1、 ATIS-0700007 ATIS Standard on - IMPLEMENTATION GUIDELINES AND BEST PRACTICES FOR GSM/UMTS CELL BROADCAST SERVICE ATIS is the leading technical planning and standards development organization committed to the rapid development of global, market-driven standards for the information, entertainment and
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4、.S. contributor to the International Telecommunication Union (ITU) Radio and Telecommunications Sectors, and a member of the Inter-American Telecommunication Commission (CITEL). For more information, please visit . Notice of Disclaimer Technical Specification Group Terminals; Technical realization o
5、f Cell Broadcast Service (CBS).1Ref 2 3GPP TS 25.419, 3rd Generation Partnership Project; Technical Specification Group RAN; UTRAN Iu-BC Interface: Service Area Broadcast Protocol (SABP).11This document is available from the 3rdGeneration Partnership Project (3GPP) . ATIS-0700007 2 Ref 3 3GPP TS 44.
6、012, 3rd Generation Partnership Project; Technical Specification Group GSM EDGE Radio Access Network; Short Message Service Cell Broadcast (SMSCB) support on the mobile radio interface.1Ref 4 3GPP TR 25.925, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radi
7、o interface for broadcast/multicast service.1Ref 5 3GPP TS 25.324, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Broadcast/Multicast Control (BMC).1Ref 6 3GPP TS 25.212, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network;
8、Multiplexing and channel coding (FDD).1Ref 7 3GPP TS 25.222, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Multiplexing and channel coding (TDD).1Ref 8 3GPP TS 25.402, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Sy
9、nchronization in UTRAN Stage 2.1 Ref 9 ATIS-0700006, Commercial Mobile Alerts Service (CMAS) for GSM/UMTS Using Cell Broadcast Service.2Ref 10 ATIS-0700008, Cell Broadcast Entity (CBE) to Cell Broadcast Center (CBC) Interface Specification.2Ref 11 3GPP TS 48.058, 3rd Generation Partnership Project;
10、Technical Specification Group GSM/EDGE Radio Access Network; Base Station Controller - Base Transceiver Station (BSC - BTS) interface; Layer 3 specification.1 3 DEFINITIONS, ACRONYMS, & ABBREVIATIONS 3.1 Definitions 3.1.1 Cell Broadcast Service. Cell Broadcast Service (CBS) permits a number of unack
11、nowledged general CBS messages to be broadcast to all receivers within a particular region. CBS messages are broadcast to defined geographical areas known as Cell Broadcast areas. 3.1.2 Cell Broadcast Area. Cell Broadcast Area is the geographical area for the broadcast of the CBS message. Cell Broad
12、cast Areas may be comprised of one or more cells or the entire wireless operator network. Individual CBS messages will be assigned their own Cell Broadcast Areas. 3.1.3 Cell Broadcast Service (CBS) Page. A Cell Broadcast Service (CBS) page comprises 82 octets, which, using the default character set,
13、 equates to 93 characters. Up to 15 of these pages may be concatenated to form a CBS message. Each page of such a CBS message will have the same message identifier and the same serial number. 3.2 Acronyms & Abbreviations ATIS Alliance for Telecommunications Industry Solutions BMC Broadcast/Multicast
14、 Control BSC Base Station Controller 2This document is currently awaiting publication by the Alliance for Telecommunications Industry Solutions (ATIS), 1200 G Street N.W., Suite 500, Washington, DC 20005. . ATIS-0700007 3 BTS Base Transceiver System CB Cell Broadcast CBC Cell Broadcast Center CBCH C
15、ell Broadcast Channel CBE Cell Broadcast Entity CBS Cell Broadcast Service CMAS Commercial Mobile Alert Service CMSP Commercial Mobile Service Provider CTCH Common Traffic Channel DRX Discontinuous Reception RNC Radio Node Controller OA&M Operations, Administration, & Maintenance SMS Short Message S
16、ervice XML eXtensible Markup Language 4 FUNCTIONAL ARCHITECTURE & INTERFACES This clause defines the functional architecture and interfaces for the Cell Broadcast Service as defined in 3GPP TS 23.041 Ref 1. The GSM Cell Broadcast architecture is as follows: Figure 1: GSM Cell Broadcast Architecture
17、Similarly, the UMTS Cell Broadcast architecture is as follows: ATIS-0700007 4 Figure 2: UMTS Cell Broadcast Architecture In both the GSM and UMTS architectures for Cell Broadcast, the Cell Broadcast Entity (CBE) could be the CMSP Gateway, a commercial service entity, or an entity which performs both
18、 functions. 4.1 Cell Broadcast Entity (CBE) The Cell Broadcast Entity (CBE) is the source of the Cell Broadcast message that is to be broadcast by the CBC. The CBE could be providing either a commercial information service or an emergency alert service such as CMAS. The CBE provides the CBC with the
19、 geo-target information (e.g., geo-code, polygon, circle) associated with the Cell Broadcast message. The CBC converts this geo-target information into the associated set of cell sites. The CBE provides the CBC with the frequency and duration attributes for the retransmission of the Cell Broadcast m
20、essage. The frequency and duration of the retransmissions is based upon the criticality of the information and the length of its validity. For example, emergency alert messages may have a higher frequency than non-emergency information messages such as sports scores. Additionally, the duration for t
21、he retransmission of an emergency alert message could be the duration of the emergency event. However, traffic congestion alert information has a limit period of validity (e.g., traffic congestion information from the morning commute is not useful for the evening commute), and, therefore, this type
22、of Cell Broadcast message would have a short duration for retransmission. 4.2 Cell Broadcast Center (CBC) The functionality of the CBC is specified in 3GPP TS 23.041 Ref 1. Additional CBC requirements for the support of CMAS are provided in the CMAS via GSM/UMTS Cell Broadcast Specification Ref 9. T
23、he CBC determines the set of cells as defined in sections 5 and 9.3.5 of 3GPP TS 23.041 Ref 1 (e.g., list of cell sites, location areas, service areas) based upon the geo-target information (e.g., geo-code, polygon, circle) provided to the CBC by the CBE. There are no requirements on the accuracy of
24、 geo-targeting. The determination of the set of cells and the accuracy of geo-targeting to the desired broadcast area is operator and implementation specific and may be subject to regulatory requirements. ATIS-0700007 5 The CBC in conjunction with the capabilities of the GSM and UMTS radio networks
25、shall perform retransmissions of the Cell Broadcast message based upon the retransmission information provided by the CBE. 4.3 CBE to CBC Interface According to section 3.1 of 3GPP TS 23.041 Ref 1, the definition of the message transfer on link 1 between the CBE and the CBC is outside the scope of G
26、SM specifications. However, for CMAS, the interface between the CMSP Gateway type of CBE and the CBC for the support of CMAS will be an XML based protocol as defined in the CMAS via GSM/UMTS Cell Broadcast Specification Ref 9. 4.4 CBC to BSC Interface According to section 9.2 of 3GPP TS 23.041 Ref 1
27、, there is no mandatory protocol between the CBC and the BSC specified by GSM, and as such this interface is a vendor specific implementation. In order to implement CMAS and other services, CBCs should be able to interface to all BSCs deployed in the CMSP network via a TCP/IP interface using the pri
28、mitives defined in 3GPP TS 23.041 Ref 1 on physical and logical ports different from OA&M traffic, using the call flows in clause 6.1, Cell Broadcast CMAS Call Flows, of this document. In addition, the CBC to BSC protocol descriptions may be required by CMSPs, test equipment vendors, and monitoring
29、equipment vendors. 4.5 CBC to RNC Interface For the support of Cell Broadcast via UMTS, 3GPP has defined a mandatory protocol between the CBC and RNC in 3GPP TS 25.419 Ref 2. 5 BATTERY LIFE IMPACT ANALYSIS FOR CBS The battery life impacts shown in this clause are based upon GSM technology and are il
30、lustrative only. The battery life impacts for UMTS technology should be similar. Actual battery life impacts may vary based upon factors such as CMSP configurations and mobile device implementations. The impact of the standard Cell Broadcast Service on battery life is unacceptable for applications u
31、sing the Cell Broadcast Service, such as the CMAS application. The guidelines provided in this technical report are based on the requirements identified in CMAS via GSM/UMTS Cell Broadcast Service Ref 9 where it has been specified that Cell Broadcast Service with DRX mode of operation is mandatory f
32、or CMAS. 5.1 Description of Technology Cell Broadcast (CB) is designed for simultaneous delivery of messages to multiple users in a specified area. Cell Broadcast is one-to-many geographically focused service. Cell Broadcast is defined within Phase 1 of the GSM standard in GSM 23.041 Ref 1. A Cell B
33、roadcast message may be from 1 to 15 pages in length. Each page can be up to 93 alphanumeric characters or 82 octets of binary data in length. ATIS-0700007 6 5.2 CB Methods CB: The Cell Broadcast service is designed to minimize the battery usage requirements for a mobile device. A mobile device can
34、read the first part of a CB message and then decide whether or not to read the rest of the message. CB DRX: The network may broadcast Schedule Messages, providing information in advance about the CB messages that will be sent immediately afterwards. The mobile device may use this scheduling informat
35、ion to restrict reception to those messages the customer is interested in receiving. 5.3 Battery Life Calculations when a CMAS Alert is not active 5.3.1 Baseline in a typical case3The broadcast of a message includes the transmission of 4 bursts over the air. In idle mode, a mobile device that receiv
36、es 5 System Information (SI) messages and 30 paging messages in a 30 second time interval will have about 0.269% of activity. This is calculated as shown below: (SI + Pages) * Radio Bursts per message * Radio Burst Duration _ Time Interval (NSI + Npages) * Nradio_bursts* Tframe) / TintervalFormula-1
37、 Where: NSI= 5 (number of SI messages) Npages= 30 (number of paging messages) Nradio_bursts= 4 (number of radio bursts per message) Tframe= 577 sec (time duration of 1 time-slot or 1 radio burst) Tinterval= 30 sec (total time considered) Applying the values to the Formula-1, we will get: (5 + 30) *
38、4 * 0.000577 / 30 = 0.00269 or 0.269% This 0.269% of the mobile device activity in idle mode is used as the baseline in all of the remaining battery life evaluations described in this clause. 3Assumption: Page DRX about 1s. No Neighbor cell activity included. ATIS-0700007 7 5.3.2 Cell Broadcast4The
39、broadcast of a Cell Broadcast message takes 4 consecutive CBCH blocks transmitted within the 8 * 51 TDMA multi-frame. The broadcast of each CBCH block requires the transmission of 4 bursts over the radio. The mobile device operating in a non-DRX mode will have to receive at least one CBCH block once
40、 every 8 * 51 TDMA multi-frame which in turn will increase the idle mode activity of a mobile device by about 45%. The additional activity to receive one CBCH block once every 8 * 51 TDMA multi-frame is calculated as shown below: CBCH Blocks * Radio Bursts per CBCH Block _ Time-slots in a 8*51 TDMA
41、multi-frame NCBCH_ blocks* Nradio_bursts/ Nmulti-frames * Ntdma_frames*NtimeslotsFormula-2 Where: NCBCH_ blocks= 1 (one CBCH block is read in non-DRX mode) Nradio_bursts= 4 (each CBCH block is transmitted in 4 radio bursts over the air) Nmulti-frames= 8 (each of the 8 CBCH Blocks repeat once every 8
42、 multi-frames) Ntdma_frames= 51 (each multi-frame consists of 51 TDMA frames) Ntime-slots= 8 (each TDMA frame consists of 8 time-slots) Applying the values to the Formula-2, we will get (1 * 4) / (8 * 51 * 8) = 4 / 3264 = 0.0012 or 0.12% The additional 0.12% of activity would increase the idle mode
43、activity by about 45% (derived from 0.12/0.269 = 0.45). 5.3.3 Cell Broadcast with DRX With DRX mode of operation, the mobile device will have to receive at a minimum 1 CBCH block of Schedule Message once every Schedule Period. In an idle mode, the mobile device may just have to read one CBCH block o
44、f Schedule Message once every Schedule Period instead of reading at least one CBCH block once every 8 * 51 TDMA multi-frame. The additional device activity in the idle mode to receive one CBCH block of Schedule Message once every Schedule Period will vary based on the duration of the Schedule Period
45、. Therefore, what has been given here is an example. If a Schedule Period consists of 32 8 * 51 TDMA multi-frames (also 4Mobile device reads the first out of four CBCH blocks and decides whether or not to read the rest of the message ATIS-0700007 8 known as 32 Message Slots), then the additional idl
46、e mode mobile device activity to receive one Schedule Message once every 32 Message Slots would be about 0.0038% and is determined as shown below: CBCH Blocks * Radio Bursts per CBCH Block _ Time-slots in a 8*51 TDMA multi-frame * Schedule Period NCBCH_ blocks* Nradio_bursts/ Ntime-slots_multi-frame
47、* NSchedule_PeriodFormula-3 Where: NCBCH_ blocks= 1 (one CBCH block of Schedule Message) Nradio_bursts= 4 (each of CBCH block of a Schedule Message is broadcast using 4 radio bursts). Ntime-slots_multi-frame= 3264 (Number of total time-slots in a 8 * 51 TDMA multi-frame) NSchedule_Period= 32 (Number
48、 of Message Slots in a Schedule Period) Applying the values to the Formula-3, we get: 1 * 4 / 3264 * 32 = 0.0000383 or 0.0038% This 0.0038% of additional activity would increase the mobile device idle mode activity by about 1.4% (derived from 0.0038/0.269 = 1.4%). Note that the smaller the Schedule
49、Period is the larger will be the additional device activity in the idle mode. If the operator has multiple CBS services active (CMAS alerts and commercial broadcast services), CMAS would not introduce any additional power consumption because the mobile device would be receiving these other services and detecting the CBS scheduling info only, not addi
