Commercial Mobile Alert System (CMAS) in Release-9

I have blogged about Public Warning System and covered CMAS as part of that earlier.

The following is an extract from 3G Americas white paper, "3GPP Mobile Broadband Innovation Path to 4G: Release 9, Release 10 and Beyond: HSPA+, SAE/LTE and LTE-Advanced,":

In response to the Warning, Alert, and Response Network (WARN) Act passed by Congress in 2006, the Federal Communications Commission (FCC) established the Commercial Mobile Alert Service (CMAS) to allow wireless service providers who choose to participate, to send emergency alerts as text messages to their users who have CMAS capable handsets.

The FCC established a Commercial Mobile Service Alert Advisory Committee (CMSAAC) for the development of a set of recommendations for the support of CMAS. The CMSAAC recommendations were included as the CMAS Architecture and Requirements document in the FCC Notice of Proposed Rule Making (NPRM) which was issued in December 2007. In 2008, the FCC issued three separate Report and Order documents detailing rules (47 Code of Federal Regulations [CFR] Part 10) for CMAS. The FCC CMAS First Report and Order specifies the rules and architecture for CMAS. The FCC CMAS Second Report and Order establishes CMAS testing requirements and describes the optional capability for Noncommercial Educational (NCE) and public broadcast television stations distribute geo-targeted CMAS alerts. The FCC CMAS Third Report and Order defined the CMAS timeline, subscriber notification requirements for CMSPs, procedures for CMSP participation elections and the rules for subscriber opt-out. The FCC also issued a CMAS Reconsideration and Erratum document.

The CMAS network will allow the Federal Emergency Management Agency (FEMA), to accept and aggregate alerts from the President of the United States, the National Weather Service (NWS), and state and local emergency operations centers, and then send the alerts over a secure interface to participating commercial mobile service providers (CMSPs). These participating CMSPs will then distribute the alerts to their users. between the issuance of the second and third Report & Order documents.

As defined in the FCC CMAS Third Report and Order, CMSPs that voluntarily choose to participate in CMAS must begin an 18 month period of development, testing and deployment of the CMAS no later than 10 months from the date that the Government Interface Design specifications available. On December 7, 2009, the CMAS timeline of the FCC CMAS Third Report and Order was initiated with the announcement by FEMA and the FCC that the Joint ATIS/TIA CMAS Federal Alert GW to CMSP GW Interface Specification (J-STD-101) has been adopted as the Government Interface Design specification referenced in the FCC CMAS Third Report and Order.

Participating CMSPs must be able to target alerts to individual counties and ensure that alerts reach customers roaming outside a provider’s service area. Participating CMSPs must also transmit alerts with a dedicated vibration cadence and audio attention signal. Emergency alerts will not interrupt calls in progress. CMAS supports only English text-based alert messages with a maximum displayable message size of 90 English characters.

For purposes of CMAS, emergency alerts will be classified in one of three categories:

1. Presidential Alerts. Any alert message issued by the President for local, regional, or national emergencies and are the highest priority CMAS alert

2. Imminent Threat Alerts. Notification of emergency conditions, such as hurricanes or tornadoes, where there is an imminent threat to life or property and some immediate responsive action should be taken

3. Child Abduction Emergency/AMBER Alerts. Alerts related to missing or endangered children due to an abduction or runaway situation

The subscribers of participating CMSPs may opt out of receiving Imminent Threat and Child Abduction/AMBER alerts, but cannot opt out from Presidential Alerts.

The following figure shows the CMAS Reference Architecture as defined in the FCC CMAS First Report and Order:


Reference Point C is the secure interface between the Federal Alert GW and the Commercial Mobile Service Provider (CMSP) GW. The Reference Point C interface supports delivery of new, updated or canceled wireless alert messages, and supports periodic testing of the interface. This interface is defined in the J-STD-101, the Joint ATIS/TIA CMAS Federal Alert GW to CMSP GW Interface Specification.

Federal Government entity (i.e. FEMA) responsible for the administration of the Federal Alert GW. FEMA will perform the function of aggregating all state, local, and federal alerts and will provide one logical interface to each CMSP who elects to support CMAS alerts.

For GSM and UMTS systems, wireless alert messages that are received by CMSP GWs will be transmitted to targeted coverage areas using GSM-UMTS Cell Broadcast Service (CBS). The CMAS functionality does not require modifications to the 3GPP-defined Cell Broadcast Service.

The ATIS WTSC-G3GSN Subcommittee is developing the CMAS via GSM-UMTS Cell Broadcast Service Specification. The purpose of this standard is to describe the use of the GSM-UMTS Cell Broadcast Service for the broadcast of CMAS messages. The standard includes the mapping of CMAS application level messages to the Cell Broadcast Service message structure.

The ATIS WTSC-G3GSN Subcommittee is developing the Cell Broadcast Entity (CBE) to Cell Broadcast Center (CBC) Interface Specification. The purpose of this standard is to define a standard XML based interface to the Cell Broadcast Center (CBC). The CMSP Alert GW will utilize this interface to provide the CMAS Alert message information to the CBC for broadcast via CBS.

The ATIS WTSC-G3GSN Subcommittee has developed the Implementation Guidelines and Best Practices for GSM/UMTS Cell Broadcast Service Specification and this specification was approved in October 2009. The purpose of this specification is to describe implementation guidelines and best practices related to GSM/UMTS Cell Broadcast Service regardless of the application using CBS. This specification is not intended to describe an end-to-end Cell Broadcast architecture, but includes clarifications to the existing 3GPP CBS standards as well as “best practices” for implementation of the 3GPP standards. CMAS is an example of an application that uses CBS.

J-STD-100, Joint ATIS/TIA CMAS Mobile Device Behavior Specification, defines the common set of requirements for GSM, UMTS, and CDMA based mobile devices behavior whenever a CMAS alert message is received and processed. A common set of requirements will allow for a consistent user experience regardless of the associated wireless technology of the mobile device. Additionally, this common set of requirements will allow the various local, state, and Federal level government agencies to develop subscriber CMAS educational information that is independent of the wireless technology.

CMAS VIA LTE/EPS

In order to comply with FCC requirements for CMAS, CMSPs have a need for standards development to support CMAS over LTE/EPS as it relates to the network-user interface generally described as the “E-Interface” in the CMAS Reference Architecture. The intent of ATIS WTSC-G3GSN is to build upon LTE text broadcast capabilities currently being specified by 3GPP for the Public Warning System (PWS).

3GPP STANDARDS

3GPP TS 22.268. Public Warning System (PWS) Requirements, covers the core requirements for the PWS and covers additional subsystem requirements for the Earthquake and Tsunami Warning System (ETWS) and for CMAS. TS 22.268 specifies general requirements for the broadcast of Warning Notifications to broadcast to a Notification Area that is based on the geographical information as specified by the Warning Notification Provider. This specification also defines specific CMAS requirements based on the three Reports & Orders issued to date by the FCC.

3GPP TS 23.401. GPRS enhancements for E-UTRAN access, specifies the Warning System Architecture for 3GPP accesses and the reference point between the Cell Broadcast Center (CBC) and Mobility Management Entity (MME) for warning message delivery and control functions. This TS identifies the MME functions for warning message transfer (including selection of appropriate eNodeB), and provides Stage 2 information flows for warning message delivery and warning message cancel. The architecture and warning message delivery and control functions support CMAS.

3GPP TS 29.168. Cell Broadcast Center interfaces with the EPC – Stage 3, specifies the procedures and application protocol between the Cell Broadcast center and the MME for Warning Message Transmission, including the messages, information elements and procedures needed to support CMAS.

3GPP TS 36.300. E-UTRA and E-UTRAN – Overall description – Stage 2, specifies the signaling procedures for the transfer of warning messages from the MME to the eNodeB. The signaling procedures support CMAS operations.

3GPP TS 36.331. E-UTRA Radio Resource Control (RRC) – Protocol specification, specifies the radio resource control protocol for UE-to-E-UTRAN radio interface and describes CMAS notification and warning message transfer.

3GPP TS 36.413. E-UTRAN – S1 Application Protocol (S1AP), specifies the E-UTRAN radio network layer signaling protocol between the MME and eNodeB, and describes the warning message transfer needed for CMAS.

3GPP participants are working to complete these specifications and other UE procedures for supporting PWS and CMAS.

ATIS WTSC-G3GSN will develop a Standard for a CMAS via LTE Broadcast Capability Specification. This Standard will map the CMAS application level messages to the LTE warning message transfer protocol (i.e. for CMAS).

This ATIS WTSC-G3GSN effort has an anticipated completion date of December 31, 2010. This takes into account the time needed for completion of the ongoing 3GPP standards development on warning message broadcast for LTE.

ATIS WTSC G3GSN and TIA TR45.8 Subcommittees in conjunction with FEMA will also be jointly developing a testing certification specification for the Reference Point C interface between the Federal Alert GW and the CMSP GW based upon the requirements defined in J-STD-101. This specification has an anticipated completion date of December 31, 2010.

ETWS detailed in LTE and UMTS

Its been couple of years since the introductory post on 3GPP Earthquake and Tsunami Warning service (ETWS). The following is more detailed post on ETWS from the NTT Docomo technical journal.

3GPP Release 8 accepted the standard technical specification for warning message distribution platform such as Area Mail, which adopts pioneering technology for faster distribution, in order to fulfil the requirements concerning the distribution of emergency information e.g. earthquakes, tsunamis and so on in LTE/EPC. The standard specifies the delivery of emergency information in two levels. The Primary Notification contains the minimum, most urgently required information such as “An earthquake occurred”; the Secondary Notification includes supplementary information not contained in the Primary Notification, such as seismic intensity, epicentre, and so on. This separation allows implementation of excellent information distribution platforms that can achieve the theoretically fastest speed of the warning distribution.

The purpose of the ETWS is to broadcast emergency information such as earthquake warnings provided by a local or national governments to many mobile terminals as quickly as possible by making use of the characteristic of the widespread mobile communication networks.

The ETWS, in the same way as Area Mail, detects the initial slight tremor of an earthquake, the Primary Wave (P wave - The first tremor of an earthquake to arrive at a location), and sends a warning message that an earthquake is about to happen to the mobile terminals in the affected area. ETWS can deliver the first notification to mobile terminals in the shortest theoretical time possible in a mobile communication system (about four seconds after receiving the emergency information from the local or national government), which is specified as a requirement by 3GPP.

The biggest difference between Area Mail and the ETWS is the disaster notification method (Figure 1). Earthquake warnings in Area Mail have a fixed-length message configuration that notifies of an earthquake. ETWS, on the other hand, achieves distribution of the highest priority information in the shortest time by separating out the minimum information that is needed with the most urgency, such as “Earthquake about to happen,” for the fastest possible distribution as a Primary Notification; other supplementary information (seismic intensity, epicentre, etc.) is then distributed in a Secondary Notification. This distinction thus implements a flexible information distribution platform that prioritizes information distribution according to urgency.

The Primary Notification contains only simple patterned disaster information, such as “Earthquake.” When a mobile terminal receives a Primary Notification, it produces a pre-set alert sound and displays pre-determined text on the screen according to the message content to notify users of the danger. The types of disaster that a Primary Notification can inform about are specified as “Earthquake,” “Tsunami,” “Tsunami + Earthquake,” “Test” and “Other,” regardless of the type of radio access.

The Secondary Notification contains the same kind of message as does the existing Area Mail service, which is, for example, textual information distributed from the network to the mobile terminal to inform of the epicentre, seismic intensity and other such information. That message also contains, in addition to text, a Message Identifier and Serial Number that identifies the type of disaster.

A major feature of the ETWS is compatibility with international roaming. Through standardization, mobile terminals that can receive ETWS can receive local emergency information when in other countries if the local network provides the ETWS service. These services are provided in a manner that is common to all types of radio access (3G, LTE, etc.).

Network Architecture

The ETWS platform is designed based on the Cell Broadcast Service (CBS). The ETWS network architecture is shown in Figure 2. Fig. 2 also shows the architecture for 3G network to highlight the features differences between LTE and 3G.

In the ETWS architecture for 3G, a Cell Broadcast Centre (CBC), which is the information distribution server, is directly connected to the 3G Radio Network Controller (RNC). The CBC is also connected to the Cell Broadcast Entity (CBE), which distributes information from the Meteorological Agency and other such sources.

In an LTE radio access network, however, the eNodeB (eNB) is directly connected to the core network, and eNB does not have a centralized radio control function as the one provided by the RNC of 3G. Accordingly, if the same network configuration as used for 3G were to be adopted, the number of eNB connected to the CBC would increase and add to the load on the CBC. To overcome that issue, ETWS for LTE adopts a hierarchical architecture in which the CBC is connected to a Mobility Management Entity (MME).

The MME, which acts as a concentrator node, is connected to a number of eNBs. This architecture gives advantages to the network, such as reducing the load in the CBC and reducing the processing time, and, thus preventing delay in distribution.

Message Distribution Area

In the 3G ETWS and Area Mail systems, the distribution area can be specified only in cell units, which creates the issue of huge distribution area database in CBC. In LTE ETWS, however, the distribution area is specified in three different granularities (Figure 3). This allows the operator to perform area planning according to the characteristic of the warning/emergency occasions, e.g. notice of an earthquake with a certain magnitude needs to be distributed in a certain width of area, thus allowing efficient and more flexible broadcast of the warning message.

1) Cell Level Distribution Area: The CBC designates the cell-level distribution areas by sending a list of cell IDs. The emergency information is broadcasted only to the designated cells. Although this area designation has the advantage of being able to pinpoint broadcast distribution to particular areas, it necessitates a large processing load in the network node (CBC, MME and eNB) especially when the list is long.

2) TA Level Distribution Area: In this case, the distribution area is designated as a list of Tracking Area Identities (TAIs). TAI is an identifier of a Tracking Area (TA), which is an LTE mobility management area. The warning message broadcast goes out to all of the cells in the TAIs. This area designation has the advantage of less processing load when the warning message has to be broadcast to relatively wide areas.

3) EA Level Distribution Area: The Emergency Area (EA) can be freely defined by the operator. An EA ID can be assigned to each cell, and the warning message can be broadcasted to the relevant EA only. The EA can be larger than a cell and is independent of the TA. EA is a unit of mobility management. EA thus allows flexible design for optimization of the distribution area for the affected area according to the type of disaster.

Message Distribution

The method of distributing emergency information to LTE radio networks is shown in Figure 4. When the CBC receives a request for emergency information distribution from CBE, it creates the text to be sent to the terminals and specifies the distribution area from the information in the request message (Fig. 4 (1) (2)).

Next, the CBC sends a Write-Replace Warning Request message to the MME of the specified area. This message contains information such as disaster type, warning message text, message distribution area, Primary Notification information, etc. (Fig. 4 (3)). When the MME receives this message, it sends a response message to the CBC to notify that the message was correctly received. The CBC then notifies the CBE that the distribution request was received and the processing has begun (Fig. 4 (4) (5)). At the same time, the MME checks the distribution area information in the received message (Fig. 4 (6)) and, if a TAI list is included, it sends the Write-Replace Warning Request message only to the eNB that belong to the TAI in the list (Fig. 4 (7)). If the TAI list is not included, the message is sent to all of the eNB to which the MME is connected.

When the eNB receives the Write-Replace Warning Request message from the MME, it determines the message distribution area based on the information included in the Write-Replace Warning Request message (Fig. 4 (8)) and starts the broadcast (Fig. 4 (9) (10)). The following describes how the eNB processes each of the specified information elements.

1) Disaster Type Information (Message Identifier/Serial Number): If an on-going broadcast of a warning message exists, this information is used by the eNB to decide whether it shall discard the newly received message or overwrite the ongoing warning message broadcast with the newly received one. Specifically, if the received request message has the same type as the message currently being broadcasted, the received request message is discarded. If the type is different from the message currently being broadcast, the received request message shall overwrite the ongoing broadcast message and the new warning message is immediately broadcasted.

2) Message Distribution Area (Warning Area List): When a list of cells has been specified as the distribution area, the eNB scans the list for cells that it serves and starts warning message broadcast to those cells. If the message distribution area is a list of TAIs, the eNB scans the list for TAIs that it serves and starts the broadcast to the cells included in those TAIs. In the same way, if the distribution area is specified as an EA (or list of EAs), the eNB scans the EA ID list for EA IDs that it serves and starts the broadcast to the cells included in the EA ID.

If the received Write-Replace Warning Request message does not contain distribution area information, the eNB broadcasts the warning message to all of the cells it serves.

3) Primary Notification Information: If Primary Notification information indication exists, that information is mapped to a radio channel that is defined for the broadcast of Primary Notification.

4) Message Text: The eNB determines whether or not there is message text and thus whether or not a Secondary Notification needs to be broadcasted. If message text exists, that text is mapped to a radio channel that is defined for the broadcast of Secondary Notification. The Secondary Notification is broadcast according to the transmission intervals and number of transmissions specified by the CBC. Upon the completion of a broadcast, the eNB returns the result to the MME (Fig. 4 (11)).

Radio Function Specifications

Overview : In the previous Area Mail service, only mobile terminals in the standby state (RRC_IDLE) could receive emergency information, but in ETWS, emergency information can be received also by mobile terminals in the connected state (RRC_CONNECTED), and hence the information can be delivered to a broader range of users. In LTE, when delivering emergency information to mobile terminals, the eNB sends a bit in the paging message to notify that emergency information is to be sent (ETWS indication), and sends the emergency information itself as system information broadcast. In 3G, on the other hand, the emergency information is sent through the paging message and CBS messages.

Message Distribution method for LTE: When the eNB begins transmission of the emergency information, a paging message in which the ETWS indication is set is sent to the mobile terminal. ETWS-compatible terminals, whether in standby or connected, try to receive a paging message at least once per default paging cycle, whose value is specified by the system information broadcast and can be set to 320 ms, 640 ms, 1.28 s or 2.56 s according to the 3GPP specifications. If a paging message that contains an ETWS indication is received, the terminal begins receiving the system information broadcast that contains the emergency information. The paging message that has the ETWS indication set is sent out repeatedly at every paging opportunity, thus increasing the reception probability at the mobile terminal.

The ETWS message itself is sent as system information broadcast. Specifically, the Primary Notification is sent as the Warning Type in System Information Block Type 10 (SIB10) and the Secondary Notification is sent as a Warning Message in SIB11. By repeated sending of SIB10 and SIB11 (at an interval that can be set to 80 ms, 160 ms, 320 ms, 640 ms, 1.28 s, 2.56 s, or 5.12 s according to the 3GPP specifications), the probability of the information being received at the residing mobile terminal can be increased. In addition, the SIB10 and SIB11 scheduling information is included in SIB1 issued at 80-ms intervals, so mobile terminals that receive the ETWS indication try to receive SIB10 and SIB11 after first having received the SIB1. By checking the disaster type information (Message Identifier and Serial Number) contained in SIB10 and SIB11, the mobile terminal can prevent the receiving of multiple messages that contain the same emergency information.

3G Message Distribution Method: For faster information delivery and increased range of target uers in 3G also, the CBS message distribution control used in Area Mail was enhanced. An overview of the 3G radio system is shown in Figure 5.

In the Area Mail system, a Common Traffic Channel (CTCH) logical channel is set up in the radio link, and emergency information distribution is implemented by sending CBS messages over that channel. To inform the mobile terminals that the CTCH logical channel has been set up, the RNC orders the base station (BTS) to set the CTCH Indicator information element in the system information broadcast to TRUE, and transmits the paging message indicating a change in the system information broadcast to the mobile terminals. When the mobile terminal receives the CTCH Indicator, it begins monitoring the CTCH logical channel and can receive CBS messages.

In ETWS, by including the Warning Type in the paging message indicating a change in the system information broadcast, processing for a pop-up display and alert sound processing (Primary Notification) at the mobile terminals according to the Warning Type can be executed in parallel to the processing at the mobile terminals to start receiving the CBS messages. This enhancement allows users whose terminals are in the connected state (RRC_CONNECTED) to also receive emergency information. In the previous system, it was not possible for these users to receive emergency information. Also including disaster type information (Message Identifier and Serial Number) in this paging message makes it possible to prevent receiving multiple messages containing the same emergency information at the mobile terminal.

More detailed information (Secondary Notification) is provided in CBS messages in the same way as in the conventional Area Mail system, thus achieving an architecture that is common to ETWS users and Area Mail users.

Broadcast Views

Interesting article from telecoms.com, i had missed earlier. Mobile TV is one of my pet topics so if you see me not mentioning about some important article then do mention it here.

Important points highlighted below:

As we approach the final quarter of 2007, however, the future of mobile TV is,
if anything, more uncertain. As individual carriers in different markets adopt their preferred technologies, the list of 'standard' broadcast solutions seems to be growing at the same rate as new services are launched.

In Europe, during the summer, the EC finally backed DVB-H for mobile TV rather than remaining technology neutral. In Japan and South Korea, service uptake on existing ISDB-T, and T-DMB and S-DMB, is continuing to build, albeit slowly. In the US, Verizon and AT&T have both selected Qualcomm's MediaFLO solution, which launched in March and Verizon has already gone live.

Meanwhile, BT Movio's, and therefore Virgin Mobile's, DAB solution in the UK folded due to poor uptake less than one year after launch, along with Crown Castle's DVB-H solution in the US.

On Europe, David McQueen, principal analyst Informa Telecoms&Media says: "It is possible to see the logic of support for a single mobile TV standard for Europe. GSM as a de facto standard allowed economies of scale in the industry, and made roaming easier. In theory, therefore, choosing DVB-H, is like getting the whole of Europe to go down the GSM route. Also, you are backing the frontrunner."

But backing a frontrunner that won't arrive in some markets until 2012 seems a trifle premature; at least, so says ROK TV CEO, Bruce Renny: "You have got to look at when this service is going to be available in the UK. I can tell you, 2012 at the earliest when the last of the analogues is switched off. Now 2012 in the mobile environment is a lifetime away. I mean, a month is a long time in the mobile entertainment space, quite apart from five or six years."

A recent report from Dutch analyst house Telecompaper revealed that, although three operators (KPN, Vodafone and Orange) in the Netherlands offer mobile TV, only 1.4 per cent of subscribers has watched TV using a cellphone. In fact, from a list of 22 unique data services, mobile TV was the least popular.

M:Metrics, meanwhile, found that the number of subscribers that watched any commercial programmed mobile TV and/or video, once or more, in a month in France, Germany, Spain, Italy and the UK combined, in the three months ending July 2007, was 2,386,795. It looks like a fair size number, but in reality it's only 1.12 per cent of subscribers.

In a recent strategic report Mobile TV: Broadcast Network Rollouts, Business Models and Handsets, Informa Telecoms&Media predicts the market for broadcast mobile TV devices grew from 0.81 million in 2005 to just over four million in 2006. These devices are expected to find their way into 12.3 per cent of new handset sales by 2012, representing an expected market of 178 million phones.

The ITM report states that an inflection point is expected to occur in 2009 as network rollout and device availability allow for the market to reach some level of critical mass. Informa goes on to predict that there will be 335.6 million broadcast mobile TV users worldwide by 2012, up from a mere 12.1 million expected in 2007, with an inflection point expected in 2009-2010.

According to Informa, a number of possible scenarios emerge that could enhance or dilute mobile operator strengths in the mobile TV value chain.
First, the 'discrete' business model, where the MNO chooses to provide TV services only over its own cellular networks, or via network optimised solutions, with no other broadcast network interaction. Second, the 'principal' business model, where the MNO is lead player in the broadcast TV industry, which includes some level of interaction with broadcast network services. Third, a 'converged' business model, where the MNO and others in the value chain work in cooperation to take advantage of the complementary nature of cellular and broadcast networks. And fourth, the 'bypassed' business model, where the MNO is bypassed altogether by a broadcast network operator in providing mobile broadcast TV, but may still provide an uplink.

There are advantages and disadvantages that go along with each of the above scenarios. The discrete model will appeal most to those operators that have already invested in a 3G network, since it requires minimal further investment and it ensures that the MNO retains full control of the service and therefore will derive the optimal revenues.

Not surprisingly, most of the noise coming from tech vendors at the moment surrounds rolling out new kit as part of a broadcast solution. Detractors of the discrete model point out that a unicast offering is limiting and would have a detrimental effect on other 3G services in the cell. Therefore, they say, operators need to embrace either a principal or converged model.

"We already have mobile TV on networks with 3G. So if you have invested in a 3G network it is very cheap to deploy a service," points out Alban Couturier, mobile TV product manager, Thomson. "But for users the data cost is high. Which puts people off. Using DVB-H you have lots of costs to deploy, but new customer additions are cheap. Once you reach critical mass, the costs become very low. You can't have that with 3G," he says.

One firm only too happy to be involved in Vodafone's discrete model is British Sky Broadcasting. Steven Nuttall, director commercial group, British Sky Broadcasting, speaking on a recent Telecoms.com webinar, outlined how pleased he is with the pace of mobile TV in the UK: "A year or so into running a service, we've got several hundred thousand customers, paying real money to use it. We've got millions of people using more general mobile services, many of which are video, so I don't know at what point you would say that video is a mass market. I think it is reasonable to say that at a minimum we're pretty close to that point already."

ROK TV's Renny says his firm offers a discrete solution for carriers that have yet to rollout 3G networks. "There are 100 million people worldwide who have signed up to 3G. It sounds impressive, but that's about three per cent of the global mobile market. A 100 million uptake across a three billion market place is, in anyone's language, niche."

ROK offers the ability to stream video over what Renny says are vastly underused GPRS networks. "I think linear TV over mobile phones will prove very popular indeed. The question is how many people will be willing to pay a subscription service to receive linear TV on their mobile phone? Particularly, when you get all that at home for free. The notion of 'build it and they will come' is flawed," he says.

Renny points out that TV on the mobile is not the same as broadcast TV. "It isn't viewed in the same way, it is delivered through a different vehicle and it is a different animal completely. Broadcast TV available on mobile phones will prove popular, but only as a value add in a general mobile bundle. As a stand alone subscription service it will have very limited uptake indeed," he says.

Another firm that advocates taking full advantage of existing resources is IPWireless. The firm's TDtv offering uses the 5Mhz of UMTS TDD spectrum that the majority of 3G operators across Europe have at their disposal. Thanks to the 3GPP specified MBMS (Multimedia Broadcast and Multicast Services), operators can take an existing 3G network and render it multicast, rather than unicast.

The firm had a multi-operator trial in the UK city of Bristol last year. CMO Jon Hambidge told MCI the technology matches DVB-H and MediaFLO in terms of available channels and he is confident that an operator in Europe will go live with the service sometime next year.

"A lot of people are questioning the need for broadcast services," says Hambidge. "One of the reasons is that they are very expensive. I've seen some economic analysis on DVB-H showing that it has a very hard time breaking even down at a ??????5 type level. I think the economic analysis we've seen shows that TDtv, for an MNO, is going to breakeven somewhere around a five times lower price point. So it really keeps mobile TV as a 3G service."

While ROK's Renny may think the 'build it and they'll come' scenario is flawed, Qualcomm would disagree. The San Diego firm's subsidiary MediaFLO USA rolled out its mobile TV solution across America going live in March 2007. Subsequent to that, Verizon launched a service on the network, and will soon be followed by AT&T.

"There are a lot of challenges with that pure wholesale approach," says Omar Javaid, VP of global strategy and business development at Qualcomm. "The interesting thing about mobile TV is that it is a converged service and there are so many different industries involved. When the telecommunications industry is looking at it, they're looking at it primarily from an infrastructural and technology approach, and what tends to get missed in that equation is the whole content rights issue."

Javaid highlights a common assumption that the free-to-air broadcasters will simply provide their content for mobile TV platforms. While the content providers will maintain that the rights for free-to-air broadcast do not extend to this kind of platform. So the content rights need renegotiating, and they're not free. "When you work out the match it becomes much more expensive. Both from a wholesale perspective and then subsequently a retail perspective. I don't think it is impossible to do, but somebody ends up having a pretty marginal business," he says.

Each of the networks under consideration for delivering mobile TV has their own advantages and drawbacks. The most recurrent themes are the ability to provide a one-to-many broadcast topology, network and device costs, reception quality, regulation, spectrum allocation and efficiency, handset manufacturer and network vendor support, and technology fragmentation in different geographic regions.

Broadcast networks use spectrum allocation and one-to-many broadcast efficiently, unlike many of the mobile TV point-to-point offerings available over cellular networks, even 3G, which put the network under enormous strain. The broadcast network technologies, such as DVB-H, MediaFLO and DMB, are far more efficient in terms of time and bandwidth usage, which means they are more cost effective, but they do not enable fully interactive content, something that the cellular networks can provide. However, fragmentation of the market into different technologies using different frequencies is a major risk for the nascent mobile broadcast TV market.

For now, the most sensible plan looks like the one advocated by Anders Kalvemark of Ericsson: "I think we will see various types here. Our main strategy is that the operators will have their own 3G networks and then they will enable broadcast capabilities, which could be NGN, so the evolution of 3G. Dedicated broadcast networks will probably arrive, they already have in a few countries, but it is obviously a large investment. I wouldn't be surprised if we saw a consortium of operators coming together to set up these types of network."

Alban Couturier of Thomson: "3G operators should leverage existing services by offering a hybrid of services. They should offer the most popular channels over broadcast, but they should offer the long tail over 3G because it is ideally suited for video on demand."

Of the four models described by Informa Telecoms&Media, it is possible that, for the longer term success of the mobile TV industry, cooperation and understanding between the players in the value chain, providing a converged solution will ensure the best possible experience for the customer. This allows broadcast media to be combined with, and used to complement, cellular communications to enrich the user experience and encourage interactivity. There will undoubtedly be problems with implementing this scenario with so many large brands fighting turf wars. But, if the industry can overcome its natural competitiveness in this instance, it will allow the delivery of new revenue sources for all in the value chain.

However, mobile operators currently offer mobile video and TV services over their own 2.5G and 3G networks and the advent of broadcast networks in the mobile space will undoubtedly affect their stature in the ecosystem. Although much is made regarding operators providing a return channel for interactive services, a potential future scenario could be one where even the provision of this channel is taken away as return channels become more prevalent through the broadcast network, weakening the position of the mobile operator in the mobile TV value chain.

In contrast, the migration by the operators to next-generation 3.5G and 4G networks could also negate the need by the operator to involve broadcast networks in the provision of mobile TV as these will allow for greater speed and bandwidth to provide a more cost-effective mobile TV offering.

Back in 2006, Virgin Mobile's head of mobile TV Paul Coombes told MCI his firm was launching using a DAB solution because it was "available". Right now, that choice seems like folly. Not surprisingly, neither BT nor Virgin wanted to comment for this piece. In fairness, there really are no sure things in this industry. But right now, trying to back a winning solution looks more like an expensive gamble rather than a sound investment.

The 'Phantom Cell' concept in LTE-B

One of the LTE-B proposals by NTT Docomo is this 'Phantom Cell' concept. A recent article from the IEEE Communications Magazine expands this further:


Phantom Cell Concept — In the current deployments, there are a number of capacity solutions for indoor environments such as WiFi, femtocells, and in-building cells using distributed antenna systems (DAS). However, there is a lack of capacity solutions for high-traffic outdoor environments that can also support good mobility and connectivity. Thus, we propose the concept of macro-assisted small cells, called the Phantom Cell, as a capacity solution that offers good mobility support while capitalizing on the existing LTE network. In the Phantom Cell concept, the C-plane/U-plane are split as shown in Fig. The C-plane of UE in small cells is provided by a macrocell in a lower frequency band, while for UE in macrocells both the C-plane and U-plane are provided by the serving macrocell in the same way as in the conventional system. On the other hand, the Uplane of UE in small cells is provided by a small cell using a higher frequency band. Hence, these macro-assisted small cells are called Phantom Cells as they are intended to transmit UE-specific signals only, and the radio resource control (RRC) connection procedures between the UE and the Phantom Cell, such as channel establishment and release, are managed by the macrocell.

The Phantom Cells are not conventional cells in the sense that they are not configured with cell specific signals and channels such as cell-ID-specific synchronization signals, cell-specific reference signals (CRS), and broadcast system information. Their visibility to the UE relies on macrocell signaling. The Phantom Cell concept comes with a range of benefits. One important benefit of macro assistance of small cells is that control signaling due to frequent handover between small cells and macrocells and among small cells can be significantly reduced, and connectivity can be maintained even when using small cells and higher frequency bands. In addition, by applying the new carrier type (NCT) that contains no or reduced legacy cell-specific signals, the Phantom Cell is able to provide further benefits such as efficient energy savings, lower interference and hence higher spectral efficiency, and reduction in cellplanning effort for dense small cell deployments.

To establish a network architecture that supports the C/U-plane split, and interworking between the macrocell and Phantom Cell is required. A straightforward solution to achieve this is to support Phantom Cells by using remote radio heads (RRHs) belonging to a single macro eNB. This approach can be referred to as intra-eNB carrier aggregation (CA) using RRHs. However, such a tight CA-based architecture has some drawbacks as it requires single-node operation with low-latency connections (e.g., optical fibers) between the macro and Phantom Cells. Therefore, more flexible network architectures should be investigated to allow for relaxed backhaul requirements between macro and Phantom Cells and to support a distributed node deployment with separated network nodes for each (i.e., inter-eNB CA).

Multicast Operation on Demand (MooD) and Service Continuity for eMBMS

Many regular readers of this blog are aware that back in 2014 I wrote a post looking critically at LTE-Broadcast business case and suggested a few approaches to make it a success. Back in those days, 2014 was being billed as the year of LTE-Broadcast or eMBMS (see here and here for example). I was just cautioning people against jumping on the LTE-B bandwagon.

According to a recent GSA report 'LTE Broadcast (eMBMS) Market Update – March 2018':

• thirty-nine operators are known to have been investing in eMBMS demonstrations, trials, deployments or launches
• five operators have now deployed eMBMS or launched some sort of commercial service using eMBMS

Its good to see some operators now getting ready to deploy eMBMS for broadcast TV scenarios. eMBMS will also be used in Mission Critical Communications for the features described here.

In a recent news from the Australian operator Telstra:

Telstra is now streaming live sports content to a massive base of around 1.2 million devices each weekend and sports fans consume 37 million minutes of live content over our apps on any given weekend.

This increase brings new challenges to the way traffic on our mobile network is managed. Even though a large group of people might be streaming the same real-time content at the same time, we still need to ensure a high quality streaming experience for our customers.

This challenge makes our sporting apps a prime use case for LTE-Broadcast (LTE-B).

Earlier this year, we announced we would be turning on LTE-B functionality on the AFL Live Official app for Telstra customers with Samsung Galaxy S8 and Galaxy S9 devices. Following extensive testing, Telstra is the only operator in Australia – and one of the first in the world – to deploy LTE-B into its mobile network.

At a live demonstration in Sydney, over 100 Samsung Galaxy S8 and Galaxy S9 devices were on display showing simultaneous high definition content from the AFL Live Official app using LTE-B.

Its interesting to note here that the broadcast functionality (and probably intelligence) is built into the app.

According to another Telstra news item (emphasis mine):

The use of LTE-Broadcast technology changes the underlying efficiency of live video delivery as each cell can now support an unlimited number of users watching the same content with improved overall quality. To date though, LTE-B technology has required that a dedicated part of each cell’s capacity be set aside for broadcasting. This had made the LTE-B business case harder to prove in for lower streaming demand rates.

This has now changed as Telstra and our partners have enabled the world’s first implementation of the Multicast Operation on Demand (MooD) feature whereby cells in the network only need to configure for LTE-B when there are multiple users watching the same content.

This combined with the Service Continuity feature allows mobile users to move around the network seamlessly between cells configured for LTE-B and those which are not.

Earlier this year we announced our intention to enable LTE-Broadcast (LTE-B) across our entire mobile network in 2018. With MooD and service continuity we are one step closer to that goal as we head into another year of major growth in sporting content demand.

Supported by technology partners Ericsson and Qualcomm, Telstra has now delivered world first capability to ensure LTE-B can be delivered as efficiently as possible.

Service Continuity will allow devices to transition in and out of LTE-B coverage areas without interruption. For instance, you might be at a music festival streaming an event on your phone but need to leave the venue and make your way back home (where LTE-B is not in use). Service Continuity means you can continue to watch the stream and the transition will be seamless – even though you have the left the broadcast area.

Taking that a step further, MooD allows the network to determine how many LTE-B compatible devices in any given area are consuming the same content. MooD then intelligently activates or deactivates LTE-B, ensuring the mobile network is as efficient as possible in that location.

For example, if a die-hard football fan is streaming a match we will likely service that one user with unicast, as that is the most efficient way of delivering the content. However if more users in the same cell decide to watch the match, MooD makes the decision automatically as to whether it is more efficient to service those users by switching the stream to broadcasting instead of individual unicast streams.

Its good to see Ericsson & Qualcomm finally taking eMBMS to commercial deployment. Back in 2015, I added their videos from MWC that year. See post here.

I think the Telstra post already provides info on why MooD is needed but this picture from Qualcomm whitepaper above makes it much clearer. Back in 3G MBMS and early days or eMBMS, there used to be a feature called counting, MooD is effectively doing the same thing.

For Service Continuity, this paper 'Service Continuity for eMBMS in LTE/LTE-Advanced Network: Standard Analysis and Supplement' by Ngoc-Duy Nguyen and Christian Bonnet has interesting proposal on how it should be done. I cannot be sure if this is correct as per the latest specifications but its interesting to learn how this would be done when the user moves out of coverage area in Idle or connected mode.

Note that this Expway paper also refers to Service continuity as Session continuity.

Related posts:

• Telstra's LTE-B Push
• Reliance Jio getting ready for LTE-Broadcast (eMBMS) rollout

Mobile TV: Any Luck?

Mobile TV, once touted as 'the technology' does not yet seem to be having any luck.

Mobile television suffered another setback when the U.S. House of Representatives voted Wednesday to delay the broadcast airwaves' long-planned transition to all-digital services from Feb. 17 to June 12, a move that effectively forces Qualcomm to postpone plans to increase its MediaFLO TV footprint until early summer. Qualcomm previously said it would turn on FLO TV service in more than 40 additional U.S. cities on Feb. 17, an expansion timed to coincide with a federal law mandating that all full-power television stations must terminate analog broadcasting on that date. The transition to digital television frees up the 700 MHz spectrum auctioned last year by the FCC--Qualcomm spent more than $500 million acquiring eight licenses during the auction, and hopes to serve about 200 million potential mobile TV subscribers in more than 100 U.S. markets by the close of 2009. But with the Nielsen Company estimating that 6.5 million American households remain unprepared for the switch to digital TV, and Congress mulling a stimulus package that includes as much as $650 million in financing for coupons to ease the transition, Qualcomm must now sit tight for four additional months.

According to a report from Nielsen Mobile, only 5% of all U.S. cell phone owners subscribe to a mobile TV service. Yet that number is the highest out of of all the other worldwide markets tracked by the company. Only France and Italy came close, each at 4 percent. According to Nielsen, mobile video use isn't more prevalent due to lack of differentiating capabilities, high cost, and lack of compelling content. In fact, we are now even seeing mobile video's plateau - a point where you would normally expect to see adoption slow considerably.

In the U.S., 10.3 million mobile phone subscribers watch video content on their mobile phones each month. These clips from mobile web sites, subscriptions delivered by the carrier, or through mobile "live" TV programming. But the mobile video subscription market has barely grown during the past year. In Q3 2007 it was at 6.4 percent and by Q3 2008 it was only 7.3 percent. And only 26% of subscribers who paid for mobile video services during the third quarter of 2008 used them at least once a month.

The Open Mobile Video Coalition (OMVC), announced that a new mobile DTV service will soon arrive in 22 U.S. cities, covering 35% of U.S. television households. The mobile service aims to provide live, local and national over-the-air digital television to mobile devices.

Included in the service are 63 stations from the 25 major broadcasters that are on board. Those include NBC Television, Gannett Broadcasting, Sinclair Broadcast Group, Fox Television, Belo Corp., Grey Television, Scripps Television, Hearst Argyle Television, ION Media Networks and Lin Television.

This mobile TV service may succeed where others have failed because it bypasses the carriers altogether. Instead, the service uses an ATSC broadcasting system to beam signals directly from the station to the mobile devices themselves. This unburdens the carriers from having to support the data transmissions - they just have to sell the phones.

If France doesn't decide to go down the DVB-H route, there are many who think that could signal the end of the road for the mobile broadcast standard in most European markets
According to one industry commentator, there's a lot riding on the French. Our source, who would rather not be named, thinks that if the French market does not decide to follow the DVB-H standard this year, then that could be the end for the mobile broadcast standard in the region as a whole.

Certainly, the signs have not been good elsewhere - and the industry is dogged by accusations of self-interest. For example, despite operator pressure, Nokia, which sits on 40-50% market share in most European markets, has not moved as fast as the industry had hoped to push DVB-H and DRM technology into its handsets.

According to the head end vendors, and this is a surprisingly widely held view, the issue has been that Nokia has tried to tie the sale of its network infrastructure to the development of its handset range.

"Nokia is saying, give us the head end, and we will give you the handsets," one competing vendor told us.

The China Digital Television Terrestrial Broadcasting (DTTB) System Standard, also known as GB20600-2006, became the mandatory national DTTB standard in August 2007.

GB20600-2006 was designed to deliver a consistent, high-quality digital TV viewing experience no matter where consumers are sitting: in their living room watching television or on a high-speed train watching shows on their cell phones. The technology can broadcast audio and video at transmission rates of greater than 24 Mbps to consumer devices. Because the mobile reception capability is inherently built into the standard, these consumer devices now have a mobile TV feature that works not only when stationary, but even while traveling at speeds greater than 200 km per hour.

The China television market is in the midst of a broadcast revolution because of this new free-to-air terrestrial DTV standard. GB20600-2006 is spurring station owners to broadcast HDTV signals to TVs and set-top boxes, creating a market opportunity that is larger than any other in the world. With 380 million television households, China is home to more televisions than any other country in the world. And nearly 70 percent of those households receive their programming via roof-top antenna.

At the same time, the GB20600-2006 standard is creating a significant new market for mobile TV services. There are more than 600 million cell phone subscribers in China and nearly seven million new mobile phones are purchased each month. Now that the free-to-air HDTV broadcast signal has become a reality, manufacturers of cell phones and other handheld mobile devices are rushing to incorporate mobile TV reception into their products.

Technical details are available here.

China also has its mobile specific TV standard called the CMMB (China Multimedia Mobile Broadcasting). Leading mobile TV chip-maker Siano Mobile Silicon's CMMB receiver chip, the SMS1180, has been selected to power CMMB mobile TV for leading Chinese phone-makers ZTE, Tianyu, CEC Telecom and MP3/4 giant AIGO.

The number of mobile TV subscribers in Korea grew by almost 60% in 2008 following aggressive marketing campaigns and the Beijing Olympics, reports the Yonhap News Agency.

The number of DMB users totalled 17.25 million at the end of 2008, up 59.9% from a year earlier, according to the Terrestrial-DMB Special Committee. South Korea started the world’s first DMB service in 2005, operated through terrestrial and satellite broadcasts.

According to the committee, which represents six service carriers, 15.4 million terrestrial DMB devices, including mobile phones, were sold as of the end of 2008, up 70% from the previous year. The number of subscribers to the satellite platforms (S-DMB) rose 45% annually to 1.85 million last year.

Telegent Systems announced that it has shipped more than 20 million mobile TV receivers since it launched the products in 2007.

The TV receivers have been rapidly adopted by consumers who want to watch the same TV on their mobiles that they enjoy on their home TVs.

Telegent’s receivers use the existing broadcast infrastructure, and allow consumers to watch local programming.

Telegent’s latest success is a deal with Telefónica Móviles Perú, to bring mobile TV to Telefónica’s ZTE i766 handset.

In order to continue its rapid growth, Telegent is expanding into the PC TV market in 2009 and adopting the digital standard DVB-T.

5G for Content Acquisition and Distribution

The Cambridge Wireless (CW) Content Production & Delivery group recently delivered a two part webinar series exploring ‘5G for content acquisition and distribution’ These online events introduced participants to the state of play with 5G for content distribution and production and the path to delivering the benefits 5G.

Aspirational discussion of benefits of 5G for content production and distribution needs to be turned into operational reality. 5G will enhance what is possible to be achieved with current mobile systems and the advantages to distribution and consumption are obvious through bigger pipes and enhanced agility to support ever evolving content and application platforms. The possibilities for content production and acquisition are also exiting but may be less obvious. 5G will allow service and capacity to be delivered where required through use of small cell and potentially highly localised private 5G networks, edge computing and support of a wide range of equipment and applications (not just those use cases directly involved in content acquisition).

The first session on 24 Nov 2020 in the series considers the role of 5G for content distribution and security. It covers the role of 5G for the creation of a more varied and vibrant ecosystem for content and the desire of some content creators for greater focus on security.

Henry Johnson, Director, Plum Consulting, '5G opportunities in the provision of content distribution' - 5G services promise to provide connectivity performance in terms of bandwidth and latency which have hitherto been possible only with fixed network connectivity. This session will look into the capabilities and potential limitations of 5G services once deployed and what that might mean for content delivery to consumers. [PPT presentation]

Malcolm Brew, University of Strathclyde, ‘5G-enabled remote broadcast’ - Malcolm will share some Strathclyde’s insights over the last 10 years in working with BBC and Ofcom on ‘Spectrum Sharing’ and how this has recently been lead to working in an IBC Accelerator Program ‘5G In Remote Production’ [PDF] 

For limited time, the recording is available here.

The 3G4G Blog: LTE / 5G Broadcast Evolution - https://t.co/nMM6VvxGbg via @5Gxcast #3G4G5G #IEEE5G #5GIEEE #eMBMS #LTEBroadcast #MissionCriticalComms pic.twitter.com/aSxdsFkX9A

— 3G4G (@3g4gUK) August 29, 2019

The following is the description from session 2, on 2nd Dec 2020:

Join the CW Content Production and Delivery Group’s aspirational discussion of benefits of 5G for content production and distribution needs to be turned into operational reality.

There is no doubt 5G will enhance what is possible to be achieved with current mobile systems and the advantages to distribution and consumption are obvious through bigger pipes and enhanced agility to support ever evolving content and application platforms.

The possibilities for content production and acquisition are also exciting, but may be less obvious. 5G will allow service and capacity to be delivered where required through use of small cell and potentially highly localised private 5G networks, edge computing and support of a wide range of equipment and applications (not just those use cases directly involved in content acquisition).

Ian Wagdin, Senior Technology Transfer Manager, BBC R&D, '5G in Content Production, work in standards and deployments' - A look at what’s here and what’s coming and how 5G may impact broadcast workflows. [PDF]

Paola Sunna, Technology and Innovation Department, EBU, '5G for Content Production' - EBU perspective on 5G for professional content production and challenges/ambitions in the Horizon 2020 project 5G-RECORDS. [PDF] 

For limited time, the recording is available here.

A nice talk looking at 5G and Broadcast - 'BBC, 5G and me' by Ed King, Principal Architect, BBC at @TheIET #5GUnleashed 2020 conference - https://t.co/RtTIxZnvN4#Free5GTraining #eMBMS #5Gbroadcast pic.twitter.com/j0d6r7Xqeq

— 5G Training (@5Gtraining) March 6, 2020

Other Recent News / Articles / Videos on 4G/5G Broadcast:

• SoftBank Corp. Showcases 5G-powered Entertainment and Advanced Technologies at Pop Culture Complex (link)
• 5G TODAY: BAVARIA’S BROADCAST TRIALS (link)
• Webinar: The role of broadcast and multicast in 5G-TOURS: High-quality video services distribution (link)
• Delivering Media with 5G Technology: FeMBMS, 5G-Xcast and beyond (link)
• 5G TODAY: 5G Broadcast trial using FeMBMS (link)
• 5G Today: On the Road to 5G Broadcast (link)

Related Posts:

• The 3G4G Blog: LTE / 5G Broadcast Evolution
• The 3G4G Blog: 5G Dynamic Spectrum Sharing (DSS)
• The 3G4G Blog: Multicast Operation on Demand (MooD) and Service Continuity for eMBMS 

E-UTRAN Mobility Drivers and Limitations

Many years back, when things used to be simple, I wrote a tutorial about Handovers in UMTS. It would be very difficult to write a similarly simple tutorial for LTE. Things are a bit complicated because there are many different conditions in which handovers can take place.

It was also easier to visualise the Intra-frequency and Inter-frequency handovers in UMTS and you can probably do the same to some extent in LTE but with things getting more complicated and carrier aggregation, classifying handovers in these categories may be difficult.

3GPP TS 36.300 has an informative Annex E which details the scenarios in which handovers and cell change can/will take place.

It is best to go and see Annex E in detail. Here is a bit of summary from there:

Intra-frequency mobility: intra-frequency mobility is the most fundamental, indispensable, and frequent scenario. With the frequency reuse being one in E-UTRAN, applying any driver other than the “best radio condition” to intra-frequency mobility control incur increased interference and hence degraded performance.

Inter-frequency mobility: as in UTRAN, an operator may have multiple carriers/bands for E-UTRAN working in parallel. The use of these frequency layers may be diverse. For example, some of these frequency layers may utilise the same eNB sites and antenna locations (i.e., co-located configuration), whereas some may be used to form a hierarchical cell structure (HCS), or even be used for private networks. Some frequency layers may provide MBMS services, while some may not. Moreover, E-UTRAN carriers/bands may be extended in the future to increase capacity.

Inter-RAT mobility: the aspects that need to be considered for inter-RAT are similar to those for inter-frequency. For mobility solutions to be complete with the inter-RAT drivers, relevant updates would be necessary on the legacy (UTRAN/GERAN) specifications. This will add to the limitations, which are evidently more effective in inter-RAT.


The drivers for mobility control are:

Best radio condition: The primary purpose of cell reselection, regardless of intra-frequency, inter-frequency, or inter-RAT, is to ensure that the UE camps on/connects to the best cell in terms of radio condition, e.g., path loss, received reference symbol power, or received reference symbol Es/I0. The UE should support measurements to suffice this aspect.

Camp load balancing: This is to distribute idle state UEs among the available bands/carriers/RATs, such that upon activation, the traffic loading of the bands/carriers/RATs would be balanced. At least the path loss difference between different bands should be compensated to avoid UEs concentrating to a certain frequency layer.

Traffic load balancing: This is to balance the loading of active state UEs, using redirection for example. In E-UTRAN, traffic load balancing is essential because of the shared channel nature. That is, the user throughput decreases as the number of active UEs in the cell increases, and the loading directly impacts on the user perception.

UE capability: As E-UTRAN bands/carriers may be extended in the future, UEs having different band capabilities may coexist within a network. It is also likely that roaming UEs have different band capabilities. Overlaying different RATs adds to this variety.

Hierarchical cell structures: As in UTRAN, hierarchical cell structures (HCS) may be utilised in E-UTRAN to cover for example, indoors and hot spots efficiently. It is possible that E-UTRAN is initially deployed only at hot spots, in which case this driver becomes essential for inter-RAT, not just for inter-frequency. Another use case would be to deploy a large umbrella cell to cover a vast area without having to deploy a number of regular cells, while providing capacity by the regular cells on another frequency.

Network sharing: At the edge of a shared portion of a network, it will be necessary to direct UEs belonging to different PLMNs to different target cells.

Private networks/home cells: Cells that are part of a sub-network should prioritise the camping on that sub-network. UEs that do not belong to private sub-networks should not attempt to camp or access them.

Subscription based mobility control: This mobility driver aims to limit the inter-RAT mobility for certain UEs, e.g., based on subscription or other operator policies.

Service based mobility control: An operator may have different policies in allocating frequencies to certain services. For example, the operator may concentrate VoIP UEs to a certain frequency layer or RAT (e.g., UTRAN or GERAN), if evaluations prove this effective. UEs requiring higher data rates may better be served on a frequency layer or RAT (e.g., E-UTRAN) having a larger bandwidth. The operator may also want to accommodate premium services on a certain frequency layer or RAT, that has better coverage or larger bandwidth.

MBMS: For Release-9, no new mobility procedures compared to Release-8 are included specifically for MBMS. In future releases the following should be considered. As MBMS services may be provided only in certain frequency layers, it may be beneficial/necessary to control inter-frequency/RAT mobility depending on whether the UE receives a particular MBMS service or not. For MBMS scenarios only, UE based service dependent cell reselection might be considered acceptable. This aspect also depends on the UE capability for simultaneous reception of MBMS and unicast.


While the issues mentioned above drive E-UTRAN towards “aggressive” mobility control, the limiting factors also have to be considered:

UE battery saving: The mobility solution should not consume excessive UE battery, e.g., due to measurements, measurement reporting, broadcast signalling reception, or TA update signalling.
Network signalling/processing load: The mobility solution should not cause excessive network signalling/processing load. This includes over-the-air signalling, S1/X2 signalling, and processing load at network nodes. Unnecessary handovers and cell reselections should be avoided, and PCH and broadcast signalling, as well as dedicated signallings, should be limited.

U-plane interruption and data loss: U-plane interruption and data loss caused by the mobility solution should be limited.

OAM complexity: The mobility solution should not demand excessive efforts in operating/maintaining a network. For example, when a new eNB is added or an existing eNB fails, the mobility solution should not incur excessive efforts to set up or modify the parameters.

More details available in Annex E of 3GPP TS 36.300

A Twitter discussion on eMBMS

@zahidtg: Samsung has demoed eMBMS using Anritsu RTD system - http://bit.ly/PCGb99  - But is any operator interested?

Korean consumer electronics giant Samsung has successfully demonstrated the clear delivery of television broadcast signals over an LTE 4G wireless network. 

Samsung is using evolved Multimedia Broadcast Multicast Service (eMBMS) technology and has tapped test & measurement specialist Anritsu's Rapid Test Designer (RTD) and MD8430A to simulate the LTE network environment used for the demonstration. 

eMBMS technology allows carriers to adjust coverage and capacity as needed, allowing for more efficient use of network resources in order to better handle the heavy traffic load that broadcast video would present. 

Samsung is actively looking to add more content to the value proposition for its phones. It has deployed its own Hub strategy for its Galaxy line of smartphones, which includes a Music Hub, Movies Hub and Games Hub, all of which give the handset-maker a new incremental revenue stream. A TV Hub that could support live TV content in addition to on-demand episode downloads could add a compelling new wrinkle in that pseudo-walled garden approach. 

Samsung is also instrumental in bringing mobile TV to market via the Dyle initiative for mobile DTV—a service that offers live broadcast feeds from local TV affiliates over separate, dedicated broadcast spectrum. No. 5 U.S. wireless carrier MetroPCS just went live with Dyle service and a Samsung mobile DTV-compatible smartphone.

@KimKLarsen: Depends on whether an operator believes in the broadcast over mobile model. Mobile User trends seems not in favor at least in WEU.

@zahidtg: I agree and thats why I dont think broadcast will work in the short term. Would be different is Apple were to create biz model:)

@KimKLarsen: though the question is whether they (Apple/Google) really need eMBMS for executing such a business model ... I guess not really?!

@KimKLarsen: I have a couple of beautiful white papers on satellite (w & wo terrestrial component) eMBMS using S-band together w Apple or Google

@zahidtg: True. My point is that they are the ones who can create a new biz model on it, operators cant be bothered. Too much hassle.

@KimKLarsen: too much hassle, too little new revenue, risky ROI, insufficient scale, etc.. an Apple or alike might overcome due to shear scale!

@KimKLarsen: though w a satellite (w. city based terrestrial component) based eMBMS system you cover large landmass & pop & get the Scale!

@Qualcomm_Tech: I think the best initial use case for #eMBMS is to selectivley use it as venue casting at stadiums/exhibitons etc.

@kitkilgour: "ClipCasting" has been the main eMBMS use case - stadia, or catching up on your 1min news at stations

@Qualcomm_Tech: True, Any content destined to venue users, incl. live/real-time can leverage eMBMS- huge capacity increase

@KimKLarsen: I agree! Might be interesting! But can this really justify eMBMS as a service for mass adaption?

@KimKLarsen: when will eMBMS be supported in Gobi? & when can we expect this to be standard in all LTE terminal devices?

@kitkilgour: It's networks as well as devices. MBMS has always been hampered by needing to reach the cell edge ...

@kitkilgour: ... with limited / no power control whilst minimising interference to others

@KimKLarsen: great feedback! Thanks! Do you see a need for denser networks to deliver a uniform MBMS service than for standard data services?

@KimKLarsen: one of the challenges we have had in nominal terrestrial MBMS designs have been link budget requirements! Any good sources?

@Qualcomm_Tech: challenge’s been having enough penetration of multicast devices. Venue cast solves that problem #1000x

@KimKLarsen: Sounds like Venue Cast is The Main Driver for eMBMS adoptation? (hmmm?) What's the Revenue Source? #42x

@KimKLarsen: I don't understand how Venue Cast can Drive MC Device Uptake? The other way around more reasonable! #42x

@Qualcomm_Tech: Target specific groups, eg season ticket holders & offer attractive device/content/plan bundles #1000x

Participants:

@zahidtg = Zahid Ghadialy
@KimKLarsen = Dr. Kim Larsen
@Qualcomm_Tech = Qualcomm_Tech
@kitkilgour = Kit Kilgour



In other news, Huawei Launches eMBMS Innovation Center to Develop LTE Solutions:

Huawei, a leading global information and communications technology (ICT) solutions provider, today announced the launch of an enhanced Multimedia Broadcast Multicast Service (eMBMS) innovation center in Shenzhen in order to develop end-to-end eMBMS solutions and LTE applications. 

eMBMS is a 3GPP R9 standard for mobile video that enables a higher transfer capacity over typical MBMS technologies. Huawei's eMBMS innovation center will focus on on-demand video services and broadcast information based on eMBMS. This will enrich LTE applications and accelerate the development of the eMBMS industry chain, which includes chipsets, devices, and network equipment.

In addition to developing solutions, the innovation center will also serve as an experience center for operators. Video, mobile TV, and advertisements will be showcased via mobile smart devices employing Huawei's eMBMS solution. Global operators from Europe, Asia, the South Pacific and other regions have already visited the center to experience its LTE demonstrations.

Huawei has been committed to the growing mobile video market since 2006. According to the Global mobile Supplier Association's (GSA) “Mobile Broadband Status Report”, over four billion people watch videos on YouTube every day. This large-scale usage is leading to increased revenue. According to a report from Global Industry Analysts, revenue from the mobile video market will reach USD30 billion by 2017. Huawei's eMBMS research team works closely with operators, chipset and device manufactures and other partners to further the development of the industry for the benefit of all end users.

Huawei's LTE division has been committed to providing the best commercially performing network, the best end user experience through devices and innovative services, as well as end-to-end convergent solutions for helping operators with their business success. Huawei's eMBMS innovation center will push the development of mobile video well into the future.