Methods and apparatus for RF channel switching in a multi-frequency network

Methods and apparatus for RF channel switching in a multi-frequency network. In an aspect, a method includes identifying a multiplex set that comprises one or more content flows, wherein the multiplex set is one of a vertical multiplex (VM) set and a unified multiplex (UM) set, generating an overhead message that associates one or more RF carrier frequencies with the one or more content flows, and transmitting the overhead message over the multi-frequency network. An apparatus includes input logic configured to receive an overhead message that associates one or more content flows with one or more RF carrier frequencies, and processing logic configured to detect a channel switch event that identifies a selected content flow, determine a selected RF carrier frequency associated with the selected content flow based on the overhead message, and switch to the selected RF carrier frequency to receive the selected content flow.

BACKGROUND

The present application relates generally to the operation of data networks, and more particularly, to methods and apparatus for RF channel switching in a multi-frequency network.

Data networks, such as wireless communication networks, have to trade off between services customized for a single terminal and services provided to a large number of terminals. For example, the distribution of multimedia content to a large number of resource limited portable devices (subscribers) is a complicated problem. Therefore, it is important for network operators, content retailers, and service providers to have a way to distribute content and/or other network services in a fast and efficient manner and in such a way as to increase bandwidth utilization and power efficiency.

A multi-frequency network (MFN) is a network in which multiple radio frequencies (RFs) (or RF channels) are used to transmit media content. One type of MFN is a horizontal multi-frequency network (HMFN) where a distribution waveform is transmitted over different RF channels in different local areas. The same or different content may be transmitted as part of distribution waveforms carried over different RF channels in such local areas. Another type of MFN is a vertical multi-frequency network (MFN) in which multiple radio frequency (RF) channels are used in a given local area to transmit independent distribution waveforms with an aim to increase the capacity of the network (in terms of the ability to deliver more content to a device/end user). An MFN deployment may also consist of VMFN in certain areas and HMFN in certain other areas.

A typical VMFN comprises multiple distribution waveforms each comprising one or more content flows that can be selected by a device user for viewing. Additionally, information is provided with each distribution waveform that allows a receiver to determine the characteristics (e.g., Transmission Mode, Reed-Solomon coding, etc) of individual flows being transmitted. This information may be contained in a separate control channel. Before a receiver can decode flows carried by a particular distribution waveform, it needs to know these characteristics, and hence, it needs to decode the control channel.

Therefore, given the VMFN case described above, it will be assumed that two independent distribution waveforms are available on different RF channels. A receiver switching from a first RF channel to a second RF channel to receive additional flows will therefore incur the delay of having to acquire the control channel on the second RF channel. Once it does so, it can decode the information it needs to start decoding the flows on the second RF channel. Unfortunately, the time it takes to switch to the second RF channel and acquire the control channel information may increase channel switching time as perceived by the device user, and therefore may result in an unsatisfactory user experience.

Additionally, since the control channel also carries dynamic information about whether or not a content flow is present and its RF channel location, a receiver interested in receiving a particular content flow needs to periodically monitor the control channels on all RF channels used by the network to determine the location (i.e., RF channel) of the desired content flow. However, monitoring all RF channels can have a negative impact on device operation by causing an interruption of flows currently being decoded or by causing the acquisition of a flow to be missed. Furthermore, even if a receiver attempts to monitor all RF channels there is no guarantee that the information it acquires from one RF channel won't become stale while the receiver is monitoring other RF channels.

Therefore, it would be desirable to have a system that operates to quickly and efficiently identify the RF channel associated with a particular content flow and thereby facilitate fast channel switching capabilities in a vertical multi-frequency network.

SUMMARY

In one or more aspects, a switching system, comprising methods and apparatus, operates to quickly and efficiently identify the RF channel associated with a particular content flow in a vertical multi-frequency network. In an aspect, the switching system aggregates flow information associated with flows carried by multiple RF channels in a local region. The aggregated information is processed to generate one or more overhead messages that are transmitted to devices in the local region over control channels associated with RF channels used in the region. A device receiving the overhead messages can determine the availability of a particular flow and its location with respect to the multiple RF channels that may be available. The overhead messages allow a device to quickly determine the RF location of a particular flow without having to receive and decode flow location information from each RF channel. As a result, the switching system facilitates fast RF channel switching to provide an enhanced user experience.

In an aspect, a method is provided for RF channel switching in a multi-frequency network. The method comprises identifying a multiplex set that comprises one or more content flows, wherein the multiplex set is one of a vertical multiplex (VM) set and a unified multiplex (UM) set, generating at least one overhead message associated with the multiplex set that associates one or more RF carrier frequencies with the one or more content flows, respectively, and transmitting the at least one overhead message over the multi-frequency network.

In an aspect, an apparatus is provided for RF channel switching in a multi-frequency network. The apparatus comprises a multiplex set generator configured to identify at least one multiplex set that comprises one or more content flows, wherein the multiplex set is one of a VM and a UM set. The apparatus also comprises messaging logic configured to generate at least one overhead message associated with the multiplex set that associates one or more RF carrier frequencies with the one or more content flows, respectively, and output logic configured to transmit the at least one overhead message over the multi-frequency network.

In an aspect, an apparatus is provided for RF channel switching in a multi-frequency network. The apparatus comprises means for identifying a multiplex set that comprises one or more content flows, wherein the multiplex set is one of a VM set and a UM set. The apparatus also comprises means for generating at least one overhead message associated with the multiplex set that associates one or more RF carrier frequencies with the one or more content flows, respectively, and means for transmitting the at least one overhead message over the multi-frequency network.

In an aspect, a computer program product is provided that comprises a machine-readable medium that embodies a first set of codes for causing a computer to identify at least one multiplex set that comprises one or more content flows, wherein the multiplex set is one of a VM set and a UM set, a second set of codes for causing the computer to generate at least one overhead message associated with the multiplex set that associates one or more RF carrier frequencies with the one or more content flows, respectively, and a third set of codes for causing the computer to transmit the at least one overhead message over the multi-frequency network.

In an aspect, at least one integrated circuit is provided that is configured to provide RF channel switching in a multi-frequency network. The at least one integrated circuit comprises a first module for identifying at least one multiplex set that comprises one or more content flows, wherein the multiplex set is one of a VM set and a UM set, a second module for generating at least one overhead message associated with the multiplex set that associates one or more RF carrier frequencies with the one or more content flows, respectively, and a third module for transmitting the at least one overhead message over the multi-frequency network.

In an aspect, a method is provided for RF channel switching in a multi-frequency network. The method comprises receiving at least one overhead message that associates one or more content flows with one or more RF carrier frequencies, respectively, detecting a channel switch event that identifies a selected content flow, determining a selected RF carrier frequency associated with the selected content flow based on the at least one overhead message, and switching to the selected RF carrier frequency to receive the selected content flow.

In an aspect, an apparatus is provided for RF channel switching in a multi-frequency network. The apparatus comprises input logic configured to receive at least one overhead message that associates one or more content flows with one or more RF carrier frequencies, respectively. The apparatus also comprises processing logic configured to detect a channel switch event that identifies a selected content flow, determine a selected RF carrier frequency associated with the selected content flow based on the at least one overhead message, and switch to the selected RF carrier frequency to receive the selected content flow.

In an aspect, an apparatus is provided for RF channel switching in a multi-frequency network. The apparatus comprises input logic configured to receive at least one overhead message that associates one or more content flows with one or more RF carrier frequencies, respectively, and processing logic configured to detect a channel switch event that identifies a selected content flow, determine a selected RF carrier frequency associated with the selected content flow based on the at least one overhead message, and switch to the selected RF carrier frequency to receive the selected content flow.

In an aspect, an apparatus is provided for RF channel switching in a multi-frequency network. The apparatus comprises means for receiving at least one overhead message that associates one or more content flows with one or more RF carrier frequencies, respectively, means for detecting a channel switch event that identifies a selected content flow, means for determining a selected RF carrier frequency associated with the selected content flow based on the at least one overhead message, and means for switching to the selected RF carrier frequency to receive the selected content flow.

In an aspect, a computer program product is provided for RF channel switching in a multi-frequency network. The computer program product comprises a machine-readable medium embodying a first set of codes for causing a computer to receive at least one overhead message that associates one or more content flows with one or more RF carrier frequencies, respectively, a second set of codes for causing the computer to detect a channel switch event that identifies a selected content flow, a third set of codes for causing the computer to determine a selected RF carrier frequency associated with the selected content flow based on the at least one overhead message, and a fourth set of codes for causing the computer to switch to the selected RF carrier frequency to receive the selected content flow.

In an aspect, at least one integrated circuit is provided that is configured to provide RF channel switching in a multi-frequency network. The at least one integrated circuit comprises a first module for receiving at least one overhead message that associates one or more content flows with one or more RF carrier frequencies, respectively, a second module for detecting a channel switch event that identifies a selected content flow, a third module for determining a selected RF carrier frequency associated with the selected content flow based on the at least one overhead message, and a fourth module for switching to the selected RF carrier frequency to receive the selected content flow.

Other aspects will become apparent after review of the hereinafter set forth Brief Description of the Drawings, Description, and the Claims.

DESCRIPTION

In one or more aspects, a switching system is provided for fast channel switching in a multi-frequency network. In an aspect, the switching system aggregates flow information associated with content flows that are designated for distribution over wide and local regions using multiple RF channels. The aggregated information and the associated flows are then transmitted for distribution over each designated region. A device receiving the aggregated information can determine whether a particular flow is available and its associated RF channel in the VMFN. With this information, the device is able to perform fast channel switching because the device does not have to receive and decode separate flow location information for each RF channel that may be available in the VMFN. The system is well suited for use in wireless network environments, but may be used in any type of network environment, including but not limited to, communication networks, public networks, such as the Internet, private networks, such as virtual private networks (VPN), local area networks, wide area networks, long haul networks, or any other type of data network.

DEFINITIONS

The following definitions are used herein to describe aspects of a switching system.1. Local Area—Refers to a local geographic area such as a building, group of buildings, community, city, county or other local region in which services may be broadcast.2. Wide Area—Refers to a wide geographic area such as a county, state, multiple states, country, multiple countries or other wide region in which services may be broadcast.3. Multiplex/Content Multiplex—Refers to a grouping of content flows.4. Wide Area Multiplex—Refers to a grouping of content flows that are broadcasted over at least one wide area.5. Local Area Multiplex—Refers to grouping of content flows that are broadcasted over at least one local area.6. Wide Area Operations Infrastructure (WOI)—Refers to a grouping of transmitters and associated systems that operate to transmit content flows over a wide area. A WOI maps to the smallest geographical wide area which can carry a wide area multiplex. A wide area multiplex may be broadcasted over one or more WOs.7. Local Area Operations Infrastructure (LOI)—Refers to a grouping of transmitters and associated systems that operate to transmit content flows over a local area. A LOI maps to the smallest geographical local area which can carry a local area multiplex. A local area multiplex may be broadcasted over one or more LOs.8. RF Channel—Refers to a channel that is used to convey a content distribution waveform over a selected LOI.9. Content Channel—Refers to a set of content flows within a particular distribution waveform. For example, a distribution waveform may comprise multiple content channels and each content channel may comprise one or more content flows.
Acronyms

The following acronyms are used herein to describe aspects of a switching system.

NOC—Network Operations Center

LOC—Local Operations Center

LOI—Local Operations Infrastructure

WOI—Wide Operations Infrastructure

FDM—Flow Description Message

RDM—RF Description Message

UFDM—Unified Flow Description Message

URDM—Unified RF Description Message

Introduction

FIG. 1shows a network diagram100that illustrates the distribution of content flows over two wide area regions. For example, WM1102is distributed over a first WOI104and a second WOI106. The first WOI104comprises three LOIs, shown at108,110, and112. The second WOI106also comprises three LOIs, shown at114,116, and118. WM2120is also distributed over the first WOI104and WM3122is distributed over the second WOI106. In addition, LM1124is distributed over LOIs108and110, LM2126is distributed over LOIs112and114, and LM3128is distributed over LOIs116and118. Furthermore, LM4130is distributed over LOI114and LOI116, and LM5132is distributed over LOI118. It will be assumed that each LOI shown inFIG. 1utilizes at least two RF channels to broadcast the described multiplexes over each associated local region.

FIG. 2shows a diagram200that illustrates the allocation of RF channels utilized by two LOIs illustrated inFIG. 1. For example, the RF channels utilized by LOIs108and110are shown in the diagram200. The LOI108utilizes a first channel (RF1) and a third channel (RF3). The LOI110utilizes a second channel (RF2) and a fourth channel (RF4).

Each of the RF channels carries one or more multiplexes that are used to convey selected content and/or services. For example, the RF1channel may convey WM1(102) and LM1(124) over the LOI108and the RF3channel may convey WM2(122) over the LOI108.

FIG. 3shows a multiplex distribution diagram300that illustrates the distribution of multiplexes over selected local areas in aspects of a switching system. For example, the diagram300illustrates the distribution of multiplexes over the network100shown inFIG. 1. In each local area there are two RF channels that carry wide and local area multiplexes. For example, in LOI1108, the two RF channels are RF1and RF3which carry wide area multiplexes (WM1and WM2), respectively, and local area multiplex (LM1). The multiplexes carried in each local area can be determined from the diagram300.

Multiplex Sets

In aspects of a switching system, unique combinations of content multiplexes are defined that form multiplex sets. All the flows belonging to content multiplexes in a multiplex set are associated with that multiplex set. One type of multiplex set is referred to as a vertical multiplex (VM) set. A VM set is defined as a unique combination of content multiplexes carried in a LOI. It is also possible for the same VM set to be carried in multiple LOIs or WOs. VM sets are defined for both the wide area multiplexes and local area multiplexes that are distributed over each local area of the network100. In an aspect, a local VM set comprises all local multiplexes distributed over a selected local region and a wide VM set comprises all wide multiplexes distributed over a selected wide region. For example, referring now toFIG. 3, with respect to the wide area (WOI1) a wide VM set is shown at302, and with respect to the local area (LOI5) a local VM set is shown at304. As illustrated inFIG. 3, unique wide VM sets for all the wide areas are defined as follows.
VMSW1={WM1,WM2}
VMSW2={WM1,WM3}

As further illustrated inFIG. 3, unique local VM sets for all the local areas are defined as follows.
VMSL1={LM1}
VMSL2={LM2}
VMSL3={LM2,LM4}
VMSL4={LM3,LM4}
VMSL5={LM3,LM5}

In an aspect, another type of multiplexed set is defined that is referred to as a unified multiplex (UM) set. UM sets are formed by combining overlapping VM sets until overlapping is eliminated. The UM sets are defined separately for wide and local multiplexes. For example, with respect to the multiplexes illustrated inFIG. 3, a wide UM set is generated by combining the overlapping wide VM sets described above as follows.
UMSW1={WM1,WM2,WM3}

In an aspect, local UM sets are formed by combining the overlapping local VM sets as follows.
UMSL1={LM1}
UMSL2={LM2,LM3,LM4,LM5}
Implementation

FIG. 4shows a network400that comprises aspects of a switching system. For example, the network400may be part of the network100shown inFIG. 1. The network400comprises a network operations center (NOC)402, transmitter sites404and408, LOI406and devices432.

The NOC402operates to receive wide and local content multiplexes for distribution over selected wide and local areas of a multi-frequency network. For example, the NOC402operates to configure a multi-frequency network to distribute content. To accomplish this, the NOC402is aware of the geographic regions of the network, the RF channels used in each region, and any other network information that may be needed to distribute the wide and local content multiplexes.

In an aspect, the NOC402comprises aggregation logic410. The aggregation logic410operates to determine wide and local multiplex sets as described above. For example, wide and local VM sets are generated that identify unique combinations of wide and local multiplexes that are to be distributed to selected wide and local regions of the multi-frequency network400. The aggregation logic410operates to aggregate information about the wide and local multiplexes contained in the VM sets into one or more overhead messages. The overhead messages describe the flows in each multiplex and the RF channels that the flows of the multiplexes are to be distributed on. For example, the overhead messages are generated separately for wide and local multiplex sets. A more detailed description of the overhead messages generated by the aggregation logic410is provided in other sections of this document.

The NOC402operates to transmit the wide and local multiplexes and the generated overhead messages to the transmitter sites404and408. It should be noted that although only two transmitter sites are shown, the NOC402may transmit the multiplexes and associated overhead messages to any number of transmitter sites over any number of local and/or wide geographic regions.

In an aspect, the NOC402operates to transmit the multiplexes and the overhead messages to the transmitter sites404and408using any suitable transport mechanism, as illustrated at412. For example, in an aspect, the NOC402transmits the multiplexes and the overhead messages to the transmitter sites using an MPEG-2 transport mechanism. In this configuration, the multiplexes and overhead messages are assigned MPEG-2 transport identifiers so that each transmitter site can detect and receive appropriate multiplexes and overhead messages.

In an aspect, servers414and416at the transmitter sites404and408, respectively, use the transport identifiers to determine which multiplexes and overhead messages are intended for them to transmit over the LOI406. The servers414and416then operate to pack their respective multiplexes and overhead messages into transmission frames418and420, respectively, for transmission over the LOI406. The servers414and416utilize any suitable physical layer process to pack the multiplexes and overhead messages into the transmission frames418and420for transmission. By using the transport identifiers to determine the multiplexes and overhead messages intended for transmission over the LOI406, the servers414and416need not decode any of the multiplexes or overhead messages. The servers414and416need only detect the appropriate transport identifiers and then pack the received multiplexes and overhead messages into the transmission frames according to the physical layer process.

The transmission frames comprise the flows associated with the wide and local multiplexes and overhead messages generated by the aggregation logic410. In an aspect, the transmission frames comprise wide and local partitions that are used to convey the wide and local content flows, respectively. In addition, the wide and local partitions comprise wide and local control channels. The wide and local control channels are used to convey selected overhead messages generated by the aggregation logic410.

In an aspect, the transmitter site404operates to transmit its transmission frames418over the LOI406using a first RF channel422and the transmitter site408operates to transmit its transmission frames420over the LOI406using a second RF channel426. It should be noted that the two sites404,408may or may not be co-located and that, although time synchronized, different transmission frames are transmitted on each RF channel. Using multiple RF channels allows more content flows to be transmitted over the LOI406. The transmission frames418and420each comprises content flows from selected wide and local multiplexes as determined by the operation of the NOC402. In addition, the transmission frames418and420each comprise wide and local control channels to convey selected overhead messages to the devices432.

In another aspect, a local area operations center (LOC)430that is constructed similarly to the NOC402may be optionally used. In this aspect, the NOC402operates to provide wide area multiplexes and associated overhead messages to the transmitter sites, and the LOC430operates to provide local area multiplexes and associated overhead messages to the transmitter sites. In any of the described configurations, the transmitter sites404and408are able to determine which wide and local multiplexes and associated overhead messages they are to distribute over the LOI406in their respective transmission frames.

At the devices432, a device434comprises a receiver436that operates to tune to a selected RF channel to receive selected transmission frames. For example, the receiver436operates to tune to the RF channel422to receive the transmission frames418. The receiver436may also be tuned to receive the transmission frames420on the RF channel426. Regardless of the RF channel the receiver436is tuned to, the transmission frames that are received comprise wide and local control channels that convey the overhead messages generated by the aggregation logic410.

The receiver436passes the overhead messages to flow selection logic438that operates to decode the overhead messages to produce information about the availability and RF channel location of all flows transmitted on the RF channels within the LOI406. For example, the received overhead messages provide information about the flows associated with all wide and local content multiplexes being transmitted on all available RF channels within the LOI406.

The flow selection logic438operates to receive channel switch events. The channel switch events are events that cause the device434to switch from one RF channel to another RF channel to receive a different content flow. It should be noted that an RF channel switch refers to a switch between different RF channels received by a device, and that a content channel switch refers to a switch between content channels received at the device. A content channel switch will result in an RF channel switch if the desired content channel is carried on a different RF. An RF channel switch can also be initiated by a program on the device attempting to acquire content on a different RF. For the purposes of this description, a channel switch event is an event which causes an RF channel switch at a device.

In an aspect, a channel switch event may comprise a device user request or a request generated by a program executing at the device434. Because the RF channel location of all the flows in the LOI406are known to the device434based on the received overhead messages, the device434is able to quickly switch to the requested RF channel in response to the channel switch event. Because the device434received the overhead messages on its current RF channel, it does not have to decode each control channel on every available RF channel to determine what content flows are available. Thus, the system operates to facilitate fast content flow location and RF channel switching functions.

Therefore, aspects of the switching system operate to allow a device to quickly determine the availability of a selected flow and the RF channel location of flows in a LOI to facilitate fast channel switching in a multi-frequency network. It should be noted that the network400illustrates just one implementation of a switching system and that other implementations are possible within the scope of the various aspects.

FIG. 5shows a diagram of a transmission frame500for use in aspects of a switching system. For example, the transmission frame500may be packed with wide and local content multiplexes and overhead messages, and transmitted by the transmitter sites404and408shown inFIG. 4.

The transmission frame500comprises four sub-frames, shown generally at502, that are used to convey wide and local content. For example, each sub-frame502comprises a wide area partition504that is packed with wide area content, and a local area partition506that is packed with local area content.

Included in the wide area partition504is a wide area control channel508. The wide area control channel508operates to convey overhead messages pertaining to wide area content multiplexes. Included in the local area partition506is a local area control channel510. The local area control channel510operates to convey overhead messages pertaining to local area content multiplexes.

At the start of the transmission frame500are overhead information symbols (OIS)512that provide overhead information that is used to locate the wide area control channel, the local area control channel, and the wide and local content flows that are packed into the sub-frames502.

FIG. 6shows an example of aggregation logic600for use in aspects of a switching system. For example, the aggregation logic600is suitable for use as the aggregation logic410shown inFIG. 4. The aggregation logic600comprises messaging logic602, multiplex set generator604, multiplex input logic606, and output logic608all coupled to a data bus610.

The multiplex input logic606comprises at least one of a CPU, processor, gate array, hardware logic, memory elements, and/or hardware executing software. The multiplex input logic606operates to receive one or more wide and/or local area multiplexes612that are to be distributed over wide and local regions of a multi-frequency distribution network.

The multiplex set generator604comprises at least one of a CPU, processor, gate array, hardware logic, memory elements, and/or hardware executing software. The multiplex set generator604operates to generate one or more wide and local VM sets based on the intended distribution of the wide and local multiplexes612received by the multiplex input logic606. In an aspect, the multiplex set generator604operates to generate one or more UM sets based on the generated wide and local VM sets. For example, the multiplex set generator604operates to generate the VM and UM sets as described above with reference toFIG. 3.

The messaging logic602comprises at least one of a CPU, processor, gate array, hardware logic, memory elements, and/or hardware executing software. The messaging logic602operates to generate overhead messages for use in aspects of the switching system. In an aspect, the messaging logic602generates flow description messages (FDM) and RF description messages (RDM) that describe the availability and RF channel location of content flows contained in the VM sets generated by the multiplex set generator604. In another aspect, the messaging logic602operates to generate unified flow description messages (UFDM) and unified RF description messages (URDM) that describe the availability and RF channel location of content flows contained in the UM sets generated by the multiplex set generator604. For example, a URDM messages provides RF channel identifiers for all LOIs associated with a particular UM set. A more detailed description of the FDM, UFDM, RDM, and URDM messages is provided in other sections of this document.

The output logic608comprises at least one of a CPU, processor, gate array, hardware logic, memory elements, and/or hardware executing software. The output logic608operates to output content multiplexes (i.e., multiplex sets) and overhead messages for distribution to LOIs in a multi-frequency network.

In an aspect, the switching system comprises a computer program product comprising one or more program instructions (“instructions”) or sets of “codes” stored or embodied on a machine-readable medium, which when executed by at least one processor, for instance, a processor at the aggregation logic600, provides the functions described herein. For example, the sets of codes may be loaded into the aggregation logic600from a machine-readable medium, such as a floppy disk, CDROM, memory card, FLASH memory device, RAM, ROM, or any other type of machine-readable medium that interfaces to the aggregation logic600. In another aspect, the sets of codes may be downloaded into the aggregation logic600from an external device or network resource. The sets of codes, when executed, provide aspects of a switching system as described herein.

FIG. 7shows a diagram that illustrates an example of an RF description message700for use in aspects of a switching system. For example, the RDM700is generated by the messaging logic602shown inFIG. 6.

In an aspect, the RDM700is generated separately for each LOI and is configured to associate an RF channel identifier702with an RF carrier frequency704utilized within a selected LOI to convey selected multiplexes. Thus, in a LOI that utilizes two RF carrier frequencies, the RDM will have two entries that associate RF channel identifiers702with two RF carrier frequencies704. In an aspect, the RDM can be generated for more than one LOI as well.

FIG. 8shows a diagram that illustrates an example of a flow description message800for use in aspects of a switching system. For example, the FDM800is generated by the messaging logic602shown inFIG. 6.

In an aspect, the FDM800is generated separately for each wide and local VM set and is configured to associate a flow identifier802with an RF channel identifier804. For example, in an aspect, the RF channel identifiers804are the RF channel identifiers702provided by the RDM700shown inFIG. 7. Thus, a separate FDM800is provided for each wide and local VM set and operates to identify the RF channels that convey content flows provided by wide and local VM sets.

Example

FIG. 9shows a diagram900that illustrates an example of overhead message generation and distribution for use in aspects of a switching system. For example, the diagram900illustrates how aspects of a switching system operate to distribute a wide VM set and a local VM set over a LOI908in a multi-frequency network. In an aspect, the overhead messages illustrated inFIG. 9are generated by the messaging logic602shown inFIG. 6.

For the purpose of this example, it will be assumed that the multi-frequency network utilizes two RF carrier frequencies (RF1, RF2) to broadcast wide and local VM sets to devices in the LOI908. The wide VM set comprises first and second wide multiplexes (WM1, WM2) where WM1comprises flows1,2and WM2comprises flows3,4. The local VM set comprises first and second local multiplexes (LM1, LM2) where LM1comprises flow5and LM2comprises flow6. It also will be assumed that the content multiplexes are packed into transmission frames for distribution within the LOI908. For example, a transmission frame910is packed with wide and local content and transmitted over the carrier frequency RF1. Additionally, a transmission frame912is packed with wide and local content and transmitted over the carrier frequency RF2. In an aspect, the transmission frames910and912are formatted as the transmission frame500shown inFIG. 5.

In an aspect, the aggregation logic600integrates information from the wide and local VM sets to generate a wide FDM message902, a local FDM message904, and an RDM message906. The wide FDM message902associates flows1-4of the wide VM set with the RF channel identifiers (0, 1). The wide FDM message902is distributed over the LOI908in a wide control channel914that is provided in a wide area partition916of transmission frame910and a wide area partition918of the transmission frame912.

In an aspect, the local FDM message904associates flows5-6with RF channel identifiers (0, 1). The local FDM message904is distributed over the LOI908in a local control channel920that is provided in a local area partition922of transmission frame910and a local area partition924of the transmission frame912.

The RDM message906associates the RF channel identifiers (0, 1) with the RF carrier frequencies (RF1, RF2), respectively, that are used in the LOI908. In an aspect, the RDM message906is distributed over the LOI908in the local control channel920that is part of the transmission frames910and912. However, it should be noted that the RDM message906can be distributed over the LOI908in the wide control channel914. By cross-referencing information in the RDM906with information in the FDMs (902,904), the RDM message906allows a receiving device to determine which RF carrier frequency is being used in the LOI908to transmit a particular wide or local content flow.

In an aspect, a URDM message, which is discussed in another section of this document, associates RF channel identifiers with the RF carrier frequencies used in multiple LOs. However, it should also be noted that when RDM messages are generated on a per LOI basis, the NOC402may operate to assign RF channel identifiers such that RF carrier frequencies carrying the same wide content multiplexes in a VM set are assigned the same RF channel identifier to optimize the size of the FDM messages for increased efficiency.

Thus, the switching system operates to integrate information pertaining to wide and local VM sets into overhead messages that are distributed over a LOI in wide and local control channels. Because the integrated information is received by devices tuned to any RF channel in the LOI908, every device is able to receive and decode the overhead messages to determine the availability and RF channel location of any flow distributed in the LOI908. Thus, the switching system operates to facilitate fast RF channel location and RF channel switching since devices do not have to decode information on multiple RF frequencies to determine the availability and location of content flows conveyed within the LOI908.

FIG. 10shows an example method1000for operating aggregation logic for use in aspects of a switching system. For clarity, the method1000is described herein with reference to the aggregation logic600shown inFIG. 6. For example, in an aspect, a processor executes one or more sets of codes to control the aggregation logic600to perform the functions described below. In another aspect, at least one integrated circuit is provided that comprises one or more modules configured to perform the functions described below.

At block1002, one or more wide and/or local multiplexes are received for distribution over a multi-frequency network. For example, the multiplexes are received at the multiplex input logic606shown inFIG. 6.

At block1004, the distribution of the received multiplexes is determined. For example, the NOC402determines the distribution of the wide and local multiplexes to selected WOIs and LOs. In an aspect, the NOC402determines which multiplexes are to be delivered to each LOI and the RF carrier frequencies that are to be used to deliver the content flows of each multiplex within each LOI.

At block1006, wide and local multiplex sets are determined. For example, for each LOI in the distribution network, wide and local VM sets are determined. In an aspect, UM sets are also determined. In an aspect, the multiplex set generator604operates to determine the wide and local VM and/or UM sets. For example, the VM and UM sets are determined as described with reference toFIG. 3.

At block1008, wide and local FDM and/or UFDM overhead messages are generated. For example, information from the VM sets is integrated into the wide and local FDM messages, which are formatted as shown inFIG. 8. A similar process is performed on the UM sets to generate the UFDM messages. In an aspect, the messaging logic602operates to generate the wide and local FDM and/or UFDM overhead messages.

At block1010, RDM and/or URDM overhead messages are generated. For example, the RDM messages are formatted as shown inFIG. 7. In an aspect, the messaging logic602operates to generate the RDM and/or URDM overhead messages. A description of URDM messages is provided in another section.

At block1012, the overhead messages and multiplexes in the multiplex sets are output to transmitter sites for transmission in a multi-frequency network. In an aspect, the output logic614operates to output the overhead messages and content flows of the multiplex sets to the transmitter sites. For example, the overhead messages and content flows are transmitted to the transmitter sites using an MPEG-2 transport mechanism.

Thus, the method1000operates to provide an aspect of a switching system. It should be noted that the method1000represents just one implementation and that other implementations are possible within the scope of the aspects.

FIG. 11shows an example of flow selection logic1100for use in aspects of a switching system. For example, the flow selection logic1100is suitable for use as the flow selection logic438shown inFIG. 4. The flow selection logic1100comprises processing logic1102, overhead message decoder1104, and control channel input logic1106all coupled to a data bus1108.

The control channel input logic1106comprises at least one of a CPU, processor, gate array, hardware logic, memory elements, and/or hardware executing software. The control channel input logic1106operates to obtain wide and local control channel data that is received over the RF channel the device is currently tuned to and passes this data to the overhead message decoder1104. For example, the wide and local control channel data is received from wide and local control channels that are part of a received transmission frame as illustrated inFIG. 5.

The overhead message decoder1104comprises at least one of a CPU, processor, gate array, hardware logic, memory elements, and/or hardware executing software. In an aspect, the overhead message decoder1104operates to decode overhead messages in the received wide and local control channel data. For example, the overhead message decoder1104decodes wide FDM, local FDM, wide and local UFDM, RDM and URDM messages that are received in the wide and local control channel data. The overhead message decoder1104operates to decode the wide FDM, local FDM, wide and local UFDM, RDM and URDM messages and cross-references the information in the messages to determine the availability and RF channel location of content flows within the current LOI of the device. For example, a wide FDM message that is formatted as illustrated inFIG. 9is decoded to determine the RF channel identifiers associated with wide area content flows within the current LOI. A local FDM message that is formatted as shown inFIG. 9is decoded to determine the RF channel identifiers associated with local area content flows within the current LOI. An RDM message that is formatted as illustrated inFIG. 9is decoded to determine a mapping between RF channel identifiers and the actual RF carrier frequencies being used within the current LOI. This information is passed to the processing logic1102.

The processing logic1102comprises at least one of a CPU, processor, gate array, hardware logic, memory elements, and/or hardware executing software. In an aspect, the processing logic1102operates to interface with a device user, an executing application program, or other logic from which an RF channel switch event is received. For example, a device user may request an RF channel switch to view a particular content flow which is carried on an RF different than the current RF. The processing logic1102responds to the request by generating a channel switch message that operates to cause the device to switch to a new RF channel to receive the desired content flow. For example, the channel switch message may be sent to a device transceiver. Because the processing logic1102has received the RF channel locations of all content flows in the LOI from the message decoder1104, the channel switch message comprises the RF carrier frequency and identity of the desired flow. With this information, a device can quickly switch to the desired RF channel to receive the desired flow without having to receive and decode information from multiple RF channels to determine what content flows they contain. Thus, channel switch time is reduced which provides for an enhanced user experience.

In an aspect, the switching system comprises a computer program product comprising one or more program instructions (“instructions”) or sets of “codes” stored or embodied on a machine-readable medium, which when executed by at least one processor, for instance, a processor at the flow selection logic1100, provides the functions described herein. For example, the sets of codes may be loaded into the flow selection logic1100from a machine-readable medium, such as a floppy disk, CDROM, memory card, FLASH memory device, RAM, ROM, or any other type of machine-readable medium that interfaces to the flow selection logic1100. In another aspect, the sets of codes may be downloaded into the flow selection logic1100from an external device or network resource. The sets of codes, when executed, cause the flow selection logic1100to provide aspects of a switching system as described herein.

FIG. 12shows an example of a method1200for use at a device in aspects of a switching system. For clarity, the method1200is described herein with reference to the flow selection logic1100shown inFIG. 11. For example, in an aspect, the processing logic1102executes one or more sets of codes to control the flow selection logic1100to perform the functions described below.

At block1202, wide and local control channel data is received. In an aspect, the wide and local control channel data is received by the control channel input logic1106. For example, wide and local control channel data is received at a device in a sequence of transmission frames as illustrated inFIG. 5.

At block1204, wide and local FDM and/or UFDM messages are decoded. In an aspect, the wide and local FDM/UFDM messages are received as part of the control channel data. The wide and local FDM messages are formatted as illustrated inFIG. 8. The wide and local UFDM messages are formatted as illustrated inFIG. 13. The wide and local FDM/UFDM messages associate content flows with RF channel identifiers. In an aspect, the overhead message decoder1104operates to decode the wide and local FDM/UFDM messages. As a result, content flows provided by wide and local multiplexes over a LOI and associations between content flows and RF channel identifiers are determined.

At block1206, RDM/URDM messages are decoded. In an aspect, the RDM/URDM messages are received as part of the wide or local control channel data. The RDM message is formatted as illustrated inFIG. 7, and the URDM message is formatted as illustrated inFIG. 14. The RDM/URDM messages associate RF channel identifiers with RF carrier frequencies that are used to transmit content in a LOI (RDM) or in multiple LOIs (URDM). In an aspect, the overhead message decoder1104operates to decode the RDM/URDM messages. As a result, the RF carrier frequencies associated with RF channel identifiers are determined.

At block1208, a determination is made as to whether an RF channel switch event has been received. For example, an RF channel switch event may be received from a device user or from an executing program. In an aspect, the processing logic1102operates to determine if an RF channel switch event has been received and the identity of a desired content flow. If an RF channel switch event has been received, the method proceeds to block1210. If an RF channel switch event has not been received, the method ends at block1214.

At block1210, information from the FDM/UFDM and RDM/URDM is cross-referenced based on the identity of the desired content flow to determine its RF carrier frequency. Because the processing logic1102knows the RF channel locations of all content flows in the LOI, when a channel switch event is received, the processing logic1102cross-references the flow identifier provided in the channel switch event with information from the FDM/UFDM messages to determine an RF channel identifier. The processing logic1102then uses the information from the received RDM/URDM messages to cross-reference the channel identifier to determine an actual RF carrier frequency.

At block1212, a fast RF channel switch is performed in response to the received channel switch event. In an aspect, the processing logic1102operates to generate and output a channel switch message that provides a flow identifier and associated RF location (i.e. carrier frequency). The channel switch message causes the device to switch to a new RF channel to receive the desired content flow. With this information, a receiver (i.e., receiver438) at a device can quickly switch to the desired RF channel to receive the desired flow. Thus, channel switch time is minimized because it is not necessary to decode multiple RF carrier frequencies to determine the availability and location of the desired content flow.

Thus, the method1200operates to provide an aspect of a switching system. It should be noted that the method1200represents just one implementation and that other implementations are possible within the scope of the aspects.

Overhead Message Generation for UM Sets

In another aspect, overhead messages are generated based on the UM sets. In an aspect, the multiplex set generator604operates to generate UM sets and the messaging logic602operates to generate the overhead messages described below based on the UM sets. For example, referring again toFIG. 3and the discussion above, the following wide and local UM sets were determined.
UMSW1={WM1,WM2,WM3}
UMSL1={LM1}
UMSL2={LM2,LM3,LM4,LM5}

In an aspect, UFDM messages are generated based on these UM sets. For example, a wide UFDM message is generated that associates all the flows of UMSW1(i.e., flows in WM1, WM2, and WM3) with RF channel identifiers based on all the LOIs where WM1, WM2, WM3are to be distributed. Furthermore, a local UFDM message is generated that associates all the flows of UMSL1(i.e., the flows of LM1) with RF channel identifiers based on all the LOIs where LM1is to be distributed. Another UFDM messages is generated that associates all the flows of UMSL2(i.e., the flows of LM2, LM3, LM4, LM5) with RF channel identifiers based on all the LOIs where LM2, LM3, LM4, LM5are to be distributed.

In an aspect, the URDM messages are generated based on the UM sets and the LOIs where the UM sets are distributed. For example, an URDM message is generated and is transmitted in each LOI associated with a particular UM set. Thus, with respect to UMSL2, an URDM message is generated that associates the RF channel identifiers with RF carrier frequencies for all LOIs that distribute UMSL2. The same is true with respect to URDM messages generated for other UM sets.

As a result, the use of UFDM and URDM messages provides efficiency, reduced complexity, and cost savings. For example, by using UFDM messages it may not be necessary to generate an FDM message for each VM set. By using URDM messages it may not be necessary to generate an RDM message for each LOI. Thus, for example, the use of UFDM and URDM messages means that NOC logic and transmitter site logic may be simplified. For example, since network transmitters would not have to support filtering of specific control channel messages their complexity can be reduced.

Therefore, overhead messages may be generated based on any combination of VM sets and UM sets, and the determination of which technique is used may depend on the multi-frequency network deployment.

FIG. 13shows an example of a unified FDM message (UFDM)1300for use in aspects of a switching system. For example, the UFDM1300is generated by the messaging logic602shown inFIG. 6and illustrates a UFDM based on the UMSW1described above. For example, for the purpose of this example, it will be assumed that UMSW1comprises WM1(flows1,2), WM2(flows3,4), and WM3(flows5,6).

In an aspect, a UFDM message is generated separately for each wide and local UM set and is configured to associate a flow identifier1302with an RF channel identifier1304. In an aspect, a UFDM message is transmitted to all LOIs that are to distribute the underlying multiplex sets. For example, the UFDM1300is based on UMSW1described above and will be distributed (as part of the wide control channel) to all LOIs (i.e., LOI1-LOI6) as illustrated inFIG. 3because the underlying multiplexes (i.e., WM1-WM3) are distributed to those LOs. With regards to a UFDM generated from UMSL1, this UFDM would be distributed to LOI1and LOI2as illustrated inFIG. 3because these LOIs are to receive the underlying multiplex LM1. Furthermore, with regards to a UFDM generated from UMSL2, this UFDM would be distributed (as part of the local control channel) to LOI3thru LOI6as illustrated inFIG. 3because these LOIs are to receive the underlying multiplex LM2, LM3, LM4, LM5).

FIG. 14shows an example of a unified RDM message (URDM)1400for use in aspects of a switching system. For example, the URDM1400is generated by the messaging logic602shown inFIG. 6and illustrates a URDM based on the UMSW1described above. The URDM message can be generated for LOIs associated with wide or local UM sets and distributed as part of the wide or local control channel in all LOIs covering the associated UM set.

In an aspect, the URDM message1400is configured to associate an RF channel identifier1404with an RF frequency carrier1406for all LOIs1402for which the underlying UM set is to be distributed. For example, the URDM1400is based on UMSW1described above and will be distributed to all LOIs (i.e., LOI1-LOI6) as illustrated inFIG. 3because the underlying multiplexes (i.e., WM1-WM3) are distributed to those LOs.

In an aspect, the URDM1400is generated so that RF channel identifiers are assigned such that RF carrier frequencies that carry different multiplexes within a UM set are not assigned the same channel identifier. This is to ensure that a given content flow can be uniquely associated with a given RF center frequency when determining RF location for that flow.

FIG. 15shows an example of aggregation logic1500for use in aspects of a switching system. For example, the aggregation logic1500is suitable for use as the aggregation logic600shown inFIG. 6. In an aspect, the aggregation logic1500is implemented by at least one integrated circuit comprising one or more modules configured to provide aspects of a switching system as described herein.

The aggregation logic1500comprises a first module comprising means (1502) for identifying a multiplex set that comprises one or more content flows, wherein the multiplex set is one of a vertical multiplex (VM) set and a unified multiplex (UM) set. In an aspect, the means1502comprises the multiplex set generator604. The aggregation logic1500also comprises a second module comprising means (1504) for generating at least one overhead message associated with the multiplex set that associates one or more RF carrier frequencies with the one or more content flows, respectively. In an aspect, the means1504comprises the messaging logic602. The aggregation logic1500also comprises a third module comprising means (1506) for transmitting the at least one overhead message over the multi-frequency network. In an aspect, the means1506comprises the output logic608.

FIG. 16shows an example of flow selection logic1600for use in aspects of a switching system. For example, the flow selection logic1600is suitable for use as the flow selection logic1100shown inFIG. 11. In an aspect, the flow selection logic1600is implemented by at least one integrated circuit comprising one or more modules configured to provide aspects of a switching system as described herein.

The flow selection logic1600comprises a first module comprising means (1602) for receiving at least one overhead message that associates one or more content flows with one or more RF carrier frequencies, respectively. In an aspect, the means1602comprises the control channel input logic1106. The flow selection logic1600also comprises a second module comprising means (1604) for detecting a channel switch event that identifies a selected content flow. In an aspect, the means1604comprises the processing logic1102. The flow selection logic1600also comprises a third module comprising means (1606) for determining a selected RF carrier frequency associated with the selected content flow based on the at least one overhead message. In an aspect, the means1606comprises the processing logic1102. The flow selection logic1600also comprises a fourth module comprising means (1608) for switching to the selected RF carrier frequency to receive the selected content flow. In an aspect, the means1608comprises the processing logic1102.

The description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these aspects may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects, e.g., in an instant messaging service or any general wireless data communication applications, without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. The word “exemplary” is used exclusively herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects.

Accordingly, while aspects of a switching system have been illustrated and described herein, it will be appreciated that various changes can be made to the aspects without departing from their spirit or essential characteristics. Therefore, the disclosures and descriptions herein are intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.