Patent Application
20110072469
In mobile broadcast networks, such as next generation digital video broadcast network, a fringe area within a cell or spanning across multiple cells influence the quality of service to end users. When fringe areas, such as tunnels, indoor areas, secluded areas, etc., occur within a broadcast network, a receiver has no means to detect such fringe areas before entering one or being very close to the fringe areas. Hence, such a receiver does not attempt to choose another broadcast network.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
Aspects of the present disclosure relate to a system and method for signaling and determining one or more fringe areas within broadcast networks. Other aspects provide methods which utilize ellipses in signaling the fringe areas within a broadcast network to one or more receivers.
Certain embodiments are illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements and in which:
In the following description of the various embodiments, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention.
Although shown as a single network in
Devices 105-120 may be configured to interact with each other or other devices, such as content server 130 or service provider 125. In one example, mobile device 110 may include client software 165 that is configured to coordinate the transmission and reception of information to and from content provider/server 130. In one arrangement, client software 165 may include application or server specific protocols for requesting and receiving content from content server 130. For example, client software 165 may comprise a Web browser or mobile variants thereof and content provider/server 130 may comprise a web server. Billing services (not shown) may also be included to charge access or data fees for services rendered. In one arrangement where service provider 125 provides cellular network access, e.g. acts as a wireless service provider, client software 165 may include instructions for access and communication through the cellular network. Client software 165 may be stored in computer-readable memory 160 such as read only, random access memory, writeable and rewriteable media and removable media in device 110 and may include instructions that cause one or more components—e.g., processor 155, a transceiver, and a display—of device 110 to perform various functions and methods including those described herein.
Computer executable instructions and data used by processor 228 and other components of mobile device 212 may be stored in a storage facility such as memory 234. Memory 234 may comprise any type or combination of read only memory (ROM) modules or random access memory (RAM) modules, including both volatile and nonvolatile memory such as disks. Software 240 may be stored within memory 234 to provide instructions to processor 228 such that when the instructions are executed, processor 228, mobile device 212 and/or other components of mobile device 212 are caused to perform various functions or methods such as those described herein. Software may include both applications and operating system software, and may include code segments, instructions, applets, pre-compiled code, compiled code, computer programs, program modules, engines, program logic, and combinations thereof. Computer executable instructions and data may further be stored on computer readable media including electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, CD-ROM, DVD or other optical disk storage, magnetic cassettes, magnetic tape, magnetic storage and the like. Some or all of the instructions implemented by processor 228 or other components so as to carry out the operations described herein may also be stored as hard-wired instructions (e.g., logic gates). For example, processor 228 could include one or more application specific integrated circuits (ASICs) configured to carry out operations such as those described herein.
Mobile device 212 or its various components may be configured to transmit and/or receive, decode and process various types of transmissions including digital broadband broadcast transmissions that are based, for example, on one or more Digital Video Broadcast (DVB) standards, such as Digital Video Broadcast-Handheld (DVB-H), Digital Video Broadcast-Terrestrial (DVB-T), Digital Video Broadcast-Second Generation Terrestrial/Next Generation Handheld (DVB-T2/NGH), Digital Video Broadcast-Cable (DVB-C), Digital Video Broadcast-Second Generation Cable (DVB-C2), Digital Video Broadcast-Satellite (DVB-S), Digital Video Broadcast-Second Generation Satellite (DVB-S2) or Digital Video Broadcast-Multimedia Home Platform (DVB-MHP), through a specific broadcast transceiver 241. Other digital transmission formats may alternatively be used to deliver content and information regarding availability of supplemental services. Additionally or alternatively, mobile device 212 may be configured to receive, decode and process transmissions through FM/AM Radio transceiver 242, wireless local area network (WLAN) transceiver 243, and telecommunications transceiver 244. Transceivers 241, 242, 243 and 244 may, alternatively, include individual transmitter and receiver components. In one or more arrangements, mobile device 212 may further include a gyroscopic sensor (not shown) configured to determine an orientation of mobile device 212. According to one or more further aspects, mobile device 212 may include a GPS device for receiving and determining location information from one or more GPS satellites.
Although the above description of
According to one or more aspects, each of multiplexed streams 305a-305g is carried through different physical layer pipes (PLPs) of broadcast stream 307. A PLP, as used herein, generally refers to a channel providing allocated resources through which data for particular services or content may be transmitted in the physical layer (as defined in the Open Systems Interconnection (OSI) Reference Model). Each of multiplexed streams 305a-305g may include program specific information/service information (PSI/SI) defining the services provided. For example, the PSI/SI for stream 305a might indicate a service provider (e.g., a television broadcast provider) and a service type (e.g., FM radio, digital radio, digital television) for the content included therein. Additionally or alternatively, carrier stream 307 may include PSI/SI for services that are currently available or that will be available in the future.
Content servers 301a-301g may each include various components including a processor 309, random access memory (RAM) 311, read only memory (ROM) 313 and a database 315. Processor 309 may be configured to execute various instructions and to perform calculations for preparing and transmitting scalable video broadcasts. RAM 311 and ROM 313 may be configured to store instructions for execution or access by the processor 309. Database 315 may be used to store content, subscriber information, network information and the like.
In the illustrated example, the framing bit pattern is 1011. Thus, if the receiver knows that each frame in a transport stream is 32 bits long, the receiver will look for the bits 1, 0, 1 and 1 spaced 32 bits apart from the preceding bit and in that particular order. This allows the receiver to align itself so that it is able to time its reception of frames appropriately.
Pilot signals P1 and P2 are generally defined to enable fast channel searching and service discovery within a frame. In particular, pilot signal P1 may be used to enable a fast initial scan for signals and to signal Fast Fourier Transform (FFT)-size and frequency offsets to a receiver while pilot signal P2 may be used to define physical layer (L1) and frame specific information in addition to data link layer (L2) signaling. For example, L2 signaling may include program specific information/service information. Accordingly, by examining L1 pre-signaling section 415 and, in particular, ‘TYPE’ field 421, a receiver may recognize the types of broadcasts that are carried within stream 401 and determine whether to process those broadcasts. In some arrangements, the P1 and P2 signaling information may be defined for an entire superframe rather than a single frame (i.e., specifying types of broadcast transmissions across an entire superframe and not just the frame in which the P1 and P2 signaling information is carried).
Additionally, a receiver may identify the particular PLPs corresponding to each of the types of broadcasts carried in stream 401 using data specified in configurable portion 417 of L1 post-signaling section 419. As illustrated in
A fringe area is a coverage area within a broadcast network, for example in a cell or within a transmitter part of one cell, where a broadcast signal from a “default” system is not available. Such fringe areas may include buildings, tunnels, and secluded areas. Any number of different reasons may exist for why such a fringe area is present, including obstructions due to high levels of concrete and/or metal, electromechanical interference, electrical interference, and/or other reasons. Fringe areas may be permanent and/or may be intermittent. For example, a building or tunnel may be a permanent type of fringe area while a construction area may be an intermittent type of fringe area. For an intermittent type of fringe area, the fringe area may cease to exist. If a broadcast signal is not available, it is desired to have access to the same service or to any service by a different transmission system. Such different transmission systems may include, e.g., 3G networks, wireless local area network, LTE networks and/or any other suitable networks.
According to some exemplary embodiments, a receiver may be signaled of the existence of a fringe area.
The formula of the ellipse 900 is as follows,
where a, b ε(the set of all real numbers).
The geographical coordinates, i.e., longitude and latitude, may be given to the center of the ellipse. The ellipse may be rotated to any angle, i.e., 0-360°. Other generally elliptical shaped areas may be utilized in accordance with principles described herein. The mathematical description with respect to
Due to the odd shape of a fringe area, utilizing a single ellipse to be drawn over the entire fringe area may not be desired. Utilizing a single ellipse in some odd shaped fringe areas may have more area outside of the fringe area itself included within the ellipse than the actual fringe area. In accordance with at least one aspect of the present disclosure, a plurality of ellipses may be utilized with respect to a fringe area.
The signaling of a fringe area based on the described ellipse method may be accomplished by different combinations of the association of a fringe area with a cell, e.g., cell_id, and a transmitter identifier, e.g., Tx_id.
((x−xo)2/a2)+((y−y0)2/b2)=1
In mathematics, an ellipse may be defined in origo (x0=0 and y0=0) and so that half axises are parallel to x and y axis. Due to this definition, a rotation is utilized which determines how much the ellipse or coordinate is turned compared to “normal” coordinates.
The syntax and semantics for parameters within the fringe_area_descriptor may be described in the following:
Other representations of signaling may be used to specify a generally elliptical shape.
Proceeding to step 1305, the current estimated location of a receiver is detected in accordance with known methods, e.g., using GPS, and/or determining the location based on the received Tx_ids and cell_ids. In step 1307, the estimated location of the receiver related to the location of the indicated fringe area is determined. This determination may be done based on the information determined in step 1303, step 1305, the estimated direction of the receiver apparatus, and/or the estimated speed of the receiving apparatus.
Moving to step 1309, a determination is made as to whether a change of network is needed or should be desired. For example, this determination may be made due to the updated location information of the receiver indicating a likelihood of entering the fringe area within a predetermined period of time. If no change of network is needed, the process returns to step 1307. If the fringe area is approaching and the network change is needed to continue and/or to select alternative service for consumption, the method moves to step 1311. In step 1311, a list of potential available systems or communication networks providing such content is requested from the network. In step 1313, a desired network is selected from the list of potential available systems. Finally, the receiver performs roaming/handover into the selected network in step 1315. The handover may be performed without assistance from a transmitting, e.g., broadcast, network. In some embodiments it may be performed using two-way handoff protocols. Aspects of the method performed in
The process begins and at step 1401 at least one broadcast stream may be transmitted at a broadcast network. An example of a broadcast network may be a DVB-T2/NGH network. At step 1403, a determination is made as to whether at least one fringe area exists in the broadcast network. The at least one fringe area may be determined, for example, by means of measurement campaigns, where the signal quality information is measured, e.g., manually, within the assumed cell/transmitter coverage area and the signal coverage map is provided where the at least one fringe area may be roughly detected from the assumed cell/transmitter coverage area. This may be done during the installation phase of the network or during special tests measurements. In another aspect the receiving apparatus may act also as a tracking device where the receiving apparatus is tracking the availability of coverage and it reports it on demand or on voluntary basis to a provider. Such a determination in step 1403 may include utilizing at least one generally elliptically shaped area to indicate a location of the at least one fringe area. A generally elliptically shaped area may include information regarding a rotational angle of the shaped area for an indication of the orientation of the at least one fringe area. For example, if the fringe area is a building, the orientation of the generally elliptically shaped area may be more vertical in comparison to a fringe area correlating to a tunnel. In addition, such a determination may include utilizing a plurality of shaped areas for defining the at least one fringe area. Proceeding to step 1405, information of the at least one fringe area may be provided in at least one associated signaling section to the at least one broadcast stream. The associated signaling section may be in the L2 signaling, the L1 pre-signaling, and/or the L1 post signaling. In one example, the provided information in step 1405 may include a location of the at least one fringe area within the at least one broadcast network.
The indication of one or more fringe areas in a current cell by a transmitter via a broadcast signal to at least one receiver is described. Such information may be used to approve the handover and to enable a constant good quality of service by executing a seamless handover in advance, e.g., before fringe area is nearby, the fringe area is reached, the signal is below a threshold, and/or a signal loss occurs. One example may be a notification about a tunnel within a service area. The signaling may be done in L2 signaling, L1 pre-signaling, and/or L1 post signaling. Then, based on GPS data of the receiver or based on the information received in broadcast stream like for example cell ID or transmitter ID, handover to a network that provides the desired service like for example a 3G, WLAN or LTE network may be implemented prior to the receiver entering the fringe area.
It should be understood that any of the method steps, procedures or functions described herein may be implemented using one or more processors in combination with executable instructions stored in memory that cause the processors and other components to perform the method steps, procedures or functions. As used herein, the terms “processor” and “computer” whether used alone or in combination with executable instructions stored in a memory or other computer-readable storage medium should be understood to encompass any of various types of well-known computing structures including but not limited to one or more microprocessors, special-purpose computer chips, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), controllers, application-specific integrated circuits (ASICs), combinations of hardware/firmware/software, or other special or general-purpose processing circuitry.
The methods and features recited herein may further be implemented through any number of computer readable media that are able to store computer readable instructions. Examples of computer readable media that may be used include RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, DVD or other optical disk storage, magnetic cassettes, magnetic tape, magnetic storage and the like.
Additionally or alternatively, in at least some embodiments, the methods and features recited herein may be implemented through one or more integrated circuits (ICs). An integrated circuit may, for example, be a microprocessor that accesses programming instructions or other data stored in a read only memory (ROM). In some such embodiments, the ROM stores programming instructions that cause the IC to perform operations according to one or more of the methods described herein. In at least some other embodiments, one or more the methods described herein are hardwired into an IC. In other words, the IC is in such cases an application specific integrated circuit (ASIC) having gates and other logic dedicated to the calculations and other operations described herein. In still other embodiments, the IC may perform some operations based on execution of programming instructions read from ROM or RAM, with other operations hardwired into gates and other logic of IC. Further, the IC may output image data to a display buffer.
Although specific examples of carrying out the subject matter have been described, those skilled in the art will appreciate that there are numerous variations and permutations of the above-described systems and methods that are contained within the spirit and scope of the invention as set forth in the appended claims. Additionally, numerous other embodiments, modifications and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure.
