UNITED STATES PROVISIONAL PATENT APPLICATION
`
`For
`
`SWITCHED BROADCAST IMPLEMENTATION
`
`Inventor:
`
`Swaminatha V. Vasudevan, Fremont, California
`DavePritesh
`Kumar Dhandapani
`Biren Sood, Los Gatos, California
`Michael Taylor
`Zeev Vax, Tel-Aviv,Israel
`Nery Strassma, Ramat Gan,Israel
`Ran Oz, Modiin,Israel
`
`Prepared by:
`
`BLAKELY SOKOLOFF TAYLOR & ZAFMAN LLP
`12400 Wilshire Boulevard
`Los Angeles, CA 90025-1026
`(408) 947-8200
`
`Attorney's Docket No.: 5079P039Z
`
`EV521438731US
`“Express Mail” mailing label number:
`
`Date of Deposit:
`_March 16, 2005
`I herebycertify that I am causing this paperor 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 Commissionerfor Patents,
`Washington, D. C. 20231
`Patricia A. Balero
`d or printed nameof person mailing paper or fee)
`
`of person mailing paperor fee)
`
`SONY - Ex.-1006
`Sony Corporation - Petitioner
`
`SONY - Ex.-1006
`Sony Corporation - Petitioner
`
`1
`
`

`

`SWITCHED BROADCAST IMPLEMENTATION
`
`[0001]
`Switched Broadcast (SwB)is a new concept accepted enthusiastically,
`especially by the cable television operators. Essentially, it offers broadcast programs on
`demandonly. This way, precious bandwidth is saved. See, e.g., US patent application
`
`number: 09/841579, entitled METHOD AND SYSTEM FOR PROVIDING MULTIPLE
`
`SERVICES TO END-USERS, filed April 23, 2001, assigned to the assignee of the present
`
`invention and incorporated herein by reference.
`
`[0002]
`
`In order for this scheme to work, an SwBclientis installed in the home
`
`viewer’s set-top box (STB). Today’s STBs have known channels and methods to
`
`communicate with the operators’ head-ends. These communicationlines are used to convey
`
`to the head-end information regarding the channel a viewer wants to watch, and to convey to
`
`the STB, technical parameters of the desired program (such as frequency, program number,
`
`etc.). These communication lines have limited bandwidth. Therefore there is a need to reduce
`
`the amountoftraffic on them. Another problem is that viewers sometimes switch off their
`
`television sets but leave the STB on. This way, the head-end does not know that a viewer has
`
`stopped watching the desired program. The present invention provides methods to overcome
`
`these and other problems.
`
`[0003]
`
`In order to reduce communication between the multitude of STBs and the head-
`
`end, the head-end periodically send to the STB a list of currently available programs and
`
`their parameters. Occasionally, the head-end also sends update messagesofthis table. This
`
`way,if the program is available, the STB doesn’t need to request it specifically from the
`
`head-end.
`
`[0004]
`
`Programs may sometimes moveto a “regular” broadcast mode based on
`
`automatic policy based mechanisms. This can happen only on individual service groups. At
`
`different times, these programscan return to be switched broadcast programs.
`
`[0005]
`
`Viewer behavior is modeled constantly. This way, the system can decide thatit
`
`is highly likely that a program being broadcastis actually not viewed by anyone.It can
`
`removethis program and free bandwidth for other programs. In order to eliminate mistakes,
`
`viewers who are watching these programs mayreceive a warningprior to the removal ofthe
`
`program.If none of them respond within a certain period, the program will be removed
`
`[0006]
`
`In order to reduce tuning times, more popular programs may be broadcast when
`
`there is available bandwidth even in nobody requested them. Eventually, if the popularity of
`
`these programs continues to increase, they may moveout of the SwB poolandinto the
`
`regular broadcast pool.
`
`Clients/BigBandNetworks/5079P039Z/ProvApplicationAsFiledP039Z
`
`2
`
`

`

`[0007]
`
`It is very important to avoid cases where viewers can watch incorrect content
`
`(such as adult content). This can be avoided by the SwB systemifit allocates to the different
`
`programs fixed and unique parameters such as program numbers and PIDs.
`
`[0008]
`
`Since most programsare encrypted, they cannot be RateShapedat the edge.
`
`However,there is no needto set to each programafixed constant bit rate. There may be
`
`some pre-defined encoding levels used.
`
`[0009]
`
`A Dynamic Channel Map (DCM) istransmitted to all Switched Broadcast
`
`clients. It enables the following
`
`o
`
`Switched Broadcast Clients can be aware of the programs being transmitted
`
`at any momentand can pre-tune to them in advanceofreceiving this tuning
`
`information from a Switched Broadcast Server. This reduces the overall
`
`channel change time and increases the performanceofthe system.
`
`© The Switched Broadcast Server can mark a flag in the DCM that indicates
`
`that a channelis subject to be removed. This can prompt a Switched
`
`Broadcastclient to take someaction to allow this action to occur, prevent this
`
`action to occur, or notify the user of this impending action to prompt a user
`
`response. This optimizesthe utilization of stream bandwidth.
`
`o A popular Switched Broadcast channel can be flagged as “‘static”. In this
`
`mode, the Switched Broadcast Client can rely on the DCM and need not send
`
`a channel request message to the Switched Broadcast Server. This allows out-
`
`of-band networktraffic to be minimized/optimized.
`
`[0010)
`
`Whena Switched Broadcast Channel Change messageissent, it includes
`
`diagnostic information from previous channel changetransactions. This information is useful
`
`to transmit and log on the Switched Broadcast Server for gathering intelligence about the
`
`overall health of the service.
`
`[0011]
`
`A Switched Broadcast System can employ the use of pre-encrypted content.
`
`This eliminates any dependencies on the incumbent headend management system for overall
`
`system operation.
`
`[0012]
`
`The Switched Broadcast Client-Server protocol features two message types —
`
`an “init” message that is sent only once, and a channel change messagethat is sent whenever
`
`a channel is requested. By movingstatic information to the init message, the size of the
`
`channel change message is minimized and out of band networkefficiency is thus optimized.
`
`[0013]
`
`Switched Broadcast clients periodically send a “keep alive” message to a
`
`Switched Broadcast Server. This allows the Switched Broadcast Serverto affirm the
`
`functional state of the system. It also allows a backup Switched Broadcast Server to ascertain
`
`Clients/BigBandNetworks/5079P039Z/ProvApplicationAsFiledP039Z
`
`3
`
`

`

`the system state after one time cycle of keep-alive messages has propagated through the
`
`system.
`
`[0014]
`
`A Switched Broadcast System shares streams with other subscribers watching
`
`the same program,though it is not necessary to do so.It is possible to construct a Switched
`
`Broadcast system whereevery client receives a private unicast stream, and the switchingis
`
`performed on an individualbasis at the hub. Such a system yields the following advantages:
`°
`
`In a unicast Switched Broadcast system, the frequency, Program number, and
`
`PID values for a Switched Broadcast client can remain constant. This
`
`accelerates tuning times because theclient does not need to change the tuning
`
`frequency or parse Program Map Tables to view a program.
`
`Tuning time can be further accelerated by adding intelligence at the headend.
`
`Multiple versions of a broadcast program can be created, staggered in time.
`
`When a Switched Broadcast program is selected, the staggered program that
`
`will produce the fastest decode time can be dynamically selected for
`
`downstream transmission.
`
`Tuningcan also befacilitated if a stream is transmitted to a client only at an I
`
`frame. Alternatively, just before transmitting to a client, the headend
`
`transcodes a P frame into an I frame, transmits that new frame and continues
`
`transmitting the original stream immediately after the original P frame. To
`
`help enhance the seamless experience, B frames may be replaced by black
`frames around the switch point.
`
`Clients/BigBandNetworks/5079P039Z/ProvApplicationAsFiledP039Z
`
`4
`
`