The present disclosure relates generally to wireless communications, and more particularly to digital video broadcast idle mode operation in wireless communication devices, for example, in cellular telephone handsets, corresponding devices and methods.
The Digital Video Broadcast Handheld system (DVB-H) is a low-power derivative of the DVB Terrestrial transmission standard (DVB-T) standard that was developed to bring broadcast services available on a transport stream to wireless communication devices. In DVB-H, power consumption is reduced by implementing time-slicing, wherein the wireless communication device is active approximately 10-20% of the time.
In the DVB-H specification, the network sends several DVB-H signaling tables to DVB-H enabled wireless communication devices. The Program Association Table (PAT) and the Program Map Table (PMT) in DVB-H are based on the MPEG2 specification. The PAT and PMT are transmitted by the network every 100 ms. The PAT lists all programs available on the current transport stream and the corresponding Program Mapping Table (PMT) Packet Identifier (PID). The PAT is generally updated each time a program is modified. The Network Information Table (NIT) and IP/MAC Notification Table (INT) are DVB-H specific must be transmitted at least every 30 seconds. The INT provides, among other information, the IP addresses of the available services.
The DVB-T specification applies to devices such as set-top boxes for which power consumption is not a substantial concern. A DVB-T device thus listens to all Program Association Tables and when a change is detected in a PAT, all associated tables are read and the updated data are stored in the set-top box or other device. Updating the tables every time the Program Association Table (PAT) changes, provides the user with near immediate access to programs.
One essential function of the DVB-H stack in a DVB-H enabled wireless communication device is to identify the physical channel packet identifier (PID) and IP address for services and programs. In idle mode, the DVB-H engine is not activated but may be turned on and so needs to maintain synchronization with the signaling tables. In idle mode, a DVB-H enabled wireless communication device reads the Program Association Table (PAT) every 2 seconds and reads the IP/MAC Notification Table (INT) only when the PAT is updated. Thus when the PAT is updated, the DVB-H enabled wireless communication device may not read the INT for several seconds. For these and other reasons, there could be unacceptable latency between the time a user requests a DVB program and the availability of the program.
The various aspects, features and advantages of the disclosure will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Detailed Description thereof with the accompanying drawings described below. The drawings may have been simplified for clarity and are not necessarily drawn to scale.
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In one embodiment, the content broadcast network infrastructure entity provides advance notice in a PAT when a future or subsequent PAT will be updated. The Program Association Table (PAT) is generated by an entity within the content broadcast network infrastructure entity. In one embodiment, a first program association table scheduled for transmission at a first time includes information about a future or subsequent program association table that has been modified relative to the first program association table, wherein the other program association table is scheduled for transmission at a time later than the time for which the first program association table is scheduled for transmission. In
In one embodiment, for example, the “next_modified_pat” descriptor indicates the time between the current PAT transmission and the next modified PAT emission. The unit is proposed to be the period between 2 successive PAT tables. The new descriptor, next_modified_pat, allows knowing in how many tables the next change will occur. This compressed distribution such as 1, 2, 4, 8 etc. . . . is coded on 16 bits. As the PAT tables are transmitted with regular period, the receiver knows in how many seconds it will receive the next modified table.
Upon receiving information indicating when a future program association table (PAT) that has been modified relative to the current PAT will be transmitted, a wireless device in idle mode may wake-up to receive only program association tables that have been modified. Accordingly, the wireless device operating in idle mode need not wakeup to listen to program association tables that do not contain any new information. The wireless communication device may thus save power that would otherwise be expended reading program association tables that have not been modified.
The device 400 also includes a two-way radio transceiver 460, for example, a 3GPP Universal Mobile Telecommunications System (UMTS) or a 3GPP2 or some other radio transceiver, though it need not necessarily be a cellular radio. The device may also include other transmitter and/or receivers, for example, Bluetooth, WLAN, infrared devices either alone or in combination with a cellular transceiver. In some embodiments, the DVB program association table (PAT) is received by the radio receiver. The exemplary device 400 also includes a satellite positioning system (SPS) receiver 470, for example, a NAVSTAR GPS receiver or a Galileo receiver or a GLONASS receiver. In other embodiments, however, the device does not include a transceiver other than the DVB receiver.
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While the present disclosure and the best modes thereof have been described in a manner establishing possession by the inventors and enabling those of ordinary skill in the art to make and use the same, it will be understood and appreciated that there are equivalents to the exemplary embodiments disclosed herein and that modifications and variations may be made thereto without departing from the scope and spirit of the inventions, which are to be limited not by the exemplary embodiments but by the appended claims.
Number | Date | Country | Kind |
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06300046.7 | Jan 2006 | EP | regional |