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`For
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`SWITCHED BROADCAST IMPLEMENTATION
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`Inventor:
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`Swaminatha V. Vasudevan, Fremont, California
`Dave Pritesh
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`Kumar Dhandapani
`Biren Sood, Los Gatos, California
`Michael Taylor
`Zeev Vax, Tel-Aviv, Israel
`Nery Strassma, Ramat Gan, Israel
`Ran Oz, Modiin, Israel
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`Prepared by:
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`BLAKELY SOKOLOFF TAYLOR & ZAFMAN LLP
`12400 Wilshire Boulevard
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`Los Angeles, CA 90025-1026
`(408) 947-8200
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`Attorney's Docket No.: 5079P039Z
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`EV52143873 1 US
`“Express Mail” mailing label number:
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`Date of Deposit: March 16 2005
`I hereby certify that I am causing this paper or fee to be deposited with the United States
`Postal Service “Express Mail Post Office to Addressee” service on the date indicated above
`and that this paper or fee has been addressed to the Assistant Commissioner for Patents,
`Washington, D. C. 2023]
`Patricia A. Balero
`
`d r printed name of person mailing paper or fee)
`of person mailing paper or fee)
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`SONY - Ex.-1006
`Sony Corporation - Petitioner
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`1
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`SONY - Ex.-1006
`Sony Corporation - Petitioner
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`1
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`SWITCHED BROADCAST IMPLEMENTATION
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`[0001]
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`Switched Broadcast (SwB) is a new concept accepted enthusiastically,
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`especially by the cable television operators. Essentially, it offers broadcast programs on
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`demand only. This way, precious bandwidth is saved. See, e. g., US patent application
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`number: 09/841579, entitled METHOD AND SYSTEM FOR PROVIDING MULTIPLE
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`SERVICES TO END-USERS, filed April 23, 2001, assigned to the assignee of the present
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`invention and incorporated herein by reference.
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`[0002]
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`In order for this scheme to work, an SwB client is installed in the home
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`viewer’s set-top box (STB). Today’s STBs have known channels and methods to
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`communicate with the operators’ head-ends. These communication lines are used to convey
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`to the head-end information regarding the channel a viewer wants to watch, and to convey to
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`the STB, technical parameters of the desired program (such as frequency, program number,
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`etc). These communication lines have limited bandwidth. Therefore there is a need to reduce
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`the amount of traffic on them. Another problem is that viewers sometimes switch off their
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`television sets but leave the STB on. This way, the head-end does not know that a viewer has
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`stopped watching the desired program. The present invention provides methods to overcome
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`these and other problems.
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`[0003]
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`In order to reduce communication between the multitude of STBs and the head-
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`end, the head-end periodically send to the STB a list of currently available programs and
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`their parameters. Occasionally, the head-end also sends update messages of this table. This
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`way, if the program is available, the STB doesn’t need to request it specifically from the
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`head-end.
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`[0004]
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`Programs may sometimes move to a “regular” broadcast mode based on
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`automatic policy based mechanisms. This can happen only on individual service groups. At
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`different times, these programs can return to be switched broadcast programs.
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`[0005]
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`Viewer behavior is modeled constantly. This way, the system can decide that it
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`is highly likely that a program being broadcast is actually not viewed by anyone. It can
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`remove this program and free bandwidth for other programs. In order to eliminate mistakes,
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`Viewers who are watching these programs may receive a warning prior to the removal of the
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`program. If none of them respond within a certain period, the program will be removed
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`[0006]
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`In order to reduce tuning times, more popular programs may be broadcast when
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`there is available bandwidth even in nobody requested them. Eventually, if the popularity of
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`these programs continues to increase, they may move out of the SwB pool and into the
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`regular broadcast pool.
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`Clients/BigBandNetworks/S 079P039Z/ProvApplicationAsFiledP03 9Z
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`2
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`[0007]
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`It is very important to avoid cases where viewers can watch incorrect content
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`(such as adult content). This can be avoided by the SwB system if it allocates to the different
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`programs fixed and unique parameters such as program numbers and PIDs.
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`[0008]
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`Since most programs are encrypted, they cannot be RateShaped at the edge.
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`However, there is no need to set to each program a fixed constant bit rate. There may be
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`some pre-defined encoding levels used.
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`[0009]
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`A Dynamic Channel Map (DCM) is transmitted to all Switched Broadcast
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`clients. It enables the following
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`o
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`Switched Broadcast Clients can be aware of the programs being transmitted
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`at any moment and can pre-tune to them in advance of receiving this tuning
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`information from a Switched Broadcast Server. This reduces the overall
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`channel change time and increases the performance of the system.
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`0 The Switched Broadcast Server can mark a flag in the DCM that indicates
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`that a channel is subject to be removed. This can prompt a Switched
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`Broadcast client to take some action to allow this action to occur, prevent this
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`action to occur, or notify the user of this impending action to prompt a user
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`response. This optimizes the utilization of stream bandwidth.
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`0 A popular Switched Broadcast channel can be flagged as “static”. In this
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`mode, the Switched Broadcast Client can rely on the DCM and need not send
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`a channel request message to the Switched Broadcast Server. This allows out-
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`of-band network traffic to be minimized/optimized.
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`[0010]
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`When a Switched Broadcast Channel Change message is sent, it includes
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`diagnostic information from previous channel change transactions. This information is useful
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`to transmit and log on the Switched Broadcast Server for gathering intelligence about the
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`overall health of the service.
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`[0011]
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`A Switched Broadcast System can employ the use of pre-encrypted content.
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`This eliminates any dependencies on the incumbent headend management system for overall
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`system operation.
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`[0012]
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`The Switched Broadcast Client-Server protocol features two message types —
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`an “init” message that is sent only once, and a channel change message that is sent whenever
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`a channel is requested. By moving static information to the init message, the size of the
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`channel change message is minimized and out of band network efficiency is thus optimized.
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`[0013]
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`Switched Broadcast clients periodically send a “keep alive” message to a
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`Switched Broadcast Server. This allows the Switched Broadcast Server to affirm the
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`functional state of the system. It also allows a backup Switched Broadcast Server to ascertain
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`Clients/BigBandNetworks/5079P039Z/ProvApplicationAsFiledP039Z
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`3
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`the system state after one time cycle of keep-alive messages has propagated through the
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`system.
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`[0014]
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`A Switched Broadcast System shares streams with other subscribers watching
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`the same program, though it is not necessary to do so. It is possible to construct a Switched
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`Broadcast system where every client receives a private unicast stream, and the switching is
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`performed on an individual basis at the hub. Such a system yields the following advantages:
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`0
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`In a unicast Switched Broadcast system, the frequency, Program number, and
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`PID values for a Switched Broadcast client can remain constant. This
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`accelerates timing times because the client does not need to change the tuning
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`frequency or parse Program Map Tables to view a program.
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`0 Tuning time can be further accelerated by adding intelligence at the headend.
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`Multiple versions of a broadcast program can be created, staggered in time.
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`When a Switched Broadcast program is selected, the staggered program that
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`will produce the fastest decode time can be dynamically selected for
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`downstream transmission.
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`0 Tuning can also be facilitated if a stream is transmitted to a client only at an I
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`frame. Alternatively, just before transmitting to a client, the headend
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`transcodes a P frame into an I frame, transmits that new frame and continues
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`transmitting the original stream immediately after the original P frame. To
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`help enhance the seamless experience, B frames may be replaced by black
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`frames around the sWitch point.
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`CIients/BigBandNetworks/5079P03 9Z/ProvAppIicationAsFiledP03 9Z
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`4
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