Lipoff Exhibit 9
`10/20/15
`
`C-Cation 2025
`Arris Group, Inc., and Cox Communications, Inc. v. C-Cation Technologies, LLC
`IPR2015-00635
`1
`
`

`
`'l!Q)A.~.II1.'!1Q)"W!!;.(!..l!£ ~~ H~E1N!!J.~ SJ!Mffi, {[PM!E!;j
`
`UNITED STATES DEPARTMENT OF COMMERCE
`United States Patent and Trademark Office
`
`November 13,2013
`
`THIS IS TO CERTIFY THAT ANNEXED IS A TRUE COPY FROM THE
`RECORDS OF THIS OFFICE OF THE FILE WRAPPER AND CONTENTS
`OF:
`
`APPLICATION NUMBER: 081276,534
`FILING DATE: July 18,1994
`PATENT ~'UMBER: 5,563,883
`ISSUE DATE: October 08, 1996
`
`By Authority of the
`t:nder Secretary of Commerce for Intellectual Property
`and Director of the United States Patent and TnHicmarkOflice
`
`\ 1/Jt!dudMJ
`
`r( WrtLlAMS
`Certifying Officer
`
`2
`
`

`
`5563883
`1111111111/~l~llj~~~/1/1 ~Ill /ill/Ill
`
`;J~
`DATA*******************¥*
`
`~ALEXANDER
`
`z i **CONTINUING
`
`VERIFIED
`
`rJ.-....._
`**FOREIGN/PCT APPLICATIONS************
`VERIFIED
`f:;-1'"'
`
`DYNAMIC CHANNEL MANAGEMENT AND SIGNALLING METHOD
`
`fi~~P~~~c~·~·~·~
`~~~iJ;.~ - ~
`
`Label
`Area
`
`(Rev 6/92)
`
`Assistant Examiner
`
`j
`__ ,
`(; J•/ (
`~~-W..uJ5-< ( lJ. c)'"/;0-w.d-
`1/).b{)J
`BENEDICT V. SAFOUREK
`PRIMARY EXAMINER
`GROUP 263
`
`Examiner
`
`WARNING:
`
`Tt~e l">forn:at.cn dJsclosad herein rnay be restrie1ed. unauthorized disclosure may be
`by the ~1r.ted Stales Code T.tia 35, Sections 122, 181 and 368. Possession outside
`Patem & Trade!Tle.rX Offlce 1s restrle1ed to authorized employees and contracton; only.
`
`(FACE)--
`
`\
`
`3
`
`

`
`PATENT APPLICATION SERIAL NO.
`
`~~/276534
`
`U • S • DEPART!1ENT OF C0'1HERCE
`PATENT AND TRADEMARK OFFICE
`FEE RECORD
`
`100 MG 07/27!Y4 08276534
`
`1 201
`
`392.00 CK CHENG-101
`
`PT0-1556
`(5/87)
`
`4
`
`

`
`081276534
`. IN 1HE UNI1ED STATES PATENT AND TRADEMARK OFHCE
`
`Docket No. CHENG-101
`
`NEW APPLICATION TRANSMIITAL
`
`Commissioner of Patents and Trademarks
`Washington, DC 20231
`
`Sir:
`
`Enclosed are:
`
`(1) The papers required for a filing date under 37 CFR 1.53(b):
`(a) 33 pages of specification including 6 pages of claims with a total
`of 10 claims, with 4 independent and 6 dependent claims and (b) 14
`sheets of informal drawing together with one page of abstract.
`
`(2) Declaration.
`
`(3) Small Entity Statement.
`
`( 4) Express Mail Certificate.
`
`(5) A check in the amount of $392 payable to the Commissioner
`of Patents and Trademarks for the basic filing fee of $355 for a small
`entity plus $37 additional fee for 1 independent claims in excess of
`three independent claims at $3 7 per excess claim.
`
`Please address all correspondence and telephone calls to the
`undersigned.
`
`Dated: July 18, 1994 / .
`
`Enclosures
`
`Respectfully submitted,
`
`~~~ ~:::£__
`Alexander L. CR~-;--tJpplicant
`11 Springdale Avenue
`White Plains, N.Y. 10604
`914-428-0299
`
`5
`
`

`
`D~/276534
`
`, IN Tilli UNITED STATES PATENT AND TRADEMARK OFFICE
`
`Patent Application for
`
`DYNAMUCCHANNELMANAGEMENTAND
`SIGNALLING METHOD AND APPARATUS
`
`Docket: Cheng-1 01
`
`Express Mail Label Number: HB114345407 US
`
`Date of Deposit: July 18, 1994
`
`CERTIFICATE OF MAILING UNDER 37 CFR 1.10
`
`Honorable Commissioner of Patents and Trademarks
`Washington, D.C. 20231
`
`Sir:
`
`I hereby certify that the accompanying papers, namely:
`
`Patent Application, Small Entity Statement and $392 Check
`
`are being deposited with the United States Postal Service as "Express
`Mail Post Office to Addressee" service under 37 CFR 1.10 on the date
`indicated above addressed to:
`
`Commissioner of Patents and Trademarks
`Washington, D.C. 20231.
`
`Dated: July 18, 1994
`
`Enclosures
`
`Respectfully submitted,
`
`-~L-?'0_
`Alexander L. C~icant
`11 Springdale Avenue
`White Plains, N.Y. 10604
`914-428-0299
`
`6
`
`

`
`;ICI
`
`~~/276534
`
`APPLICATION FOR
`
`UNI1ED ST A 1ES P A 1ENT
`
`TO WHOM IT MAY CONCERN:
`
`Be it known that I, ALEXANDER L. CHENG, a citizen of the Republic of
`
`China (T-aiwan), residing at 11 Springdale Avenue, White Plains, New York
`
`10604, have invented new and useful improvements in a:
`
`DYNAMIC CHANNEL MANAGEMENT AND
`
`SIGNALLING METHOD AND APPARATUS
`
`of which the following is the specification.
`
`7
`
`

`
`081276534
`
`DYNAMITCCHANNELMANAGEMENTAND
`
`SIGNALLING METHOD AND APPARATUS
`
`Field of the Invention
`
`The present invention pertains generally to methods and apparatus for
`
`facilitating the two-way multi-media communication based on a shared
`
`transmission media such as coaxial cable-TV network, and more specifically
`
`to methods and apparatus for signalling channel management and protocol.
`
`Background of the Invention
`
`A multiple access communication system comprises a central controller,
`
`a shared transmission media and a plurality of remote terminals dispersed
`
`geographically. To provide the means for multiple access is a classical
`
`problem in communication systems with a shared common transmission
`
`media. Some of the well known schemes are frequency division multiple
`
`access or FDMA, time division multiple access or TDMA, and code division
`
`multiple access or CDMA.
`
`These multiple access schemes deal with the
`
`techniques of separating the communication bandwidth into traffic-bearing
`
`channels.
`
`In a FDMA scheme,
`
`the communication bandwidth is divided into
`
`the frequency bands. The TDMA scheme separates the communication
`
`bandwidth into time slots. The traffic is encoded and then decoded using
`
`different code in a CDMA scheme.
`
`In all these multiple access schemes the contention for access is
`
`resolved through signalling protocols on a pre-determined and fixed
`
`signalling channel. There are proposals to dynamically allocate traffic(cid:173)
`
`bearing channels to meet the service requirements in terms of lower blocking
`
`probability. However, in addition to availability, bandwidth and delay of the
`
`2 -
`
`8
`
`

`
`F
`
`traffic-bearing channel, the traffic requirements should include responsive(cid:173)
`
`ness of the signalling process and the quality of the transmission means.
`
`T?e signalling protocols for multiple access communication systems fall
`
`in two general categories for resolving the possible contention: scheduled
`
`access via polling or other means, and random access contention.
`
`In radio(cid:173)
`
`telephony and local-area-network (CSMA/CD) environment, the contention is
`
`resolved by monitoring the signal during transmission, which requires
`
`synchronization and/or means to monitor activities amongst all remote
`
`terminals and the central controller.
`
`In the CATV network, remote terminals
`
`have different distance from the central controller making synchronization
`
`difficult.
`
`It is also not feasible to detect collision, i.e., multiple remote
`
`terminals transmit at the same time, on the CATV network since the remote
`
`terminals are attached to different branches of the network. The poll and
`
`response method is often used to schedule the multiple access from plurality
`
`of remote terminals, but it has the disadvantage of inefficiency due to
`
`wasteful interaction with remote terminals that are not in need of servicing.
`
`Description Of The Related Art
`
`There are many proposals of means for dynamically adjusting the
`
`number of traffic-bearing channels according to varying traffic demands or
`
`the transmission quality in the radio telephony environment, e.g., U. S. Patent
`
`Nos. 5,134,709, 5,235,631 and 5,276,908.
`
`In addition U. S. Patent No.
`
`4,868,811 discusses the protocol over the common signalling channel for
`
`allocation of traffic-bearing channels. U. S. Patent No. 4,870,408 proposes a
`
`process of re-assigning subscriber units to balance the traffic load over the
`
`available channels. U. S. Patent No. 5,010,329 discloses a method for
`
`dynamically grouping terminals in blocks for which the central unit performs
`
`- 3 -
`
`9
`
`

`
`,..
`
`block polling on a common data channel. The present invention presents a
`
`method to dynamically allocate both signalling data and traffic-bearing
`
`channel~ and to dynamically assign remote terminals to
`
`these channels.
`
`The polling scheme is commonly used to resolve contention in a
`
`multiple access system. U. S. Patent No. 4,385,314 proposes a system to
`
`sequentiaHy poll all terminals.
`
`Due to the inherent inefficiency with
`
`sequential polling method, some proposals with the following variations for
`
`performance improvement have been presented. U. S. Patent No. 4,754,426
`
`proposes a two-level polling scheme with distributed control. U. S. Patent No.
`
`4,829,297 proposes use of a high priority group. U. S. Patent No. 4,868,816
`
`proposes a binary polling scheme, similar to the polling scheme in the present
`
`invention, with terminal address in each poll. U. S. Patent No. 4,924,461
`
`proposes a method to register other pending request on ·a second channel to
`
`interrupt sequential polling. U. S. Patent No. 4,942,572 proposes a dual rate
`
`polling method using pseudo random sequence at high rate to poll all
`
`terminals resulting possibly in contention with a small number of terminals,
`
`and following the high rate poll by specific poll at lower rate in case of
`
`collision. This invention differs from the prior art in that multiple access Is
`
`controlled through overlapping polling sequence executing on multiple
`
`channels in a parallel fashion. Only when collision occurs, this method will
`
`enter a selective polling sequence for contention resolution. The added
`
`benefit of this method is efficiency and redundancy against anomalies such as
`
`interference and component failure.
`
`Objects Of The Invention
`
`To overcome the problems mentioned above, the objective of the
`
`present invention is to present
`
`- 4 -
`
`10
`
`

`
`F
`
`A flexible and extensible method for signalling channel management;
`
`A flexible and extensible method for assigning remote terminals to the
`
`signalling channels;
`
`An efficient asynchronous signalling protocol.
`
`In the present invention, a dynamic process is disclosed to adjust the
`
`number of signalling channels to meet the requirements of varying traffic
`
`demand and the system growth. This is important in carrying multi-media
`
`traffic with different requirements in both the traffic-bearing channel
`
`bandwidth and the time required to setup a traffic-bearing channel. This
`
`dynamic signalling channel allocation and terminal assignment method also
`
`aids in system redundancy for anomalies such as interference and component
`
`failure.
`
`Integrated with the channel allocation and terminal assignment
`
`process, the present invention also presents an efficient controlled multiple
`
`access method. The central controller initiates the general polling on each
`
`signalling data channel in parallel to solicit request from all terminals
`
`assigned to the signalling data channel. Only when collision is detected, the
`
`central controller starts to poll selectively for resolution.
`
`Further objects and advantages of my invention will become apparent
`
`from considerations of the drawings and ensuing description thereof.
`
`Brief Summary of the Invention
`
`The multiple access communication system architecture depicted in
`
`Figure l comprises a plurality of remote terminals, a common shared
`
`transmission media, a central controller and interface to wide area networks.
`
`There are provided a number of communication channels (L) to the wide area
`
`networks, a number of communication channels (M) for supporting a plurality
`
`of remote terminals (N). The M number of channels to support
`
`- 5
`
`11
`
`

`
`F
`
`communication between the central controller and the remote terminals are
`
`separated into four categories as depicted in Figure 2, for carrying signalling
`
`data and user traffic in the forward and reverse directions, i.e., forward
`
`signalling data or FD channel, forward traffic bearer or FB channel, reverse
`
`signalling data or RD channel, and reverse traffic bearer or RB channel. All
`
`communication signals between the central controller and the remote
`
`terminals are multiplexed onto the shared transmission media.
`
`The remote terminals are equipment supporting the users'
`
`communication need and are distributed throughout the network.
`
`For
`
`simplicity reason, the summing device for signals from remote terminals are
`
`shown as a single device in Figure I. Each of the remote terminals has one RF
`
`data demodulator capable of receiving data on the assigned FD channel, one
`
`frequency agile receiver capable of tuning to· the assigned FB channel, one RF
`
`data modulator capable of transmitting data on the assigned RD channel, and
`
`one frequency agile transmitter capable of tuning to the assigned RB channel.
`
`The central controller comprises a switch and control mechanism, and a pool
`
`of transmitters and receivers for the communication channels. The central
`
`controller provides concentration and control function to meet the
`
`communication demand of the remote terminals much the same way as a
`
`Private Automated Branch eXchange or PABX. The central controller also
`
`translates the signalling information according to the requirement of the
`
`network. There are two levels of concentrations provided with this system:
`
`contention in the shared transmission media via the signalling protocol, and
`
`through the switching matrix of the central controller.
`
`The signalling channels are dynamically adjusted for efficiency and
`
`redundancy. This also adds to the extensibility of the system for the
`
`increasing traffic load and system growth. The downstream traffic on these
`
`r
`
`- 6 -
`
`12
`
`

`
`.......
`
`channels are scheduled by the central controller. Multiple access of the
`
`remote terminals for
`
`the upstream traffic are mitigated by separating remote
`
`terminals in groups via the channel allocation and the terminal assignment
`
`process. Prompted by the remote terminals at startup, or through the failure
`
`recovery procedure, or deemed necessary by the central controller, the
`
`channel allocation and terminal assignment process are initiated and
`
`controlled by the central controller. Through the registration process, the
`
`central controller assigns the remote terminal to a group supported by
`
`coupling of the specific forward and reverse signalling data channels.
`
`Afterwards, the communication between the central controller and the
`
`remote terminals follows a two-phase process. The controlled multiple access
`
`method is used, on each forward signalling data channel in parallel, for
`
`sporadic user data transfer or signalling purpose. The central controller
`
`either sends command to a specific remote terminal or solicits requests via a
`
`general poll from remote terminals assigned to the forward signalling data
`
`channel. The remote terminals respond to the controller's poll to request
`
`services. The selective polling process is used to identify the remote
`
`terminals involved in case of collision. The traffic bearer channel is used once
`
`the circuit is established via signalling protocol over the signalling data
`
`channels. The controlled multiple access scheme using overlapping polling
`
`method represents an efficient asynchronous signalling method and the
`
`decision process is designed to improve the effectiveness of the selective
`
`polling coverage during the contention resolution process.
`
`Accordingly the achieved benefits of the present invention are:
`
`General communication channels management architecture;
`
`• Flexible and extensible scheme for signalling channel management;
`
`7 -
`
`13
`
`

`
`Flexible and extensible scheme for assigning remote terminals to the
`
`signalling channels;
`
`Flexible and extensible scheme for supporting system growth and new
`
`services
`
`requirements;
`
`Improved system redundancy;
`
`Efficient asynchronous signalling protocol.
`
`Brief Description Of The Drawings
`
`Other objects, features and advantages of the invention will be apparent
`
`from the following Description of the Preferred Embodiment taken together
`
`with the accom/anying drawings in which:
`
`Figure 1 is a illustration of a multiple access communication system
`
`architecture with interconnections between the remote terminals,
`
`the central
`
`controller which comprises the switch and control module and a number of
`
`transmitters and receivers, and
`
`the wide-area network.
`
`Figure 2 /shows the channelization of the communication bandwidth of
`
`the shared transmission media between the central controller and the remote
`
`terminals for different functions.
`
`Figure 3 !depicts the possible mappings of forward and reverse
`
`signalling data channels.
`Figure 4f depicts the logic flow diagram for polling and registration
`process at the central controller.
`Figure sl depicts the logic flow diagram for command process at the
`central con troller.
`Figure 6 j is the logic flow diagram for registration, terminal
`
`reassignment, channel allocation, and terminal assignment process at the
`
`central controller.
`
`- 8 -
`
`14
`
`

`
`Figure 7 (fepicts the logic flow diagram for registration process at the
`
`remote
`
`terminals.
`
`Figure 8 8epicts the logic flow diagram for signalling process at the
`
`terminals.
`remote
`Figure 9 ~etails the message format for the signalling protocol between
`the central controller and
`the remote terminals.
`
`Figure lO /shows the ranges of remote terminals for selective polling
`
`during the contention resolution process.
`Figure 11 1 is a message exchange diagram for signalling protocol
`
`J
`
`between the central controller and the remote terminals illustrating a
`
`scenario of collision and its resolution.
`
`Figure 12/is the decision graph for contention resolution process using
`
`polling ranges as defined in Figure 10 using the regular polling method.
`
`Figure 13/ contains signalling message exchange diagrams for
`
`comparison of two methods using the regular and the overlapping polling
`
`cycle.
`
`Figure 14,· is the decision graph for contention resolution process using
`
`polling ranges as defined in Figure 10 using the overlapping polling method.
`l
`Figure 15 lis a message exchange diagram using the overlapping polling
`
`method for signalling protocol between the central controller and the remote
`
`terminals illustrating a scenario of collision and its resolution.
`
`Figure I 6 /is the system block diagram of the central controller for
`
`supporting
`
`telephone services.
`
`Figure 17 gis the system block diagram of a remote terminal for
`
`supporting
`
`telephone services.
`
`- 9 -
`
`15
`
`

`
`F
`
`A pool of communication channels 16 (L) are provided to the
`
`wide area networks 18, a pool of communication channels 20 (M) for
`
`supporting a plurality of remote terminals 14 (N). The M number of channels
`
`to support communication between the central controller 10 and the remote
`
`terminals 14 are separated into four categories for carrying signalling data
`
`and user traffic in the forward and reverse directions, i.e., forward signalling
`
`data or FD channel 22, forward traffic bearer or FB channel 24, reverse
`
`signalling data or RD channel 26, and reverse traffic bearer or RB channel 28.
`
`All communication signals between the central controller 10 and the remote
`
`terminals 14 are multiplexed onto the shared transmission media 12. All
`
`remote terminals 14 are equipment supporting the users' communication
`
`need and are distributed throughout the network. For simplicity reason, the
`
`summing device 30 for signals from remote terminals are shown as a single
`
`device in Figure 1.
`
`In a CATV network, this summing device 30 represents
`
`the splitters and taps connecting the branches that make up the network.
`
`The central controller 10 comprises a switch and control mechanism 32,
`
`and a pool of transmitters, called forward signalling data channel (FD) 22 and
`
`forward traffic bearer channel (FB) 24, and a pool of receivers, called reverse
`
`signalling data channel (RD) 26 and reverse traffic bearer channel (RB) 28.
`
`The central controller provides concentration and control function to meet the
`
`communication demand of the remote terminals much the same way as a
`
`Private Automated Branch eXchange or PABX. The central controller also
`
`translates the signalling information according to the requirement of the
`
`network.
`
`In addition to concentration provided through the switching matrix
`
`-- I o -
`
`16
`
`

`
`of the central controller, contention in the shared transmission media via the
`
`signalling protocol provides another level of concentration with this system.
`
`Each of the remote terminals has one radio frequency (RF) agile data
`
`demodulator capable of receiving on the assigned FD channel 34, one RF agile
`
`receiver tuned to the assigned FB channel 36, one RF agile data modulator
`
`capable of transmitting on the assigned RD channel 38, and one RF agile
`
`transmitter tuned to the assigned RB channel 40.
`
`Although the present invention is useful for interworking with a variety
`
`of different wide area networks, the telephone network will be used
`
`hereinafter to illustrate the present invention.
`
`As depicted in Figure 2, the bandwidth is channelized for carrying
`
`traffic in the forward and the reverse direction. Data channels are used for
`
`carrying signalling or data traffic while bearer channels are used for carrying
`
`user traffic similar to circuits in telephony.
`
`Therefore, there are altogether 4
`
`types of channels as depicted in Figure 2. FD-x is the signalling data channel
`
`in the forward direction 44, i.e., from the central controller to the remote
`
`terminals, numbered from 1 to a. FB-y is traffic bearer channel 46 in the
`
`forward direction numbered from l to b. RD-x' is signalling data channel 48
`
`in the reverse direction, i.e., from the remote terminals to the central
`
`controller, numbered from I to c. RB-y' is traffic bearer channel 50 in the
`
`reverse direction numbered from
`
`to d. A guard band 42 is also shown to
`
`separate the signals traveling in the forward and the reverse directions if
`
`they are to be put side-by-side. As explained later a and c should be greater
`
`than or equal to 2 for redundancy reason. Note that if the channels are of
`
`equal size, then a+b and c+d shall remain constant if all channels are available
`
`free of interference problem, i.e., there are a pool of channels from the central
`
`controller to the remote terminals, and a separate pool of channels from the
`
`-II-
`
`17
`
`

`
`F
`
`remote terminals to the central controller. These pools are set aside for a
`
`flexible allocation scheme to be described in detail later.
`
`Although it is not necessary to have all channel to have equal
`
`bandwidth, the communication process can be managed more easily if the
`
`channels have simplified structure with equal bandwidth.
`
`In case of equal
`
`size of the FD and FB channels, the management scheme can relocate the FD to
`
`a channel that is better suited for data transmission while FB channel
`
`carrying normal voice communication can tolerate a considerable more noisy
`
`channel than FD channel is able to. Similarly, the management process can
`
`take advantage of the flexibility afforded by the equal size of the RD and RB
`
`channels.
`
`If the bandwidth of the communication channels to the wide area
`
`network is equivalent to the channels of the shared transmission media, the
`
`number L is less than or equal to the number M, which in turn is less than or
`
`equal to the. number N.
`
`In case of channels with different sizes the central
`
`controller needs to have the additional intelligence for managing these
`
`channels efficiently, and to perform segmentation and reassembly. Note that
`
`communication with asymmetric bandwidth requirement such as multi-cast
`
`can be efficiently supported in this system.
`
`The FB-y and RB-y' channels are allocated according to the signalling
`
`protocol communicated over the FD-x and RD-x' channels. There is no
`
`contention in the forward direction, i.e., the traffic on each FD-x channel is
`
`scheduled independently. The number of signalling data channels are used to
`
`improve the efficiency servicing groups of remote terminals and the system
`
`redundancy.
`
`In case of transmission failure (detected through a number of
`
`retries without receiving acknowledgment), the central controller reverts
`
`back to FD-1 and then FD-2 for transmission to the specific remote terminal,
`
`while the remote terminals reverts back to RD-1 and then RD-2 for
`
`transmission and to FD-1 and FD-2 for reception. The FD-1 and FD-2 channels
`
`18
`
`

`
`p
`
`\
`
`are called primary forward signalling data channel and backup forward
`
`signalling data channel respectively. These RD-1 and RD-2 channels are called
`
`primary reverse signalling data channel and backup reverse signalling data
`
`channel respectively.
`
`With this general channelization architecture, a flexible management
`
`scheme is possible for channel arrangement and remote terminals grouping.
`
`For example, channel arrangement can be adjusted according to traffic
`
`pattern mix and/or more intelligent management scheme can be
`
`implemented with various priority lists. The channelization is shown to
`
`follow a FDMA scheme for ease of understanding, but this can also be easily
`
`adopted for TDMA or CDMA schemes.
`
`?
`
`Multiple access of the remote terminals for the upstream traffic are
`
`mitigated by separating remote terminals in groups via the channel allocation
`
`and the· terminal assignment process to be described later. The contention
`
`among remote terminals in each group is resolved through a controlled
`
`multiple access followed by selective polling in case of collision on each of the
`
`signalling data channel. The number of remote terminals assigned to each of
`
`the RD channel is to be evenly distributed according to the traffic demand.
`
`In
`
`the case of identical traffic requirements from all users, the number of
`
`remote terminals assigned to each of the RD channel will be equal.
`
`The mapping of forward and reverse signalling data channels is under
`
`the control of the central controller dynamically. The mapping of part (a) of
`
`Figure 3 depicts the simplest arrangement with each pair of forward and
`
`reverse signalling data channels forming a terminal group. For example, the
`
`terminal group receiving on FD-h channel will transmit on RD-k. The part (b)
`
`depicts the one-to-many mapping where the central controller transmits on
`
`one FD-n channel while the remote terminals belonging to the same group
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`respond in their assigned RD-o, RD-p, and RD-q channel respectively.
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`In part
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`19
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`\
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`~
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`(c) with the many-to-one mapping shows that the central controller transmits
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`on several FD (r, s and t) channels each reaching a subset of the group of the
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`remote terminals, which respond in the same RD-u channel. Depending on the
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`traffic pattern, some mapping will be more efficient in utilizing the
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`bandwidth, e.g., the many-to-one mapping as depicted in part (b) of Figure 3
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`is suitable for case where the traffic coming from the remote terminals far
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`exceeds the traffic in the forward direction. Note that the mapping of part (c)
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`can cause collision from remote terminals in different sub-sets of the same
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`terminal group. This is the only mapping that will require the contention
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`resolution process, described later, to be coordinated between multiple
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`signalling data channels. Different types of mapping can be used at the same
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`time (but not combined) for different segments of remote terminals when
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`deemed appropriate by
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`the central controller.
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`Prompted by the remote terminals at startup, or through the failure
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`recovery procedure, or deemed necessary by
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`the central controller, the
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`channel allocation and terminal assignment process is initiated and controlled
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`by the central controller. Through the registration process, the central
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`controller assigns the remote terminal to a group corresponding to a specific
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`set of signalling data channels. Afterwards, the communication between the
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`central controller and the remote terminals follows a two-phase process. The
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`controlled multiple access procedure is used on each of the signalling data
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`channels in parallel, for sporadic user data transfer and for signalling
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`purposes. The controller sends command to the remote terminal in case of
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`request from the network while the remote terminals respond to the
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`controller's poll to request services.
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`If dedicated channel is required to meet
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`the user's need, the traffic bearer channel is established via signalling
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`protocol over the signalling data channels.
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`,-14.-
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`20
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`p
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`In Figure 4, the logic flow is shown for the central controller's
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`initialization process and polling cycle. The polling process is executed in
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`parallel for each of the FD-x in an independent fashion. After the system
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`initialization, the central controller clears the channel allocation and terminal
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`assignment lists and starts the polling cycle on FD-1 and FD-2.
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`If there is
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`required transmission to the remote terminal, such as a incoming call, the
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`central controller enters the command mode. Otherwise the central controller
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`solicits for request from remote terminals assigned to the FD channel via a
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`general poll.
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`If there is no response from any of the remote terminal, the
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`polling cycle repeats after a time-out period expires.
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`If there is response
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`from remote terminals without collision or transmission error, the central
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`controller processes the request accordingly.
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`In case of collision or
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`transmission error, the central controller enters a selective polling cycle to
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`identify the remote terminal(s) involved in the collision or caused the
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`transmission error.
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`As depicted in Figure 5, the central controller in the command mode
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`sends the message destined for a specific remote terminal. Normally only the
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`addressed remote terminal will respond to
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`the command, therefore, there is
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`normally no need for collision processing except for transmission error.
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`If the
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`expected response is not received at the central controller from the addressed
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`terminal after the time-out period expires, the central controller assumes that
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`either FD-x or RD-x' channel is not usable by the addressed remote terminal.
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`In this case, the central controller retries for a number of times, then
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`proceeds with the terminal failure processing if there is still no response from
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`the specific remote terminal. The terminal failure processing removes the
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`failed remote terminal from the group and signals to the wide area network
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`that connection is not possible.
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`-I r;-
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`21
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`,.
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`\
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`))
`\
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`In Figure 6, the logic flow diagram for the registration, channel
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`allocation, terminal assignment and reassignment process is depicted. Upon
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`receiving a registration message on RD-1 or RD-2, the central controller
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`checks if the remote terminal is a newly registering terminal.
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`If the remote
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`terminal is a newly registering terminal and is authorized, the central
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`controller proceeds to check for available signalling data channels for the
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`remote terminal.
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`If the new remote terminal has not been authorized, the
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`central controller will deny the remote terminal from entering the network
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`by issuing a terminal disable command.
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`If the remote terminal has been
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`registered previously, the registration process is caused by channel failure
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`recovery procedure sensed at the remote terminal, and the central controller
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`will register the channel status and proceed to check for available signalling
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`data channels for the remote terminal. At any time, the central controller can
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`initiate the terminal re-assignment process if deemed appropriate for the
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`varying traffic demand or other system dynamics.
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`The determining factors of signalling data channels availability include
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`the number of remote terminals using the signalling data channel, the traffic
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`requirements, past collision count, channel error status, and bandwidth of the
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`signalling data channel. These factors will be calculated for each of the
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`existing signalling data channels in consideration of the specific group
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`mapping as depicted in Figure 3.
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`If there are signalling data channels in the
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`forward and the reverse direction, the registering remote terminal will be
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`assigned to the group.
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`If there is no available signalling data channel already
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`in use, the central controller will check for available channel from the pool of
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`transmitters and/or the poll of receivers, and proceeds with allocation if there
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`is available channel from the pool (or a pair in case that neither the forward
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`nor the reverse signalling data channels are available).
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`If the signalling data
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`channel is available, the central controller will complete the registration
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`-)b-
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`22
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`

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`process by commanding the remote terminal to tune to the assigned channels.
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`Otherwise, the central controller will deny the remote t