate that the present invention is certainly not limited to the precise depicted values.
  • voice cellular base station 32 is provided by a substantially conventional cellular base station 10 or 13 (see FIGs. 1-2), except that RF communication components may be omitted.
  • cellular base station 32 is configured to handle subscriber registration, call setup, call tear down, call handoff, and a mobile telephone switching office (MTSO) interface through PSTN 34.
  • MTSO mobile telephone switching office
  • LMDS base station 30 may be provided by a conventional LMDS base station 16 (see FIG. 3) except that data streams are multiplexed between PSTN 34 and voice cellular base station 32 rather than simply interfaced to PSTN 34.
  • digitized voice cellular communication channels are routed to voice cellular base station 32 while other LMDS data traffic is routed to PSTN 34.
  • Cellular base station 32 processes the digitized voice cellular communication channels in a conventional manner.
  • an LMDS cell site 22 is located in an existing macro cellular facility established for a macro base station 10 (see FIG. 1). This location gives LMDS cell site 22 physical facilities in which to locate equipment, access to PSTN 34 and the public power grid (not shown). In addition, this location gives LMDS cell site 22 an existing tower upon which to mount one or more LMDS antennas 40.
  • LMDS antenna 40 may be mounted at approximately the height of existing voice cellular communication antennas (not shown) or perhaps a few feet higher. This placement typically causes antenna 40 to reside slightly above surrounding terrain and obstacles. In many situations, this placement will not achieve sufficient elevation to guarantee good radio coverage throughout a macro cell 11 (see FIG. 1). However, coverage is sufficient to reach an assortment of strategically placed regeneration nodes 24 distributed throughout the macro cell 11. Moreover, problems associated with legal and political ramifications of obtaining physical facilities and antenna towers for an LMDS system are reduced by using existing facilities and antenna towers.
  • LMDS antenna 40 is desirably a wide beam, directional antenna which is angled slightly downward and away from its tower at cell site 22. Antenna 40 may produce an antenna pattern for up to a 360 azimuth. In addition, antenna 40 is compatible with frequencies in LMDS spectrum 38 (see FIG. 5). As discussed above, at these frequencies communication signals follow a substantially line-of-sight propagation path which may be blocked by obstacles and which readily produces diffuse reflections.
  • Each regenerating node 24 includes a narrow beam, directional antenna 42 and a wide beam, directional antenna 44, each of which are compatible with frequencies in LMDS spectrum 38.
  • Narrow beam antenna 42 is desirably constructed using conventional low cost circuit board antenna techniques to achieve a beam width of around 1-2°.
  • Regenerating node 24 and antenna 42 are desirably mounted in a line of sight with cell site antenna 40.
  • regenerating node 24 and its antennas are mounted on roof tops, utility poles, or the like at a height typically above nearby obstacles but lower than the height of cell site antenna 40.
  • Regenerating nodes 24 need not have access to PSTN 34, but access to the public power grid is desirable.
  • the lowered height of antennas 42 and 44 relative to antenna 40 permits regenerating nodes 24 to forgo many of the legal, political, and zoning problems which often accompany the erection of antenna towers.
  • Narrow beam antenna 42 is desirably aimed toward LMDS cell site antenna 40 by being angled relatively upward.
  • the use of narrow beam antenna 42 reduces multipath and interference with other nearby communications simultaneously taking place in LMDS spectrum 38.
  • Such nearby communications include communications taking place through wide beam antenna 44.
  • wide beam antenna 44 may have a beam azimuth of up to 360° but a limited elevation angle.
  • Antenna 44 is aimed downward relative to the aiming direction of narrow beam antenna 42.
  • an isolating member 46 such as a suitable conductive plate, is desirably positioned between antennas 42 and 44 to further isolate the antennas from one another and lessen the likelihood of interference.
  • Regenerating node 24 also includes a wide beam voice cellular antenna 48. Through antenna 48, regenerating node 24 communicates with nearby voice cellular subscriber units 28 using voice cellular spectrum 36 (see FIG. 5). Desirably, frequency allocations and power levels are adjusted to restrict such communications to a micro cell, such as micro cells 12 (see FIG. 2). As discussed above, voice cellular spectrum 36 desirably exhibits a sufficiently low frequency so that signals go through and around obstacles. Consequently, voice cellular subscriber units 28 may be configured as battery-powered mobile or portable units.
  • FIG. 4 illustrates a tiered arrangement of LMDS nodes.
  • LMDS base station 30 resides at the highest level of the arrangement, both logically and in elevation.
  • regenerating node 24' resides at the next lower tier, while LMDS subscriber unit 26 and regenerating node 24" reside at an even lower tier.
  • LMDS subscriber units 26 and regenerating node 24" may communicate directly with LMDS base station 30, in the FIG. 4 example they communicate indirectly through regenerating node 24'. Indirect communication through regenerating node 24' may be desirable when a distance from cell site 22 or obstacles prevent direct communication.
  • each regenerating node 24 is configured to regenerate signals being communicated between LMDS base station 30 and tiers beneath the regenerating node 24.
  • a narrow beam antenna 42 of LMDS subscriber unit 26 aims at wide beam antenna 44 of regenerating node 24', and a narrow beam antenna 42 of regenerating node 24" aims at wide beam antenna 44 of regenerating node 24'.
  • regenerating nodes 24' and 24" may be identical to one another.
  • LMDS subscriber unit 26 does not perform LMDS signal regenerating.
  • a LMDS subscriber unit 26 may be co-located with a regenerating node 24 from a higher tier and communication therebetween conducted internally rather than through an LMDS communication link.
  • FIG. 6 shows a block diagram of a regenerating node 24.
  • the block diagram of FIG. 6 is best understood when viewed in conjunction with FIGs. 7, 10, and 11.
  • FIG. 7 shows a flow chart of a receive voice cellular process 50 carried out by regenerating node 24.
  • FIG. 10 shows a flow chart of a receive downstream LMDS traffic process 52 carried out by regenerating node 24, and
  • FIG. 11 shows a flow chart of a receive upstream LMDS traffic process 54 carried out by regenerating node 24.
  • voice cellular antenna 48 couples to a multi-channel RF communication receiver.
  • antenna 48 couples to an input of an RF amplifier 56, and an output of RF amplifier 56 couples to a first input of a mixer 58.
  • a suitable oscillation signal is provided to a second input of mixer 58 so that mixer 58 generates a broadband downconverted signal.
  • An output of mixer 58 couples to an input of a digitizer 60, and an output of digitizer 60 couples to an input of a transmultiplexer, or transmultiplexer filter, 62.
  • Outputs of filter 62 couple to input ports of a switch fabric 64, and output ports of switch fabric 64 couple to input ports of a switch fabric 66.
  • An output port of switch fabric 66 couples to a modulator (MOD) 68, and an output of modulator 68 generates a modulation signal and couples to a first input of a mixer 70.
  • a suitable oscillation signal is provided to a second input of mixer 70 to upconvert the modulated signal to an LMDS frequency signal, and the LMDS frequency signal is transmitted at antenna 42 after amplification in an amplifier 72.
  • a controller 74 controls digitizer 60, transmultiplexer filter 62, switch fabrics 64 and 66, and modulator 68 (not shown). Controller 74 represents a programmable device which operates as instructed via computer software.
  • Switch fabrics 64 and 66 may be provided using conventional space or time switching techniques. In one embodiment, transmultiplexer filter 62 and switch fabrics 64 and 66 are implemented substantially within controller 74 through appropriate computer software.
  • receive voice cellular process 50 performs a task 76.
  • regenerating node 24 receives the multi-channel voice cellular spectrum 36 (see FIG. 5) at antenna 48.
  • the voice cellular spectrum is downconverted to baseband. If for example, voice cellular spectrum 36 is a 20 MHz spectrum, task 78 generates a 20 MHz broadband downconverted signal which has characteristics proportional to the relative spectral energy received in task 76.
  • FIG. 8 shows an exemplary spectral diagram of multi-channel voice cellular spectrum 36. As illustrated in FIG. 8, at any given instant, spectrum 36 may include active channels 80 and inactive channels 82.
  • Active channels 80 may be distinguished from inactive channels 82 because frequencies associated with active channels 80 exhibit significantly higher energy levels than frequencies associated with inactive channels 82. Thus, the energy level exhibited at one channel may be different relative to the energy levels exhibited at other channels.
  • the broadband downconverted signal has characteristics proportional to the varying spectral energy levels throughout spectrum 36.
  • a task 84 performed using digitizer 60, digitizes the entire spectrum 36 to generate a digitized signal.
  • task 82 is performed regardless of whether voice cellular spectrum 36 conveys analog or digital communications. Rather, task 84 digitizes whatever energy is present throughout the entire spectrum 36.
  • a task 86 analyzes the digitized signal using transmultiplexer filter 62. Task 86 utilizes conventional transmultiplexer techniques to simultaneously filter spectrum 36 into numerous frequency bins which correspond to channels 80 and 82.
  • a task 88 is performed using transmultiplexer filter 62, switch fabric 64 and/or controller 74 to evaluate the amounts of energy present in the various channels 80 and 82. From this evaluation, task 88 identifies active channels 80 and inactive channels 82.
  • a task 90 switches active channels 80 through switch fabrics 64 and 66 into upstream LMDS communications traffic.
  • Task 90 simultaneously blocks the merging of inactive channels 82 into upstream LMDS communication traffic.
  • upstream LMDS communications traffic refers to LMDS communications taking place between regenerating node 24 and a higher tier of system 20, such as LMDS cell site 22, and downstream LMDS traffic refers to LMDS communications taking place between a regenerating node 24 and a lower tier of system 20 (see FIG. 4).
  • FIG. 9 shows a format diagram of an exemplary LMDS communication frame 92.
  • Frame 92 may be divided into various blocks 94 of time which are allocated to various users.
  • FIG. 9 illustrates blocks 94 as being sequentially arranged within frame 92.
  • blocks 94 may actually be interleaved with one another throughout frame 92.
  • Each block 94 may include any number of discrete time slots (not shown) and the quantity of each block's time slots (i.e. allocated capacity) may change from time to time as system 20 operates.
  • One block 96 of frame 92 is allocated to voice cellular communications. Referring to FIG. 7, task 90 operates switch fabrics 64 and 66 so that digitized active voice communication channels 80 are applied to modulator 68 during block 96 of each frame 92.
  • a task 98 modulates, upconverts, and transmits the active voice communication channels as LMDS traffic.
  • Task 98 uses modulator 68, mixer 70, and narrow beam antenna 42. Only the capacity allocated to voice cellular communications of LMDS frames 92 is used by task 98.
  • the transmitted signal is received at LMDS base station 30 (see FIG. 4).
  • LMDS base station 30 extracts the digital data which correspond to active channels 80 and routes these data to voice cellular base station 32 (see FIG. 4).
  • Voice cellular base station 32 processes the data in a conventional manner as if voice communication signals were directly received at cell site 22.
  • regenerating node 24 aids the implementation of a micro cellular communication system by serving in the role of a micro cellular base station.
  • regenerating node 24 separates active channels 80 from inactive channels 82 and digitally communicates active channel energy back to voice cellular base station 32 for processing.
  • the omission of further processing at regenerating node 24 allows equipment complexity and costs to remain low so that many regenerating nodes 24 may be installed within a given area at relatively low cost.
  • a task 100 gets a current voice cellular capacity allocation for the
  • task 100 determines the amount of time allocated to voice block 96 in each LMDS frame 92.
  • Task 100 and tasks following task 100 are performed substantially using controller 74.
  • a query task 102 determines whether this capacity allocation is adequate for current active channel needs.
  • Task 102 desirably tests for both over-allocated and under-allocated situations. Over allocation occurs when more calls have terminated than have been setup, and excessive LMDS capacity is going unused. Under allocation occurs when a greater number of calls have been setup than have terminated.
  • regenerating node 24 reserves a small amount of unused LMDS capacity so that any newly appearing energy in voice cellular spectrum 36 may be quickly conveyed to voice cellular base station 32. If this reserve gets too low, then task 102 may determine that allocation is inadequate.
  • Task 102 may compare the number of currently active channels 80 to the current size of voice block 96.
  • a task 104 requests an LMDS capacity allocation change by transmitting an appropriate message to LMDS base station 30 (see FIG. 4) using a control block 106 of LMDS frame 92.
  • program flow exits process 50.
  • process 50 is an ongoing process and that process 50 continuously repeats for different instants in time. Due to the transmission of active channels 80 and the requesting of an adequate capacity allocation in LMDS frame 92, process 50 uses LMDS spectrum 38 efficiently. Due to process 50 requesting LMDS capacity in excess of current LMDS traffic capacity requirements, voice cellular communication signals are nevertheless quickly communicated to voice cellular base station 32.
  • downstream LMDS traffic is received at wide beam antenna 44.
  • Antenna 44 couples to an input of an RF amplifier 108, and an output of RF amplifier 108 couples to a first input of a mixer 110.
  • a suitable oscillation signal is provided to a second input of mixer 110 so that mixer 110 generates a baseband LMDS signal.
  • An output of mixer 110 couples to an input of a demodulator (DEMOD) 112, and an output of demodulator 112 couples to an input port of switch fabric 66.
  • DEMOD demodulator
  • received downstream LMDS traffic may be directly routed to switch fabric 66 from LMDS subscriber unit 26, bypassing RF components 108, 110, and 112.
  • Task 114 is performed primarily by controller 74.
  • Task 114 identifies the occurrence of control channel 106 in LMDS frame 92 and of any block 94 allocated to nodes in system 20 that are positioned beneath regenerating node 24 in the tiered arrangement of system 20.
  • a block 116 in LMDS frame 92 may be allocated to LMDS subscriber unit 26 (see FIG. 4) and a block 118 may be allocated to regenerating node (RN) 24" (see FIG. 4).
  • RN regenerating node
  • a task 120 downconverts and demodulates the received LMDS signal using mixer 110 and demodulator 112 to extract the data being conveyed.
  • a task 122 switches the extracted data into upstream LMDS traffic flow through switch fabric 66.
  • Modulator 68, mixer 70, and antenna 42 modulate the data, upconvert the modulated data to LMDS frequencies, and transmit the LMDS signals during a task 124.
  • Task 124 uses only the capacity within LMDS frames 92 that is allocated to downstream LMDS traffic through this regenerating node 24.
  • program flow exits process 52. However, those skilled in the art will appreciate that process 52 is an ongoing process and that process 52 continuously repeats for different instants in time.
  • the LMDS signals transmitted during task 124 are received at LMDS base station 30 (see FIG. 4). LMDS base station 30 demodulates these signals and extracts the data therefrom. These data may then be routed toward their destinations via PSTN 34.
  • upstream LMDS traffic is received at narrow beam antenna 42.
  • Antenna 42 couples to an input of an RF amplifier 126, and an output of RF amplifier 126 couples to a first input of a mixer 128.
  • a suitable oscillation signal is provided to a second input of mixer 128 so that mixer 128 generates a baseband LMDS signal.
  • An output of mixer 128 couples to an input of a demodulator (DEMOD) 130, and an output of demodulator 130 couples to an input port of a switch fabric 132.
  • One output port of switch fabric 132 couples to an input of a digital communication modulator 134.
  • An output of modulator 134 couples to a first input of a mixer 136, and a suitable oscillation signal is applied to a second input of mixer 136.
  • An output of mixer 136 couples through amplifier 138 to wide band LMDS antenna 44.
  • Switch fabric 132 couples to inputs of a switch fabric 140.
  • Output ports of switch fabric 140 couple to a combining circuit 142.
  • An output of combining circuit 142 couples to an optional digital to analog converter (DIA) 144.
  • An output of D/A 144 couples to an input of a modulator 146.
  • An output of modulator 146 couples to a first input of a mixer 148, and a suitable oscillation signal is applied to a second input of mixer 148.
  • An output of mixer 148 couples through amplifier 150 to voice cellular antenna 48.
  • Controller 74 couples to and controls switch fabrics 132 and 140.
  • Switch fabrics 132 and 140 may be provided using conventional space or time switching techniques. In one embodiment, switch fabrics 132 and 140 and combining circuit 142 are implemented substantially within controller 74 through appropriate computer software.
  • receive upstream LMDS traffic process 54 performs a task 152.
  • Task 152 is performed using antenna 42, amplifier 126, mixer 128, and demodulator 130 to downconvert and demodulate the LMDS signal received from upstream, or higher tier, LMDS nodes of system 20. While nothing requires received upstream LMDS signals to follow precisely the same block allocations used at any given instant for transmitted upstream LMDS signals, such received upstream LMDS signals may nevertheless adopt the same block allocation system set forth by frame 92.
  • a query task 154 determines whether received upstream LMDS data correspond to control block 106. If control block 106 is identified, a task 156 responds to any commands directed to this regenerating node 24.
  • Such commands may instruct regenerating node 24 to alter capacity allocations defined by blocks 94.
  • the alteration may take the form of increasing or decreasing block 94 durations, terminating no longer used blocks 94, or creating new blocks 94.
  • control block 106 may be regenerated by being transmitted on to lower tier nodes.
  • a query task 158 determines whether received upstream LMDS data correspond to lower tier LMDS data traffic.
  • the lower tier traffic may be identified by block 94 allocations in frame 92. For the example depicted in FIG. 4, blocks 116 and 118 are allocated to data intended for LMDS subscriber unit 26 and regenerating node 24", respectively.
  • a task 160 switches the data through switch fabric 132 to modulator 134 to appropriately incorporate the data into downstream LMDS traffic flow.
  • modulator 134, mixer 136, amplifier 138, and antenna 44 modulate, upconvert, and transmit the LMDS data so that it may be received by lower tier nodes.
  • a query task 164 determines whether received upstream LMDS data correspond to voice cellular data.
  • Voice cellular data may be identified by detecting the occurrence of block 96 in frame 92.
  • a task 166 switches the discrete voice calls into active channels 80 (see FIG. 8) through switch fabrics 132 and 140.
  • a task 168 combines active voice channels 80 with simulated inactive channels 82 to regenerate the entire voice cellular spectrum 36 (see FIG. 8).
  • an optional task 170 converts the combined signal into an analog signal using D/A 144.
  • Task 170 may be omitted when a digital voice cellular system is being implemented.
  • modulator 146, mixer 148, amplifier 150, and antenna 48 modulate, upconvert, and transmit the voice cellular RF communication signal so that it may be received by voice cellular subscriber units 28 (see FIG. 4).
  • program flow exits process 54 with respect to the just-processed data.
  • program flow exits process 54 with respect to the just processed data.
  • data may represent an unused block of LMDS capacity within frame 92 or a block that is processed by an equivalent or higher tier regenerating node 24 or LMDS subscriber unit 26.
  • the present invention provides an improved LMDS signal regenerating method and node.
  • the LMDS regenerating node serves as a micro voice cellular base station.
  • Lower frequency voice cellular or other signals are regenerated and merged with higher frequency LMDS communication traffic.
  • a system employing the regenerating nodes with an LMDS base station extends LMDS communication over a macro cellular communication cell using existing macro voice cellular facilities. The use of existing facilities avoids the substantial legal and political obstacles normally encountered when erecting tall antennas in urban areas because suitable antenna towers are already in place.
  • the regenerating node employs digital communication techniques. Rather than merely amplifying and repeating weak signals, the regenerating node extracts data and re-modulates using digital communication techniques which minimize signal degradation.
  • Voice cellular data is sampled from the voice cellular spectrum assigned to a micro cellular base station/regenerating node without regard to modulation techniques used by the voice cellular system.
  • Active voice cellular channels are extracted from the cellular spectrum and trunked to a macro voice cellular base station using an allocated portion of the total capacity of an LMDS frequency spectrum.
  • the present invention has been described above with reference to preferred embodiments. However, those skilled in the art will recognize that changes and modifications may be made in these preferred embodiments without departing from the scope of the present invention.
  • the present invention is not limited to regenerating a voice cellular spectrum but may alternatively regenerate a PCS spectrum or other lower frequency RF communication system spectrum.
  • processes performed at the regenerating node may classify and sequence tasks differently than discussed herein while achieving equivalent results.

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Abstract

Un système de communication (20) met en place à la fois un système de communication vocal micro-cellulaire et un système de communication de type distribution multipoint locale (LMDS) à l'intérieur d'une cellule (11) d'un système vocal macro-cellulaire en utilisant les installations vocales macro-cellulaires existantes et un certain nombre de noeuds de régénération (24). Un noeud de régénération (24) comprend une antenne LMDS à faisceau étroit (42) et une antenne LMDS à faisceau large (44). L'antenne à faisceau étroit (42) est dirigée vers les antennes à faisceau large (40, 44) des noeuds LMDS des étages supérieurs. Le noeud de régénération (24), qui comprend également une antenne de type vocal (48) de la cellule, convertit la totalité du spectre vocal (36) de la cellule en bande de base (78) et le numérise (84). Les canaux vocaux cellulaires actifs (80) sont ensuite identifiés (88) et fusionnés (98) avec le trafic de données LMDS d'aval reçues, de façon à former un trafic de données LMDS d'amont.
PCT/US1997/004730 1996-02-09 1997-03-24 Procede pour regenerer des signaux lmds et noeud pour ledit procede WO1998043363A1 (fr)

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Application Number Priority Date Filing Date Title
AU25878/97A AU2587897A (en) 1997-03-24 1997-03-24 Lmds signal regenerating method and node therefor

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Application Number Priority Date Filing Date Title
US59889396A 1996-02-09 1996-02-09

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WO1998043363A1 true WO1998043363A1 (fr) 1998-10-01

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PCT/US1997/004730 WO1998043363A1 (fr) 1996-02-09 1997-03-24 Procede pour regenerer des signaux lmds et noeud pour ledit procede

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0962107A4 (fr) * 1997-01-17 2001-12-19 Univ California Systeme de telecommunications large bande, universel, hybride utilisant de petites cellules radio interconnectees par des liaisons optiques dans l'espace libre
FR2820257A1 (fr) * 2001-01-26 2002-08-02 Thomson Csf Systeme radio haute capacite
EP1406416A1 (fr) * 2002-10-03 2004-04-07 Agere Systems Inc. Dispositif, systhème et procédé pour diviser les functions d'un point d'acces entre un point d'acces central et plusieurs points d'acces radio moins complexes
WO2004073114A1 (fr) * 2003-02-14 2004-08-26 Nortel Networks Limited Antennes sans fil, reseaux, procedes, logiciel et services
US8351987B2 (en) 2006-09-27 2013-01-08 Dragonwave, Inc. Wireless network communication apparatus, methods, and integrated antenna structures

Citations (1)

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Publication number Priority date Publication date Assignee Title
US4578815A (en) * 1983-12-07 1986-03-25 Motorola, Inc. Wide area coverage radio communication system and method

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4578815A (en) * 1983-12-07 1986-03-25 Motorola, Inc. Wide area coverage radio communication system and method

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0962107A4 (fr) * 1997-01-17 2001-12-19 Univ California Systeme de telecommunications large bande, universel, hybride utilisant de petites cellules radio interconnectees par des liaisons optiques dans l'espace libre
FR2820257A1 (fr) * 2001-01-26 2002-08-02 Thomson Csf Systeme radio haute capacite
EP1406416A1 (fr) * 2002-10-03 2004-04-07 Agere Systems Inc. Dispositif, systhème et procédé pour diviser les functions d'un point d'acces entre un point d'acces central et plusieurs points d'acces radio moins complexes
WO2004073114A1 (fr) * 2003-02-14 2004-08-26 Nortel Networks Limited Antennes sans fil, reseaux, procedes, logiciel et services
US8351987B2 (en) 2006-09-27 2013-01-08 Dragonwave, Inc. Wireless network communication apparatus, methods, and integrated antenna structures

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