~R.IGINAL
`
`~flLE
`Before the
`FEDERAL COMMUNICATIONS COMMISSION
`Washington, D.C. 20554
`
`ORIGINAL
`
`ET Docket No. 92-10
`PP-37
`
`)
`
`))
`
`)
`)
`)
`)
`)
`)
`
`In the Matter Of:
`
`Mobile Telecommunication
`Technologies Corporation
`
`Request for a Pioneer's Preference
`Regarding its Petition for Rulemaking
`to Allocate Three 50 kHz Channels in the
`930-931 MHz Band and to Establish Rules and
`Policies for a New Nationwide Wireless
`Network (NWN) Service
`
`TECHNICAL FEASIBILITY DEMONSTRATION
`
`Jai P. Bhagat
`Executive Vice President,
`MOBILE TELECOMMUNICATION
`TECHNOLOGIES CORP.
`and President,
`MTEL TECHNOLOGIES CORP.
`Security Center -- South Building
`200 South Lamar Street
`Jackson, Mississippi 39201
`(601) 944-1300
`
`No. of Copies rec'd ()~ ~
`UstABCDE
`
`Of Counsel:
`
`Richard E. Wiley
`R. Michael Senkowski
`David E. Hilliard
`Eric W. DeSilva
`of
`WILEY, REIN & FIELDING
`1776 K Street, N.W.
`Washington, D.C. 20006
`(202) 429-7000
`
`Dated:
`
`June 1, 1992
`
`Juniper Ex 1009-p. 1
`Juniper v MTel891
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`

`

`TABLE OF CONTENTS
`
`SUMMARY
`
`I.
`
`II.
`
`Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
`
`The Nationwide Wireless Network System
`
`III. Mtel's Innovative Use of Enhanced Multitone Modulation Techniques Is
`Technically Feasible . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
`
`i
`
`2
`
`4
`
`6
`
`IV. Mtel's Advanced Dynamic Frequency Management Scheme Is
`Technically Feasible . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11
`
`V.
`
`VI.
`
`Mtel's Ongoing NWN Validation Program
`
`Conclusion
`
`EXHIBIT A - Transmitter Parameter Characterization
`For NWN
`
`18
`
`21
`
`TAB A
`
`EXHIBIT B - Performance and Efficiency Considerations
`For the Mtel Nationwide Wireless Network (NWN) Protocol
`
`. . . . .. TAB B
`
`EXHIBIT C - Mtel NWN User Device Product Feasibility
`and Cost Analysis
`
`EXHIBIT D - MPR Teletech Qualifications
`
`TAB C
`
`. TAB D
`
`EXHIBIT E - NWN Architecture and Operations . . . . . . . . . . . . . . . . .. TAB E
`
`EXHIBIT F - Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . .. TAB F
`
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`

`SUMMARY
`
`Paging services have been an enormous success story. Over twelve million
`
`Americans benefit from the ability to be reached on the move through these basic, low
`
`cost telecommunications services. Mtel, as a technological innovator, pioneered and
`
`deployed the country's first nationwide service. As a result, a ubiquitous network
`
`exists that can reach anyone, virtually anywhere, at anytime.
`
`Mtel's proposed Nationwide Wireless Network ("NWN") service transcends
`
`existing technological limitations to introduce the next generation of advanced
`
`messaging services. Today's paging services are strictly one-way and typically limited
`
`to 1,200 bps. Tomorrow's NWN service would shatter these constraints:
`
`•
`
`•
`
`Speed. NWN will support extensive high speed messaging at up to 24,000 bps
`to facilitate a high capacity nationwide service.
`
`Two-Way Functionality. NWN will support multiple levels of reverse channel
`service depending upon the specific requirements of the end user -- automatic
`acknowledgement from portables that a message has been received to support
`"return receipt requested" applications; user-interactive simple preformatted
`acknowledgements to confirm messages have been received by the end user;
`and, full two-way transfer capability for short and extended length digital data.
`
`• Nationwide Coverage. NWN offers transparent nationwide coverage familiar to
`today's users of wide area and nationwide paging systems. NWN will also
`support seamless interconnection with AMSC's mobile data services to provide
`coverage even in the most remote areas.
`
`• Application Independence. NWN offers an application independent digital data
`transmission service that can be customized for each user's requirements.
`
`• Adaptable Functionality. NWN supports variable levels of error detection and
`correction capability, as well as encryption, prioritization, and many billing
`options depending upon each end user's requirements.
`
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`•
`
`Support for Industry Standards and Customized Needs.
`Interfaces supporting
`numerous industry standards are planned to allow the broadest compatibility
`between NWN and wireline messaging systems. Specialized arrangements will
`also be available to support specific needs for customers.
`
`Thus, NWN offers an unprecedented leap forward in messaging capabilities coupled
`
`with national two-way functionality!
`
`The implications of NWN are enormous. Mtel's proposal would allow
`
`consumers to carry the power of a sophisticated national network on their person.
`
`NWN would provide a ubiquitous, immediate infrastructure for "telecomputing" and
`
`information services interacting with both inexpensive portable data devices and
`
`personal computers. Paging would be transformed into its full 21st Century messaging
`
`potential.
`
`The key to future national messaging services lies in a number of technological
`
`innovations pioneered by Mtel. NWN introduces the following notable advances that
`
`integrate simulcasting and frequency re-use systems to produce enormous gains in data
`
`rates, spectrum efficiency, and network functionality:
`
`• Enhanced Multitone Modulation. NWN relies on high dimensionality
`multicarrier modulation techniques to go beyond simulcast data barriers and
`achieve transmission rates up to 24,000 bits per second -- 10 times faster than
`the fastest existing simulcast systems (2,400 bps), a technology also pioneered
`by Mtel.
`
`•
`
`Simulcast Zoning. Relying on an intelligent centralized network architecture,
`NWN utilizes a highly spectrum efficient zoned network that retains the
`significant benefits of simulcast while allowing extensive frequency re-use and
`graceful expansion capability.
`
`• Multiple Receiver Load Balancing. Mtel has developed a protocol that allows
`its central computers to track the location of portables, simultaneously
`scheduling reverse channel transmissions on each receiver in the network to
`permit extensive frequency re-use.
`
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`• Dynamic Scheduling. NWN transmissions are designed to offer the greatest
`practical degree of flexibility to the system controller to alter the allocation of
`system resources in real time, efficiently accommodating variations in the
`balance of forward/reverse, nationwide/zonal, address group, and
`scheduled/unscheduled reverse channel traffic.
`
`• Contention Priority Ordered Demand Assignment of Resources. Mtel has
`developed a flexible, dynamic transmission protocol that optimizes use of the
`reverse channel by minimizing the effects of unpredictable contending portable
`transmission requests.
`
`• Adaptive Registration. Mtel's use of Intelligent Network functionalities permit
`the NWN system to utilize real time data acquired on customers' usage patterns
`to maximize efficiency in locating portables by dynamically altering registration
`schemes "over the air. "
`
`Collectively and individually, these innovations result in a service that offers highly
`
`spectrum efficient wireless messaging capability, flexibility to accommodate a wide
`
`range of consumer needs, and the use of low cost portable units with extended battery
`
`life.
`
`In order to demonstrate the technical feasibility of the NWN innovations, Mtel
`
`has undertaken a comprehensive program of laboratory research, computer modeling
`
`and field testing. MPR Teletech Ltd, a leading telecommunications research and
`
`development company, has evaluated and confirmed the theoretical underpinnings of
`
`Mtel's proposal in extensive studies appended to this submission. Finally, Mtel's
`
`aggressive field test program for verifying NWN's capabilities is underway and
`
`progress reports will be submitted to the Commission at each major benchmark.
`
`The extensive efforts reflected in this Technical Feasibility Demonstration
`
`document the technical feasibility, technological innovations and public importance of
`
`Mtel's NWN service proposal. Accordingly, prompt and favorable action on Mtel's
`
`Pioneer Preference Request is respectfully requested.
`
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`Juniper Ex 1009-p. 5
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`

`

`Before the
`FEDERAL COMMUNICATIONS COMMISSION
`Washington, D.C. 20554
`
`RECEIVED
`JUN - 11992
`
`FEDERAl.. eat'tUNICATIONS COMM/SSfOO
`OFFICEOF THESECRETARY
`
`ET Docket No. 92-100
`PP-37
`
`)
`
`))
`
`)
`)
`)
`)
`)
`)
`
`In the Matter Of:
`
`Mobile Telecommunication
`Technologies Corporation
`
`Request for a Pioneer's Preference
`Regarding its Petition for Rulemaking
`to Allocate Three 50 kHz Channels in the
`930-931 MHz Band and to Establish Rules and
`Policies for a New Nationwide Wireless
`Network (NWN) Service
`
`TECHNICAL FEASIBILITY DEMONSTRATION
`
`Mobile Telecommunication Technologies Corporation ("Mtel") hereby submits
`
`its response to the Commission's public notice of April 30, 1992. 1 This notice set a
`
`cut-off date of June 1, 1992 for each pioneer's preference applicant to submit its
`
`"demonstration[s] of technical feasibility or preliminary experimental results." 2 As
`
`discussed below, Mtel is in the midst of a massive ongoing effort, including laboratory
`
`research, computer modeling, independent analysis, and field testing, to validate all
`
`aspects of the NWN proposal. The results of this development program to date,
`
`described in the four technical attachments, validates the feasibility of the innovations
`
`identified in Mtel's NWN proposal and the ability of Mtel to bring the NWN service to
`
`See Deadline To File Pioneer's Preference Requests 900 MHz Narrowband Data and Paging
`Service (ET Docket No. 92-100), Public Notice, Mimeo 22922 (April 30, 1992).
`
`2
`
`Id.
`
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`- 2 -
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`the public. Mtel believes its pioneering efforts and innovations, individually and
`
`collectively, warrant grant of a pioneer's preference.
`
`I.
`
`INTRODUCTION
`
`Mtel and its corporate predecessors consistently have pioneered significant
`
`messaging developments. As discussed in its previous filings in this docket, Mtel has
`
`extensive experience in designing, constructing, and operating high technology wireless
`
`communications services. 3
`
`In the early 1980's, Mtel was actively involved in the FCC
`
`proceedings regarding allocating spectrum for a nationwide paging service. Mtel was
`
`convinced that consumers would respond favorably to a high quality nationwide
`
`service. Eventually, Mtel's subsidiary, SkyTel, Inc. (IfSkyTeFMIf), was awarded the
`
`first nationwide paging license at 931.9375 MHz,4 and was the only one of the three
`
`original permittees that successfully built and launched a nationwide paging service.
`
`Other companies and the user public are now benefitting from the technical trail Mtel
`
`has blazed.
`
`Mobile Telecommunication Technologies Corporation Petition for Rulemaking to Allocate 150
`kHz in the 930-931 MHz Band and to Establish Rules and Policies for a New Nationwide Wireless
`Network (NWN) Service at 1-4, ET Docket No. 92-100, RM-7978 (filed November 21, 1991)
`(proposing to allocate three 50 kHz channels for competitive NWN carriers) ["NWN Petition"]. Mobile
`Telecommunication Technologies Corporation Request for a Pioneer's Preference Regarding its Petition
`for Rulemaking to Allocate 150 kHz in the 930-931 MHz Band and to Establish Rules and Policies for a
`New Nationwide Wireless Network (NWN) Service at 2-3, ET Docket No. 92-100, PP-37 (filed
`November 21, 1991) ["NWN Preference Request"].
`
`The license was awarded in 1985 to National Satellite Paging. Since that time, the ownership of
`4
`the company and the name have changed but the original senior management of the controlling
`corporation has remained. The name was officially changed to "SkyTelTllII in 1989. At present, Mtel
`owns approximately 91 percent of SkyTelTll and the remainder is owned by Radiofone, Inc.
`
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`- 3 -
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`Development of the nationwide simulcast paging service involved integrating a
`
`number of systems using sophisticated central computer technology, toll-free access, a
`
`spread-spectrum VSAT satellite interconnection system, and several monitoring and
`
`alarm functions to ensure maximum reliability and minimum downtime. Because no
`
`paging terminal was available that would meet the needs of its nationwide paging
`
`system, Mtel developed the architecture and software to control a paging system
`
`through a general purpose computer. Mtel's more recent accomplishments include
`
`announcing the nation's first 2,400 bps simulcast messaging technology,S and
`
`providing nationwide one-way wireless electronic mailbox ("e-mail tl
`
`) service to AT&T
`
`SafariTH computers and HP-95LX palmtop computers through the SkyTelTH network. 6
`
`In addition, Mtel has exported technologies to Asia, Canada, and Mexico to facilitate
`
`nationwide paging in other countries and to implement seamless international
`
`messaging. 7
`
`In keeping with this tradition of innovation, on November 21, 1991, Mtel filed
`
`its petition for rulemaking proposing the use of three 50 kHz channels in the 930-931
`
`MHz band for a new Nationwide Wireless Network ("NWN") service. 8 Mtel's NWN
`
`5
`
`See Telocator Bulletin, Vol. 91 No. 32, p. 2 (August 11, 1991).
`
`In this service, AT&T's Easylink'l1l electronic mail service is linked to SkyTel'l1l via a gateway
`6
`and permits users to send mail to computers equipped with a low cost adapter. Although somewhat
`analogous to the proposed NWN service in terms of ease of use and area of operation, NWN will be a
`fully two-way service, unlike the one-way service now available.
`
`Today, systems in Mexico, Canada, and Singapore operate with computer systems integrated by
`7
`Mtel using software developed by Mtel. SkyTel'l1l and these systems are linked to Mtel's global network
`computer center to offer international messaging. Systems are under development in Hong Kong,
`Bermuda, Malaysia, and other countries.
`
`8
`
`NWN Petition.
`
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`- 4 -
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`Petition proposed use of sophisticated innovative modulation techniques and an
`
`innovative advanced dynamic frequency management scheme to provide highly efficient
`
`two-way messaging capabilities for laptop, palmtop, and other portable computing
`
`devices. At the same time, Mtel filed a request for a pioneer's preference to recognize
`
`these innovations that Mtel developed to implement this ground breaking new service. 9
`
`II.
`
`THE NATIONWIDE WIRELESS NETWORK SYSTEM
`
`NWN provides an inexpensive mobile communications solution for store and
`
`forward compatible computer applications. For the numerous data communications
`
`users who do not need radio-based virtual circuit services, this store and forward
`
`messaging economically and efficiently optimizes the use of the radio channel. Given
`
`the growing popularity of e-mail and packet-based networks in the "wired" world, Mtel
`
`expects extensive demand for NWN, which operates in a portable radio environment.
`
`Mtel has relied on several innovative technologies to create an economic and
`
`efficient messaging service. First, Mtel's NWN system pioneers use of enhanced
`
`multitone modulation techniques to achieve simulcast bit rates as high as 24,000 bits
`
`per second. This rate is an order of magnitude faster than the current state-of-the-art
`
`for implemented simulcast paging systems, which is 2,400 bits per second. 10 Mtel
`
`9
`
`NWN Preference Request.
`
`10 Most existing simulcast paging systems operate at rates of 1200 bits per second or less. During
`1991 Mtel pioneered the development of 2400 bps technology for the industry. Mtel is currently
`deploying this technology for its SkyTelTII network. NWN will also operate at a faster data rate than the
`forthcoming European Radio Messaging System ("ERMES"), which will deliver data at 6,250 bps. Mtel
`is participating in the implementation of ERMES through its United Kingdom subsidiary.
`
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`- 5 -
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`believes this improvement over existing systems is a significant achievement, since it
`
`required Mtel to develop high dimensionality, simulcast-compatible signalling
`
`techniques due to the 3,000 baud practical limitation on simulcast systems. ll
`
`Second, Mtel's NWN system will deploy an innovative advanced dynamic
`
`frequency management ("ADFM") scheme to optimize efficient spectrum usage.
`
`Mtel's ADFM protocols will implement a number of efficiency-enhancing features,
`
`including use of (1) dynamic zoning for forward channel frequency re-use, (2) multiple
`
`receiver load balancing for reverse channel frequency re-use, (3) comprehensive
`
`dynamic scheduling, (4) contention priority ordered demand assignment ("CPODA")
`
`reverse channel resource allocation, and (4) adaptive registration. Made possible by
`
`the high speed forward channel transmission scheme and centralized intelligent
`
`network, these features optimize channel usage by portables and base stations, thus
`
`efficiently utilizing spectrum. The same features also extend battery life, thereby
`
`enhancing the utility of the service.
`
`Mtel is in the midst of a significant validation program to test and refine these
`
`innovations that includes laboratory research, computer simulation, independent
`
`analysis, and field work under its recently granted experimental license. 12 Mtel has
`
`employed the computer modeling resources of MPR Teletech Ltd ( t1 MPR") to assist
`
`Mtel in validating the feasibility of the NWN innovations. MPR, with over 500
`
`The baud rate differs from the bit rate in that the baud rate specifies the rate at which symbols
`11
`can be transmitted, and the bit rate specifies the throughput achieved by decoding the symbols into a
`binary stream.
`
`12 Mobile Telecommunication Technologies Corporation Experimental Radio Authorization
`KK2XIO, File No. 2353-EX-PL-91 (April 6, 1992).
`
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`- 6 -
`
`engineers, is a leading North American telecommunications research and development
`
`facility.13 MPR's findings are summarized in three attachments: Exhibit A, titled
`
`"Transmitter Parameter Characterization for NWN"; Exhibit B, titled "Performance
`
`and Efficiency Considerations for the Mtel Nationwide Wireless Network (NWN)
`
`Protocol"; and Exhibit C, titled "Mtel NWN User Device Product Feasibility and Cost
`
`Analysis." MPR's qualifications are included as Exhibit D.
`
`In addition, Mtel has also
`
`included as Exhibit E, titled "NWN Architecture and Operations," an overview of its
`
`ongoing development of the architecture and information management systems within
`
`NWN. As discussed below, the conclusions reached in these materials demonstrate
`
`that Mtel's ongoing program has validated the feasibility of implementing an NWN
`
`system as described in Mtel's NWN Petition.
`
`III.
`
`MTEL'S INNOVATIVE USE OF ENHANCED MULTITONE
`MODULATION TECHNIQUES IS TECHNICALLY FEASIBLE
`
`High speed simulcasting is matched ideally with the coverage, spectrum, and
`
`functional requirements of the NWN service. 14 However, as discussed in Mtel' s NWN
`
`13 MPR has research and development roots extending over 80 years through its predecessor, GTE
`Lenkurt Electric (Canada) Ltd. MPR's extensive experience covers a broad range of technologies and
`services, including:
`(1) microwave radio, satellite, emergency, aeronautical, and infrared
`communications; (2) network management, supervisory and signalling, and imaging systems; (3) systems
`integration; and (4) manufacturing. MPR has recently been engaged in performing in-depth studies on
`the performance of wireless technologies for its parent, BC Tel, including cellular CDMA, cellular
`TDMA, CT-2+, and other new mobile data technologies.
`
`14 As discussed in the NWN Petition at 14-15, A4-A5 & B1-B8, simulcast improves the quality of
`coverage by overcoming shadowing and permits simpler, less expensive expansion of coverage because
`there is no need to alter the existing time or frequency usage patterns of adjacent transmitters.
`Moreover, if properly designed and implemented, simulcast effectively provides in-band frequency
`diversity to combat multipath fading.
`
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`- 7 -
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`Petition, there is a practical limitation on simulcast operations of 3,000 baud due to the
`
`time delay spread of signals from multiple transmitters. 1S
`
`In order to provide
`
`sufficient channel capacity to support NWN operations under this baud constraint, Mtel
`
`has pioneered the development of enhanced multicarrier modulation ("MCM")16
`
`techniques,17 which modulate several subcarriers at baud rates low enough to avoid
`
`serious degradation due to simulcast operation. 18 As discussed below, MPR's
`
`computer simulation analysis has confirmed that the MCM techniques under
`
`consideration will function robustly in a simulcast environment at high data rates and
`
`can be deployed in a relatively small channel without affecting adjacent channel
`
`operations.
`
`As an initial matter, achieving a practical simulcast rate of 3,000 baud is not a
`
`simple task.
`
`In order to reduce the levels of intersymbol interference to a minimum,
`
`15
`
`See NWN Petition at B2-B4.
`
`In Mtel's NWN Petition and NWN Preference Request, Mtel described these techniques
`16
`generically under the name "enhanced multitone modulations. n MPR's studies refer to these techniques
`as "multicarrier modulation" or "MCM." To retain consistency throughout this pleading and the
`exhibits, Mtel is referring to enhanced multitone modulations as "MCM."
`
`17 MCM techniques are high dimension signals that transmit more than one bit per baud interval.
`In "clean" channels, such as point-to-point microwave or telephone cable, the stock high dimension
`signals are Quadrature Amplitude Modulation (QAM) or Multi-Phase Shift Keying (M-PSK) of a single
`carrier. For the "dirty" environment (i.e., subject to greater variations in noise, circuit length, and
`multipath phenomena) found in the portable radio messaging service a more robust modulation format is
`needed. Multi-tone modulation schemes have been used before when faced with poor channels, e.g., the
`KINEPLEX and KATHRYN HF radio modems. Mtel's use of MCM in a commercial mobile radio
`environment, however, appears to be unique.
`
`An alternative approach, used in many recent systems, employs various adaptive equalizers
`18
`and/or decision directed filters. However, adaptive equalization does not appear to be appropriate for the
`NWN service at this time. The start-up training preambles required and the high cost and power
`consumption of the equalization circuitry are not compatible with the relatively short messages NWN
`sends to a large number of low cost, battery operated, portable transceivers.
`
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`- 8 -
`
`Mtel proposes to use satellite distribution of data and precise time synchronization as
`
`well as meticulous transmitter design. The combination of these two factors is
`
`expected to reduce the time delay spread to approximately 80 jJ.sec.19 With a time
`
`delay spread of 80 jJ.sec, MPR's performance simulation of an MCM technique known
`
`as multi-tone on-off keying (IMOOK")20 indicates that individual subcarriers can be
`
`modulated in a simulcast environment at a rate of 3000 baud. After generating "eye
`
`diagrams II21 while varying (1) the simulcast time delay, (2) the levels of received
`
`power from two simulcast transmitters, and (3) the fixed frequency offsets between the
`
`transmitters, the analysis of the modeling concluded specifically that "[MOOK] is
`
`capable of excellent performance in a simulcast environment, and implementation of a
`
`modem using this technique is feasible. 1122
`
`MPR also has assisted Mtel by modeling, in Part II of its NWN transmitter
`
`parameter characterization, the intermodulation products that are generated by multiple
`
`subcarriers within a small bandwidth. Several relevant conclusions are stated in MPR's
`
`analysis of the calculated intermodulation products:
`
`This represents an improvement of 2 1/2 times over existing simulcast paging systems, where
`19
`time delay spread is generally 200 ",sec. Mtel discussed the relationship between time delay spread and
`baud rate in Exhibit B to the NWN Petition.
`
`20 Mtel has previously described the signal characteristics of MOOK. See NWN Petition at A5 -
`
`A7.
`
`An "eye diagram" is the summation, over a number of baud intervals, of a data signal. The eye
`21
`opening is a measure of the ease with which a circuit could accurately register the current data value.
`
`See Exhibit A at I. MPR did not have the data or time to simulate orthogonal carrier spacing, a
`22
`technique where the data rate f. in baud is equal to the spacing f. in Hertz between subcarriers. MPR
`modeled subcarriers using a spacing of 4.5 kHz, which is 1.5 times the data rate and thus "non(cid:173)
`orthogonal." While orthogonal systems offer spectral efficiencies, radio experimentation in the field will
`be required to confirm that orthogonality can be maintained in a simulcast environment.
`
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`- 9 -
`
`•
`
`•
`
`"Using conservative assumptions on carrier spacing, MPR was able to show that
`5 modulated carriers (3 kbps BPSK) can be placed in a 50 kHz bandwidth with
`readily available Class A amplifiers using appropriate back-off techniques.
`Hence 5 carriers each carrying 3 kbaud is demonstrably achievable. ,,23
`
`"MPR's modelling showed that readily available Class A amplifiers using
`appropriate back-off techniques allow approximately half of the authorized
`bandwidth to be occupied with modulated signal (e.g. 22.5 kHz out of 50 kHz
`was modelled).
`If, instead of the conservative spacing used in the modelling,
`orthogonal spacing of the carriers were to be used, higher bit rates could be
`achieved.
`In this case, 8 carriers with 3 kbps MOOK modulation would be able
`to carry 24000 bps while falling close to the proposed mask. MPR was unable
`in the time available to model such a scheme, and cannot comment on its
`expected performance. ,,24
`
`MPR's modeling is strong support that Mtel can achieve data rates up to 24,000 bps.
`
`At a minimum, MPR's computer simulations have established a baseline by noting that
`
`"[u]sing conservative assumptions on carrier spacing" and "readily available Class A
`
`amplifiers," a data rate of 15,000 bps is "demonstrably achievable" within the
`
`emissions mask proposed by Mtel.
`
`Mtel believes its continuing validation program will improve upon this baseline
`
`data rate to achieve a projected 24,000 bits per second rate. The following avenues are
`
`being pursued in Mtel's program and, singly or in combination, should yield the
`
`desired data rate:
`
`(1)
`
`Orlhogonal Placement of Carriers. MPR could not model the advanced
`"orthogonally" spaced signals Mtel originally proposed; i.e., subcarriers
`with spacing equal to the data rate. Given the conclusion from MPR's
`simulations that the modulation products are relatively insensitive to the
`number of subcarriers in the "modulation bandwidth," reducing the
`spacing between subcarriers appears feasible. MPR states, using
`
`23
`
`24
`
`Exhibit A at 1.
`
`Exhibit A at 1.
`
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`orthogonal spacing, lithe prior discussed occupancy of 22.5 kHz could
`yield 22.5 kb/s of data. 1125
`
`(2)
`
`(3)
`
`Linearized Amplifiers. MPR's modeling assumed the use of "readily
`available" Class A amplifiers. Newer amplifiers, using memory-mapped
`predistortion, feedback and feedforward, promise "increased percentage
`bandwidth utilization." In fact, MPR notes that the data sheet for one
`vendor's feedforward amplifier reports intermodulation levels below -60
`dBc, which "would appear to be consistent with 24000 bits per second
`transmission. 1126
`
`Orlhogonal Modulation. 27 MPR's modeling suggests that the use of
`orthogonal modulation schemes, like Quadrature Amplitude Modulation
`("QAM"), may be appropriate. In this regard, MPR states "[ilt seems
`reasonable to conclude that such schemes would support a rate of 24,000
`bps. "1128
`
`Under these conditions, Mtel is convinced that 24,000 bps is a technically feasible and
`
`achievable data rate using enhanced multitone modulation techniques.
`
`As a final matter, MPR evaluated the projected costs for NWN portable data
`
`devices. Pursuant to Mtel's specifications, MPR modeled the costs of both a stand-
`
`alone portable NWN unit ("PDT") and an NWN wireless "modem" ("PDM") to be
`
`used in conjunction with a laptop personal computer or a palmtop organizer. MPR's
`
`initial evaluation of PDT and PDM costs are well within the originally targeted ranges,
`
`25
`
`Exhibit A at II-11.
`
`Exhibit A at II-IO.
`
`The meaning of "orthogonal" in modulation terminology is different from "orthogonal" in carrier
`T1
`spacing terminology.
`"Orthogonal modulation" signifies schemes where a single carrier is modulated
`with two orthogonal signals -- the I (in-phase) and Q (quadrature) signal.
`"Orthogonal spacing," in
`contrast, signifies carriers modulated at a symbol rate f. symbols per second and spaced at a frequency f.
`in Hertz.
`
`28
`
`Exhibit A at 2.
`
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`with wholesale prices estimated at $299 for the PDM and $380 for the PDT.29 Mtel
`
`will continue to experiment with further developing the network to lower costs for the
`
`devices. 30 In sum, the analysis of MPR's modeling indicates that NWN portables can
`
`be produced within the original price constraints envisioned for NWN.
`
`IV.
`
`MTEL'S ADVANCED DYNAMIC FREQUENCY MANAGEMENT
`SCHEME IS TECHNICALLY FEASIBLE
`
`Mtel's NWN system utilizes an advanced and flexible architecture to achieve
`
`spectrally efficient operations.
`
`In order to implement the architecture, Mtel developed
`
`a comprehensive set of protocols to manage information flow and control system
`
`resources. Mtel has made significant progress in verifying the performance of these
`
`protocols.
`
`In conjunction, these protocols will allow NWN to:
`
`(1) utilize a nationwide
`
`and zonal format for forward channel frequency re-use, (2) employ base receivers on
`
`an individual basis to permit reverse channel frequency re-use, (3) control dynamically
`
`access to system resources, (4) minimize inefficiencies caused by contention inherent in
`
`portable generated requests to transmit, and (5) tailor location tracking schemes for
`
`optimal use of resources. As discussed below, the NWN architecture and the protocols
`
`developed by Mtel permit an unprecedented level of system optimization that will
`
`Exhibit Cat 4. MPR has experience in CAD, prototyping, testing and manufacturing of modem
`29
`and baseband equipment for satellite and terrestrial radio systems. MPR, in fact, has access to excellent
`manufacturing facilities within the BC Tel Group of companies, as well as its own resources for small
`volume complex and/or prototype manufacturing.
`
`30 Mtel believes it may be feasible, for example, to reduce the transmit power of the portables to 1
`watt rather than 2 watts.
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`enable implementation of a system supporting a large number of users in a highly
`
`- 12 -
`
`efficient manner.
`
`Forward channel frequency re-use. Current wide area radio systems use either
`
`multichannel re-use operation or simulcast operation -- NWN combines both to obtain
`
`the maximum capacity, and thus provide superior spectral efficiency as compared to
`
`either utilized alone.
`
`In effect, NWN forward channel transmissions are divided into
`
`nationwide and zonal batches. As a precious resource, nationwide packets are used
`
`efficiently -- as necessary to locate portables that have changed zones and to deliver
`
`traffic to portables that are between zones. 31 Using this scheme, the NWN system
`
`can easily combat saturation by shifting zone boundaries or creating additional zones by
`
`changing the signals relayed by a set of transmitters during the zonal portions of the
`
`cycle. No transmitter (or receiver) re-tuning is necessary. 32
`
`Multiple receiver load balancing. NWN's independent simultaneous use of the
`
`multiple receivers in each zone significantly increases the reverse channel capacity of
`
`The power of this combination of zonal and nationwide simulcast can best be appreciated by
`31
`considering the alternatives. Without simulcast, the entire channel capacity would have to be divided into
`a number of disjointed (orthogonal) subchannels, formed in time or frequency. Each subchannel would
`only contain a fraction of the total capacity. Each transmitter would have to be assigned to a subchannel
`that was not reused by any adjacent transmitters and the portable terminals would need a means (e.g.,
`scanning) to determine the subchannel they should use. Typical deployments of such technology use a
`minimum of seven subchannels to insure that there is adequate separation. To get back to par with the
`spectral efficiency of a simulcast system, a given zone would have to be divided into at least 7 cells and
`each of these cells would have to be equ