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CMMB field trail (Phase 1) report 1 /24

Report of Mobile TV Trial in Hong Kong SAR

China Mobile Multimedia Broadcasting (CMMB)

Phase 1

Trial period: 25 November 2008 to 4 December 2008

Version 1.2d Issued date: 12th May 2009 Prepared by: Transmission Network,

Transmission Department Engineering Division

File: CMMB_Trial_Report_P1-2008_V1.2d


Report of CMMB trial (Phase 1) / 24

Acknowledgements

Special thanks are due to the suppliers and organization to loan trial

equipment and provide technical support for the trial below.

• Academy of Broadcasting Planning, China SARFT

• Beijing WiFLARE Technology

• Beijing Thomson Commerce Co., Ltd.



Introduction

The China Mobile Multimedia Broadcasting (CMMB) is China Industry Standard1 developed

by SARFT. The technical specification for receiving and decoding terminal can be found in

released document Part 7: GY/T 220.7-2008. The target recipients include in-car, in-door. The

portable equipments comply with CMMB, include cell phone, USB dongle, SD Dongle, GPS,

in-Laptop, in-PC, in-Car, portable-TV, MP4, and any other portable multimedia terminals. TVB

organize the CMMB field trial with equipment support provided by Beijing WiFLARE

Technology and Beijing Thomson Commerce Co. Ltd and technical support from Academy of

Broadcasting Planning (ABP. This document provides field trial result for the CMMB in Phase

1.

Technical parameter for CMMB technical trial in Hong Kong

Since higher reflection than normal in Hong Kong due to irregular hilly terrain and density

building in urban area, the following technical parameter will be used for the trial test.

QPSK, ½ LDPC, RS (240,192), GI ¼ (LCP)

16QAM, ½ LDPC, RS (240,192), GI ¼ (LCP)

Network Coverage Class

Class A: Outdoor reception

Class B: Indoor reception

Class B1: light indoor

Class B2: deep indoor

Class C: Mobile reception external, outdoor antenna

Class D: Mobile reception inside vehicle

Remark of coverage referring to CMMB specification:

"Good"

If at least 95 % of receiving locations at the edge of the area are covered for portable

reception ( A,B,C & D)

"Acceptable"

If at least 70 % of locations at the edge of the area are covered for portable reception

(Class A,B)

If at least 90 % of receiving locations within it are covered for mobile reception (Class C,

D) 1 China Mobile Multimedia Broadcasting, GY/T 220. 1-2006, Framing Structure, Channel

Coding and Modulation for Broadcasting Channel



CMMB Link Budget – QPSK ½ LDPC

PedestrianClass A

Mobile roof-topClass C

Mobile in-carClass D

IndoorClass B1

IndoorClass B2

Noise FloordBm

-105.2 -105.2 -105.2 -105.2 -105.2

ReceiverNoise FiguredB

5 5 5 5 5

Min C/N in TU6QPSK 1/2

8.2 7.2 7.2 8.2 8.2

Tuner front-end Sensitivity

-92.0 dBm -93.0 dBm -93.0 dBm -92.0 dBm -92.0 dBm

Antenna Gain -5 dBi -2 dBi -5 dBi -5 dBi -5 dBi

Combined Losses 8.5 dB 8.5 dB 15.5 dB 21.4 dB 28.1 dB

Minimum Field Strength Outside

-53.4 dBm/m -57.4 dBm/m -47.4 dBm/m -40.5 dBm/m -33.8 dBm/m

Combined Losses = Penetration Loss + Field Variation + All other Losses

CMMB Link Budget – 16QAM ½ LDPC

PedestrianClass A

Mobile roof-topClass C

Mobile in-carClass D

IndoorClass B1

IndoorClass B2

Noise FloordBm

-105.2 -105.2 -105.2 -105.2 -105.2

ReceiverNoise FiguredB

5 5 5 5 5

Min C/N in TU6QPSK 1/2

14.4 13.4 13.4 14.4 14.4

Tuner front-end Sensitivity

-85.8 dBm -86.8 dBm -86.8 dBm -85.8 dBm -85.8 dBm

Antenna Gain -5 dBi -2 dBi -5 dBi -5 dBi -5 dBi

Combined Losses 8.5 dB 8.5 dB 15.5 dB 21.4 dB 28.1 dB

Minimum Field Strength Outside

-47.2 dBm/m -51.2 dBm/m -41.2 dBm/m -34.3 dBm/m -27.6 dBm/m

Combined Losses = Penetration Loss + Field Variation + All other Losses



Scope of CMMB Trial

1. The objective of the technical trial is to evaluate CMMB reception network coverage

including class A, B, C & D under single station setup at Temple Hill station.

2. Interference measurement between CMMB vs. Analogue PAL-I

Transmitter site and specification

Temple Hill DTT MFN/SFN Main Transmitter station

Location

(HKGRID)

839337 E

824091 N

Antenna Height (meter) 45 m above ground level

Ground level of building 486 m above sea level

COR or TX Antenna 528 m

Maximum E.R.P. 1kW

TX Antenna for DTT trial 4-dipole 3-face 2-stack

Share SFN TX Antenna Ch35 & 37

Antenna direction Face A: 157º

Face B: 227º

Face C: 315 º

Antenna depression Face A: -3º

Face B: -3º

Face C: -3º

Antenna system Gain 7.3 dB

Polarization Horizontal

Test Channel for PN420 Trial Ch47 (678 - 686 MHz)

DTT Transmitter maximum output

RF power

1kW

Coverage of Test Ch 47 same coverage as SFN Ch35 & Ch37



The Phase 1 of CMMB trial includes a single CMMB transmitter being setup at TVB

Transmitter Center in Temple Hill site. The CMMB trial equipment is setup inside equipment

room in 1/F Building No.2. The output of CMMB transmitter is connected to the common

wide-band UHF transmitter antenna system via wide-band input of the 3-channel combiner

unit.

Figure 1: CMMB Trial system setup diagram

Figure 2: Main study areas of CMMB single TX station at Temple Hill site

The main target study areas for CMMB Phase 1 trial include high density urban area in Central



Kowloon, North-west Hong Island and Shatin District. The CMMB Exciter and R&S 1kW

transmitter, CMMB MUX and H.264 Mobile TV encoder locates in equipment rack as shown in

photo below.

Figure 3: Location of CMMB MUX and H.264 Mobile TV Encoder and R&S 1kW CMMB transmitter

Figure 4: Location of CMMB 1kW transmitter and channel combiner



Description of CMMB head-end system setup

CMMB head-end equipment is shown in Figure 5. The test programme includes 5 test

contents. There are two H.264 mobile TV encoders: THALES Argos H.264 TV Encoder and

THOMSON ViBES H.264 Mobile TV encoder. The output of the said encoder use RTP format

connects to the CMMB multiplex. The output the CMMB multiplex provide ASI signal and

connect to the CMMB exciter for driving the R&S 1kW transmitter. The output of the transmitter

connected to the WB input of the RFS channel combiner via a critical mask band pass filter.

The output of the channel combiner connected to the common wide band UHF transmitting

antenna (Normal). The CMMB radiation pattern is same as the SFN Ch35 and Ch37 providing

coverage areas including Shatin district, Kowloon and North Hong Kong Island. The driving

power to the band pass filter is 134 Watts and the maximum E.R.P. is 1kW.

Figure 5: Diagram of CMMB transmitter and head-end equipment at Temple Hill station



Setup of CMMB head-end equipment

Adopt mixed mode of QPSK and 16QAM. Setup parameter refers to Figure 6 below.

Figure 6: Parameters setup of CMMB head-end equipment



3. Description of trial

Equipment list for CMMB trial

No Equipment Name Qty

1 WiFLARE CMMB MUX 1

2 WiFLARE CMMB Exciter 1

3 R&S EX800 1kW DTV Transmitter 1

4 Thales Argos H.264 Encoder 1

5 Thomson ViBES mobile TV Encoder 1

6 RFS Critical mask Ch47 Band Pass Filter 1

7 RFS Coaxial feeders 1

8 RFS UHF wide-band 2-stick & 3-face 1

9 TVB DTT Mobile TV survey vehicle 2

10 WiFLARE CMMB handset terminal 7

11 WiFLARE CMMB Road Test Recorder 1

Table 3: Equipment list for CMMB trial



Test case of CMMB field trial

Test Case Description

1 Condition of coverage under Temple Hill single TX station under QPSK

including service areas: Kowloon, Shatin and north of Hong Kong Island

2 Condition of coverage under Temple Hill single TX station under 16QAM

including service areas: Kowloon, Shatin and north of Hong Kong Island

Table 4: Test case under QPSK and 16QAM

Legend of CMMB packet error and received level

Figure 7: Received level and packet error rate



Measurement result of Class C – Mobile reception external antenna mounted on survey vehicle rooftop

Test case 1: Condition of coverage under Temple Hill single TX station under QPSK including

service areas: Kowloon, Shatin and north of Hong Kong Island

Figure 8: Received level distribution along test routes under QPSK mode

Figure 9: Packet error rate along the test routes under QPSK mode



Received level distribution (QPSK)

Figure 10

PER distribution (QPSK)

Figure 11



Figure 12

Under QPSK mode, > 95% effective reception along the test route can be obtained. From the

trial result, the PER (Packet Error Rate) mainly appear in the low signal strength route. With

reference to the statistic figure, it is note that 56.79% PER is caused by signal strength level

low than -80dBm, 5.13% PER is caused by signal strength lower level in range from -80 to

-75dBm and 1.4% PER is caused by signal strength in range from -75 to –70 dBm.



Test case 2: Condition of coverage under Temple Hill single TX station under 16QAM including service areas: Kowloon, Shatin and north of Hong Kong Island

Figure 13: Received level distribution along test routes under 16QAM mode

Figure 14: Packet error rate along test route under 16QAM mode



Received level distribution (16QAM)

Figure 15

PER distribution (16QAM)

Figure 16



Figure 17

Under 16QAM mode, >94% effective reception along the test route can be obtained. From the

trial result, the PER mainly appear in the low signal strength route. With reference to the PER

statistic figure, it is noted that 63.2% PER is caused by signal strength lower than -80dBm,

10.25% PER is caused by signal strength lower level in range from -80 to -75dBm and 2.39%

PER is caused by low signal strength level range from -75 to -70dBm.



Measurement result of Class B – Indoor reception measurement

Figure 18: Location of Class B indoor reception measurement

The table below summarizes result of CMMB reception trial including 3 different categories:

outdoor, light indoor and deep indoor receiving conditions. The location of Class B CMMB trial

and test result is summarized in Table 8 -3 below.



Table 8- 3 Location and test result for CMMB Class A and Class B

Outdoor Light

Indoor B1

dBm dBm QPSK 16QAM QPSK 16QAM HKGRID E HKGRID N

1 Wan Chai HKECE Expo Drive Entry Information Desk -82 - 5 5 5 5 835819 816139

2 Central Hong Kong Station Airport Express Check in - -61 5 5 5 5 834347 816200

3 Sheung Wan Western Market Time capsule - - 5 4 5 2 833542 816508

4 Sai Wan Praya Kennedy Town COSCO Hotel Lobby -71 - 5 2 5 1 831648 816304

5 Kowloon West Element The Rink -61 -68 5 6 5 5 834823 818268

6 Tai Kok Tsui Olympian City 2 Atrium -71 -82 5 5 5 5 834698 819736

7 Tsing Yi Ferry Terminus Outside - - 5 0 nil nil 829324 823583

8 Tsing Yi Maritime Square L1 to Villa Esplanada Exit -61 - 5 0 3 0 829202 824476

9 Sha Tin Green Leaves Garden House of Bread -75 - 5 5 5 5 838642 826847

10 Sha Tin New Town Plaza G/F TownHall Exit -54 - 5 5 5 5 837515 826918

11 Sha Tin MTR Station Ticket Centre - - 5 5 5 1 837439 826976

12 Ma Liu Shui Science Park Photonic Centre G/F -62 -77 5 5 5 0 840124 831626

13 Ma Liu Shui Science Park ASTRI 5/F - -87 5 5 5 0 840124 831626

14 Kowloon Bay Mega Box G/F -62 -78 5 5 5 5 839514 820129

15 Yau Tong MTR Station Ko Fai Road Exit A -61 -87 5 5 4 2 842532 817595

16 Tsim Sha Tsui Harbour City Ocean Terminal 1/F -62 -80 5 5 5 2 835399 817327

Grade of reception:

5: Excellent 4: Good 3: Satisfory

2: Marginal 1: Poor 0: Failure

DistrictNoHKGRID of Place

Class B1 Reception Grade (light indoor

B1)

Class A Reception Grade (Outdoor)PlaceLocation



Class D: CMMB reception test inside MTR in East Rail Line

The reception test inside MTR east rail line was carried out mainly for the stations between Tai

Wai to University because these stations are within the coverage area of Temple Hill station.

The reception test result is shown in table 8-5 with grade point shown in Table 8-4.

Table 8- 1 Grade Point of the test

Figure 19: CMMB reception test inside MTR in east rail line

Grade Point Definition

5 Excellent

4 Good

3 Satisfactory

2 Marginal

1 Poor

0 Failure

Note:

Effective stations for

CMMB reception test

inside MTR train is

between stations of

Tai Wai to/from



Table 8- 2 Test results

Class D: CMMB reception test inside vehicle

The reception test inside test vehicle using CMMB hand set (K-Touch V958) has been

performed along the same test route of Class C. The evaluation is by TOV without recording of

signal strength and PER because lack of measurement equipment in the test. In general, the

Class D reception inside vehicle is satisfactory in most of the test routes with strong field

strength condition.

Interference measurement between CMMB vs. Analogue PAL-I

The interference inspection result indicates that analogue channel 48 from Mt. Nicholson was

free from adjacent channel interference from the CMMB Ch47 radiated from Temple Hill

station.

Station Grade Station Grade

Tai Wai (Platform) 1 Sheung Shui (Platform) Failed

Tai Wai Sha Tin 5 Fanling Sheung Shui Failed

Sha Tin (Platform) 1 Fanling (Platform) Failed

Sha Tin Fo Tan 5 Tai Wo Fanling Failed

Fo Tan (Platform) 1 Tai Wo (Platform) Failed

Fo Tan University 5 Tai Po Market Tai Wo Failed

University (Platform) 1 Tai Po Market (Platform) Failed

University Tai Po Market Failed University Tai Po Market Failed

Tai Po Market (Platform) Failed University (Platform) 1

Tai Po Market Tai Wo Failed Fo Tan University 5

Tai Wo (Platform) Failed Fo Tan (Platform) 1

Tai Wo Fanling Failed Sha Tin Fo Tan 5

Fanling (Platform) Failed Sha Tin (Platform) 1

Fanling Sheung Shui Failed Tai Wai Sha Tin 5

Sheung Shui (Platform) Failed Tai Wai (Platform) 1



Notes of Class C measurement

The Class C measurement is setup by means of a tuned dipole antenna mounted on the

survey vehicle in horizontal polarization as shown in Figure 20 & 21 below.

Figure 20: The survey vehicle (left) is used to conduct the Class C reception trial

Figure 21: The outlook of the tuned dipole receiving antenna is used for Class C reception trial

The output of the tuned dipole antenna with calibrated coaxial cable is connected directly to

the mobile road test recorder (see Figure 22) to obtain measurement data along different test

routes.



Figure 22: Road test recorder for CMMB mobile TV reception

It is note that

1. tuned dipole antenna is used with the Road Test Recorder;

2. the dipole antenna output is connected to the Road Test Recorder directly without

calibration to simulate as CMMB hand held terminal device, and

3. The measurement signal strength is recorded for analysis of the signal strength

distribution along different test route conditions.

Notes on further CMMB trials

With reference to the measurement data and scope of trial in Phase 1, further technical trial for

CMMB will take following key issues into account to do trial planning.

1. CMMB reception performance in Hong Kong under configuration of SFN, and

2. CMMB reception performance under different guard interval under SFN configuration.



Conclusions

In accordance to the measurement result of CMMB trial, in condition of single transmitter

station setup at Temple Hill station, the performance of CMMB coverage in different reception

classes; A, B, C and D have been conducted and present in this report.

Based on the measurement result, further field trial will be arranged under SFN configuration

in order to evaluate the coverage performance under number of SFN stations.

In general, CMMB technology performs one of the mobile TV standards with capability in

supporting portable and mobile digital TV services in Hong Kong SAR.

*** END ***

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