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`EUROPEAN PATENT APPLICATION
`
`(43) Date of publication:
`26.06.1996 Bulletin 1996/26
`
`(21) Application number: 95308755.8
`
`(22) Date of filing: 05.12.1995
`
`(84) Designated Contracting States:
`DE FR GB
`
`(30) Priority: 21.12.1994 US 361355
`
`(71 ) Applicant: AT&T Corp.
`New York, NY 10013-2412 (US)
`
`(72) Inventors:
`• Rudrapatna, Ashok N.
`Basking Ridge, New Jersey 07920 (US)
`• Jaisingh, Gopal K.
`Montville, New Jersey 07045 (US)
`
`(51) int. CI.6: H04Q 7/36, H04Q 7/20,
`H04Q 7/22, H04B 7/26
`
`• Miller II, Robert R.
`Convent Station, New Jersey 07960 (US)
`• Russell, Jesse E.
`Piscataway, New Jersey 08854 (US)
`• Schroeder, Robert E.
`Montville, New Jersey 07045 (US)
`
`(74) Representative: Watts, Christopher Malcolm
`Kelway, Dr. et al
`AT&T (UK) Ltd.
`5j Mornington Road
`Woodford Green Essex, IG8 0TU (GB)
`
`(54)
`
`Broadband wireless system and network architecture providing broadband/narrowband
`service with optimal static and dynamic bandwidth/channel allocation
`ent purposes depending on present allocations and
`active applications of the system. The communications
`system is designed to utilize wireless communication for
`end point delivery to both fixed and portable terminals.
`The system supplies basic telephone service, wireless
`ISDN service, wireless data service, wireless multimedia
`service and various other wireless broadband service
`including types of interactive and broadcast video.
`
`A wireless broadband communication system
`(57)
`architecture is structured to provide an array of narrow-
`band and broadband services to an end user on
`demand. The bandwidth of delivery is dynamically
`adjusted to deliver and satisfy service requirements by
`utilizing the appropriate bandwidth on demand. Band-
`width-on-demand is provided in accord with the invention
`by rearranging spectrum allocations so that a particular
`band spectrum is convertibly used to accomplish differ-
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`SERVICE
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`Printed by Rank Xerox (UK) Business Services
`2.12.4/3.4
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`

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`52 A2 EP 0 719 062 A2
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`Description
`
`Field of the Invention
`
`s
`
`This invention relates to communication system
`architectures and to a particular network architecture for
`providing narrowband/broadband
`two-way point-to-
`multipoint services to fixed and portable terminals in high
`teledensity areas. It is specifically concerned with a com-
`munication system that utilizes wireless transmission 10
`and dynamically allocates channels/bandwidth for spe-
`cific present applications.
`
`Background of the Invention
`
`15
`
`Telecommunication systems provide numerous
`services requiring both broadband and narrowband
`capabilities to the corporate and individual subscriber.
`These services normally require that each customer be
`provided with wide bandwidth communications transmis- 20
`sion media (e.g., cable or fiber) for broadband services
`and with narrowband transmission media (e.g..twisted
`pair) for narrowband services if all needed services are
`to be accommodated. This hard-wired physical media-
`based capability is expensive to install and maintain and 25
`the associated capital may be unrecoverable if the end
`user decides to change the service provider after instal-
`lation. These same costs may also limit system deploy-
`ment if these costs become prohibitive and fail to yield
`profitable life cycle economics.
`However, wireless systems have inherent flexibility
`because of their untethered nature. If the end user
`changes carriers, no capital is stranded, since the wire-
`less termination device can be recovered and rede-
`ployed.
`
`30
`
`35
`
`including interactive video and broadcast video. Further-
`more, the system provides signaling capability in support
`of all the services.
`Efficient use of spectrum is achieved at various lev-
`els of the system. At one level, channel assignment is
`performed in response to varying demand for different
`classes of service. In another aspect, conduits (which
`are subdivisions of channels) are varied in bit rate to
`accommodate service bandwidth requirements as long
`as the channels' conduits conform to an average
`throughput. In yet another aspect, service bandwidth
`requirements are matched to channels that are divided
`into high, medium and low bandwidth in order to achieve
`spectral efficiency.
`In a particular scenario making use of the invention,
`the communication system provides bandwidth on
`demand by utilizing a combination of spread spectrum
`technique (CDMA) and time division multiplexing (TDM)
`operating over a broadband spectrum that is allocated
`to specific channels on demand. The CDMA/TDM signal
`is transmitted between the system network and to a cus-
`tomer premise dynamic access director station. The use
`of CDMA/TDM along with signal compression tech-
`niques allows the use of spectrum that up until now has
`only supplied a few channels for a small subset of serv-
`ices.
`Spectral efficiency is enhanced by allocating/shar-
`ing the same bandwidth/channels to differing services
`based on a demand schedule matched to demand pat-
`terns. In another scenario using the interface, channels
`are allocated to services on a demand-driven basis.
`In addition the network architecture provides for a
`set of network servers, and signaling/control means
`between the servers and end user devices for providing
`integrated services on an end-trend network basis.
`
`Summary of the Invention
`
`Brief Description of the Drawing
`
`A wireless broadband communication system archi-
`tecture is structured to provide an array of narrowband 40
`and broadband services on demand to an end user. The
`system embodied by this invention maximizes frequency
`reuse by a judicious combination of spread spectrum
`techniques and time division multiplexing, and matching
`service requirements with appropriate sectoring of radi- 45
`ant signaling energy. The bandwidth of delivery is
`dynamically adjusted to satisfy service requirements by
`providing the appropriate bandwidth needed. Band-
`width-on-demand is provided in accord with the invention
`by rearranging (i.e. remapping) spectrum allocation to
`simultaneously achieve two objectives: (1) assign users
`channels matched to their requirements, and (2) rear-
`range channel assignments to maximize spectrum utili-
`zation. The communications system is designed to utilize
`wireless communication for end point delivery to fixed
`site customer areas and portable customer terminals.
`The system supplies basic telephone service, wireless
`ISDN service, wireless data service, wireless multimedia
`service, and various other wireless broadband services
`
`so
`
`ss
`
`FIG. 1 is a pictorial schematic of a broadband wire-
`less network topology embodying the principles of
`the invention;
`FIG. 2 is a functional schematic of a broadband wire-
`less network architecture embodying the principles
`of the invention;
`FIG. 3 is a graph of illustrative spectrum allocation
`in accord with the invention;
`FIG. 4 is a flowchart illustrating a method of static
`channel assignment to meet predictable service
`demand variations;
`FIG. 5 is a flowchart illustrating a method of dynamic
`channel assignment to meet service demands;
`FIG. 6 is a graphical depiction of the distribution of
`procedures to implement static and dynamic chan-
`nel assignments;
`FIG. 7 is a graph of an incremental channel reas-
`signment process across service classes;
`FIG. 8 shows how the spectrum is partitioned into
`channels and conduits; and
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`FIG. 9 illustrates a subchannel assignment scheme
`for servicing broadband (i.e.,video) services.
`
`Detailed Description
`
`SYSTEM NETWORK TOPOLOGY FOR WIRELESS
`NETWORK WITH SPECTRUM ALLOCATION
`
`FIG. illustrates one version of a network topology of
`a broadband wireless network embodying the principles
`of the invention. An ATM (asynchronous transfer mode)
`transfer
`network 101 and a STM
`(synchronous
`mode)network 102 are shown connected to a service
`node 103 coupled in turn to a fiber based SONET/SDH
`access ring 104. The use of a fiber based SONET/SDH
`ring for access and link purposes is for illustrative pur-
`poses and is not essential for the disclosed Illustrative
`network. A star network using non-fiber transmission,
`including point-to-point microwave and/or infrared com-
`munication could just as easily be used. Access nodes
`105-1 to 105-4 couple the SONET/SDH access ring 104
`to a plurality of access antennas or intelligent microports
`(IMP) 106-1 to 106-4. The intelligent microport 106-2 is
`shown connected by wireless to an access director or
`wireless repeater 1 07 at a residential customer premise.
`This access director/wireless repeater contains a plural-
`ity of equipment functionality [including a telephone,
`ISDN terminals data communication devices (e.g., PC),
`television/set-top boxes,
`signaling devices/adjuncts,
`multimedia worksataions, etc] supplying a broad array of
`narrowband/broadband services, each of which requires
`differing bandwidth capability. The microport 106-2 is
`also shown as directly serving a wireless handset 108
`external to the customer premise. A microport 1 06-4 is
`shown coupling service to an industrial/office site in a
`manner similar to that of the residence premises. A sat-
`ellite ground station 109 is shown connecting the
`SONET/SDH access ring 104 to a satellite 110 via
`access node 105-4. Communication between the
`SONET/SDH access ring 104 and the end user recipi-
`ents is by wireless, permitting the spectrum to be parti-
`tioned into multiple channels of sufficient bandwidth as
`required by a particular service or application.
`
`FUNCTIONAL PARTITIONING OF THE NETWORKTO
`ACHIEVE OPTIMAL SPECTRAL IMPLEMENTATION
`
`An architecture suitable for the broadband wireless
`network is shown in the FIG. 2 in terms of the communi-
`cation of the network to a particular end user. A channel
`allocation server 222 is provided to identify and store
`information regarding uses of different services over time
`to control static and dynamic reallocations of spectrum
`to individual services.
`A signaling server 213 provides signaling services
`to end user devices: Acting as a gateway between end
`user devices and the network's internal signaling sys-
`tem; distributing control data to other servers, such as
`billing/ OAM&P (operations, administration, mainte-
`
`5
`
`10
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`15
`
`nance, and provisioning) data to billing/OAM&P server;
`etc. IVOD server 21 4 supports IVOD services, enhance-
`ments to normal video; (e.g., pause, rewind etc. interac-
`tivity), menu driven user interface, etc. Billing/OAM&P
`server 215 provides for integrated billing/OAM&P to end
`users across all services taking into account any special
`service options and plans (e.g., 60 minutes of any pro-
`gram per month for a fixed fee). Security server 218 pro-
`vides for security authentication and fraud prevention
`services to service providers and to end users. Customer
`service profile server 21 6 stores end user data including
`subscriber server preferences, etc. Location and user
`registration server 217, contains real time data on a
`user's current location and service area related data.
`Signaling server 213, IVOD server 214, security
`server218, billing/OAM&P server215, customer service
`profile server 216, location and user registration server
`217 and the channel allocation server 222 are coupled
`to the ATM network 101, STM network 102, and/or the
`service node 103. The ATM network 101 and STM net-
`work 102 are connected to a service node 103 which is
`in turn connected to an access node 105-N. A national
`headend 201 is connected to the local headend 21 1 via
`a satellite 1 10 and satellite ground station 109. The local
`25 headend 21 1 is also connected to an access node 1 05-
`N. An intelligent microport (access antenna) 106-N pro-
`vides the air interface to the access director 107, which
`is in turn connected to the premise equipment or neigh-
`borhood wireless terminal 108 by either internal wiring
`30 or by a short air interface.
`The service node 103 performs traffic grooming (e.g.
`aligning radio frequency/access lines to land line trunks
`and to channels in low, medium and high arrays to sub-
`channels with low, medium and high bit rate services)
`35 and further performs circuit/synchronous transfer mode
`(STM) and cell/asynchronous transfer mode (ATM)
`switching. It is also a control for feature invocation and
`execution. The national headend 201 originates
`video/multimedia broadcast information for national dis-
`tribution. A local headend 21 1 or the access director 1 07
`receives the video/multimedia information for local dis-
`tribution. The access node 1 05-N adds and drops trunks
`to the ring/access links and provides multiplexing and
`demultiplexing capability. The intelligent microport 106-
`45 N implements both narrowband and broadband services
`by supporting a variety of multiple air interfaces. It pro-
`vides both static and dynamic channel allocation to meet
`changing service demands by providing bandwidth on
`demand. The access director 107 is a gateway/repeater
`so providing a link between the microport and customer
`premises equipment (both wireless 108 and wired). The
`neighborhood wireless terminal 108, supports a broad
`array of services including wireless multimedia services.
`
`20
`
`40
`
`55 SPECTRUM ALLOCATION AND PARTITIONING
`
`Allocation or partitioning of available spectrum in
`accord with the principles of the invention is shown in the
`figure 3. A service channel map shows how various
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`channels may be apportioned to various illustrative serv-
`ice classes. Blocks of channels each enabling a 6 or 10
`MHz bandwidth are shown arranged linearly. Two chan-
`nels 301 are shown distinct and isolated from the main
`array. These channels are dedicated to signaling for set 5
`up of connections and control of interactive commands.
`They also convey data useful in provisioning, bill-
`ing/OAM&P, and maintaining services to end users on
`an end-tend basis across all services in an integrated
`manner. This data communicated between the end user w
`terminals and the network servers (213 through 222 in
`figure 2) include user identity, destination address,
`authentication service request codes, billing options,
`OAM&P messages, security/encryption code, service
`priority, location, grades of service requested, etc. This 75
`data is used by the network servers to provide services
`to end users in accordance with service requests. Chan-
`nels 301 are wireless packet signaling channels in this
`embodiment and are comprised of two 6 MHz channels.
`In addition to utilizing channel 301, channel 308 (auxil- 20
`iary packet response channel) could be used for this sig-
`naling and control messages, based on the amount that
`such messages need to be supported. Finally in addition
`to the dedicated channels (301, 308) these messages
`could also be exchanged via the same channels (303 - 25
`307) use for the bearer services.
`The total array of bearer channels covers a span of
`198 MHz in this illustrative array. Channels 303 are nar-
`rowband service class access downlinkchannels. Chan-
`nels 304 are downlink broadcast video service channels. 30
`Channels 305 are downlink interactive video on demand
`channels. The channels designated 306 provide guard
`spectrum for duplex filters/attenuation rolloff used in the
`network. Channels 307 are uplink narrowband service
`class access channels. Channel 308 is an auxiliary 35
`packet response channel. In the illustrative embodiment,
`channels designated 301 are bounded between 2150
`MHz and 2162MHz, and channels designated 303
`through 308 are hounded between 2500 MHz and 2690
`MHz. In this embodiment, both the frequencies and the 40
`bandwidth of the channels can be adapted to meet dif-
`ferent requirements.
`
`STATIC CHANNEL ASSIGNMENT PROCESS
`
`45
`
`FIG. 4 flowcharts a process of static channel assign-
`ment. This process is repeated periodically to conform
`to the channel reassignments to known customer
`demands at specified intervals. The process assigns
`channels and bandwidth on the basis of established traf-
`f ic patterns on specific days and at specific times of day.
`The instructions of the first process block 401 monitor
`the time of day and the day of the week and identify the
`occurrences of special days that are relevant to traffic
`demands. The traffic demands are categorized as to 55
`specific services and are evaluated with an allocation
`algorithm to specify channel transfers at time Tk accord-
`ing to: CsiSj from service class si to service class sj. A
`subsequent decision block 403 evaluates the data of
`
`so
`
`block 401 to determine if static channel allocation is nec-
`essary. If it is not the flow proceeds, via terminal 409, to
`a dynamic allocation flow process shown in the figure 5.
`If a static allocation is needed the flow proceeds to
`instruction block 405 which specifies the reallocation of
`channels to meet the expected traffic demands. In the
`process the channel CsiSj is transferred from service
`class si to service class sj for all i and j where j=1 to N
`and i does not equal j and C siSj = -C SjSi . The flow then
`proceeds to the process of FIG. 5, via terminal 41 1 .
`
`DYNAMIC CHANNEL ALLOCATION PROCESS
`
`The process of dynamic assignments is described
`in the flowchart shown in FIG. 5. It begins in terminal 500
`which proceeds from the process shown in FIG. 4. The
`initial instruction block 501 defines an existing allocation
`of channels and bandwidth to services. The flow process
`begins in response to a handoff from the static process
`of FIG. 4, via terminal 502, at the entry to decision block
`503. The instruction for block 503 determines idle chan-
`nel capacity and compares the number of idle channels
`assigned to an incumbent service class (i.e. existing
`service assignments) over a specified time interval with
`a threshold of a minimum number of channel blocks A C
`that may within the the system be assigned to a different
`candidate service S j. This minimum number corre-
`sponds to the transfer increment A C discussed herein
`below with reference to FIG. 7. If the available idle capac-
`ity does not exceed this threshold, the process recycles
`to reevaluate the number of idle channels available for
`such purposes.
`If it is determined that a sufficient number of chan-
`nels exist to satisfy the threshold requirement, the sub-
`sequent decision block 505 determines if there is
`blocking on channels assigned to the candidate services
`over the same period investigated in the evaluation of the
`block 503. If no such blocking exists the flow returns to
`the input in block 503.
`If such blocking is found to exist the process flow pro-
`ceeds to instruction block 507 which controls the assign-
`ment of channels to transfer channels from service class
`si to service class sj. At the time of transfer it is deter-
`mined if all service classes si to sj have been checked
`and evaluated. If it has the flow proceeds to instruction
`block 509 which halts the flow for a specified time inter-
`val. Instruction block 509 then returns the process to the
`input of block 503 where the dynamic assignment proc-
`ess resumes.
`If all such service classes have not been evaluated,
`the flow proceeds to instruction block 51 1 which incre-
`ments i or j and the flow returns to the input of block 503
`where the dynamic assignment process resumes.
`
`NETWORK DISTRIBUTION OF SPECTRUM ALLOCA-
`TION FUNCTIONS
`
`The procedures of channel assignment are distrib-
`uted within the network system, as shown in FIG. 6, with
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`instruction block 601 being performed in the service
`node to measure channel occupancy data. The flow pro-
`ceeds to decision block 605 in the channel allocation
`server which in process block 603 estimates the blocking
`probabilities in each service classes. The flow proceeds 5
`within the channel allocation server to decision block
`605, which determines if it is necessary to reallocate
`channel assignments due to changes in static or
`dynamic conditions. The process continuously recycles
`in this block if there is no need to reallocate spectrum. If w
`there is a need to reallocate spectrum, the flow proceeds
`to instruction block 607 which identifies the channels
`Csisj tnat are t0 De moved from si to sj service classes
`according to the defined static and dynamic assignment
`processes as described in the flow charts of figures 4 15
`and 5.
`The flow proceeds to instruction blocks 609, 61 1 ,
`613 and 615 located in the service node, the access
`node, the intelligent microport and the access director,
`respectively. Instructions of block 609 assign network 20
`trunks to the access trunks. The instructions of block 61 1
`demultiplex/multiples channels or combine/split chan-
`nels to align mapping of blocks of channels. Instructions
`of block 61 3 associate wired channels with RF channels
`and instructions of block 61 5 assign channels to conform 25
`with assignments in the intelligent microport.
`
`SPECTRUM TRANSFER INCREMENTS ILLUS-
`TRATED
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`30
`
`A graphical depiction of incremental channel reas-
`signment in the system across service classes is illus-
`trated in the figure 7 in which three circular charts 701 ,
`702 and 703 each define a different category of service
`classes. Bach channel in the illustrative embodiment has 35
`a plurality of conduits of different bandwidth, with the
`conduits in each channel totaling 6 or 10 MHz. These
`conduits may be joined or separated and varied in band-
`width to form channels for specific service requirements.
`Bach conduit or group of conduits is associated with sup- 40
`porting a specific service. These conduits are time slots
`in some applications (TDM) and are part of the shared
`spectrum band in other applications (CDMA).
`The initial disk representation of disk 701 , in the illus-
`trative embodiment, represents nine channels normally 45
`assigned to interactive broadcast video services. Disk
`701 is sectorized into three 120 degree sectors each of
`which uses the same nine channels (i.e., a sectorized
`omni approach). A sectorized approach is used in place
`of omni radio signal radiation in order to use a single
`antenna for all services, to minimize power require-
`ments, and minimize heat loads on the intelligent micro-
`port. Channels that are so sectorized are in effect
`that channel sectorization
`is
`omnidirectional, so
`designed to improve signal reception quality and limit 55
`geographical area covered to the requesting subscriber.
`The chosen sectorization scheme represents a single
`sectorized antenna that will support all the service
`
`so
`
`classes depicted by the three representational graphical
`discs 701, 702 and 703.
`The channels depicted on disk 702 are normally
`dedicated to interactive video services and include three
`sectors each of which includes three channels. It is
`apparent that the minimum increment of channels that
`can be transferred between the interactive broadcast
`video disc 701 and the interactive video-on-demand disc
`702 is three channels total. The first and second discs
`701 and 702 are one way broadcast only signals from
`the intelligent micro port to the access antenna of the
`end user.
`The third disk 703 depicts the collection of ISDN,
`voice and data services with four channels, paired to
`support duplex operations (e.g. two pairs related to each
`of the three sectors). The transfer increment between
`disk 702 and 703 is two channels per sector. All the chan-
`nels on the discs 702 and 703 in the original set up are
`different in frequency from one another. The transfer
`increment between the first disk 701 and the third disc
`703 is six channels total.
`Intelligence for executing this transfer of channels
`preferably (though not necessarily) appears at the intel-
`ligent microport at the network access point. For exam-
`ple, a change of application of channels from disk 701 to
`disk 703 would require a minimum of six channels total
`to be transferred from disk 701 to the application defined
`by disk 703. These channels would be filled to accom-
`modate the new application, conduit by conduit, until the
`recipient channels were filled. Then additional channels
`(if available) would be transferred to the service requiring
`additional capacity.
`
`EFFICIENT PACKING OF SPECTRUM INTO SLOTS
`FOR SELECTIVE ASSIGNMENT
`
`The graph in FIG. 8 depicts a frequency spectrum
`divided into channels and conduits. A band of frequency
`which in this particular example is chosen to be 1 98 MHz
`and is shown divided into a number of contiguous fre-
`quency channels 801-1 to 801 -N. One of the channels
`801 -X is shown in an exploded view to comprise several
`conduits 802-1 to 802-M which are smaller frequency
`bands dividing a channel. The frequency band of each
`channel 801 in the illustrative embodiment is either six
`or ten MHz. Since the bandwidth demands of different
`services vary, conduits may be dynamically altered in
`size (i.e.,bandwidth) to match the requirements of the
`various services they support. In some instances a sin-
`gle conduit will suffice whereas in others several conduits
`may be assigned to a service. The optimum number of
`conduits assigned to a service is determined by the
`demand for that service.
`Each channel is assigned to a specific service class
`at any given time. Services within a service class can
`share access to the channels assigned to that service
`class (i.e. , use any of the conduits of that channel) on an
`unprovisioned (i.e., not preallocated) dynamic basis. In
`the allocation scheme a channel is comprised of several
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`conduits and a conduit is the physical or logical partition-
`ing of a channel. A conduit is the basic unit to provide
`service to any service class. In the IVOD and IBV service
`classes, the wireless modulation schema is TDM time
`slots corresponding to a physical partitioning of spec- 5
`trum. For narrowband service classes, CDMA is the wire-
`less modulation schema in which individual conduits are
`in effect logical parts of the overall channel. In each
`instance, a service assignment is handled by conduits
`wherein each conduit is assigned to serving a user of a w
`program.
`
`OPTIMIZING ASSIGNMENT BASED ON PROGRAM
`CONTENT REQUIREMENTS
`
`15
`
`A division of spectrum of channels into high (921-1 ,
`921-2, 921 -H), medium (911-1, 911-2, 911-M) and low
`(901-1 , 901-2, 901 -L) bit rate applications for video serv-
`ices is illustrated in the FIG. 9. The video content is
`encoded using the emerging MPEG (motion picture 20
`expert group) II standard, that operates over a broad
`range of encoding rates (aproximately 1 .544-9 Mbps).
`Different program content is encoded optimally at differ-
`ent rates (e.g., movies at lower rates, sports at higher
`rates). Decoding MPEG II sources at variables rates is 25
`automatically handled in the MPEG II standard. Some
`channels are allocated for lower rate encoding, some for
`medium rate encoding and some for higher rate encod-
`ing. The number of channels assigned to each of these
`program types is based on the program mix required at 30
`that time. Such allocations can be preset for static allo-
`cation based on time of day and day of week or for
`dynamic allocation on a real time basis as program con-
`tent changes are required without prior arrangement.
`Video programs may be groomed (i.e., channeled) to 35
`appropriate channels based on bandwidth requirements.
`As video programs are reassigned to different channels
`and conduits (i.e. channel x and conduit y) that informa-
`tion is conveyed to the access director by the IMP. In one
`illustrative embodiment it is conveyed as a mapping 40
`table.
`Within a bit rate video service type, programs are
`encoded at variable rates (within a narrow range around
`the base average rate specified for the channel based
`on the program content requirements (e.g., based on the 45
`amount of motion in the video picture) in a manner that
`balances bit rate assignments across all the programs
`within that channel (e.g., in the 3 Mbps video channel
`type, one program may be given 2.7 Mbps and another
`one 3.3 Mbps at one time, and perhaps reversed later,
`keeping the average across programs to 3 Mbps at all
`times). To facilitate such an approach, a packetized
`scheme (i.e., ATM or another packet arrangement) is
`used because of its inherent bandwidth on demand
`capability.
`The ben