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Television Broadcasts Limited
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 2 / 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.
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 3 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 4 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 5 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 6 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 7 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 8 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 9 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 10 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 11 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 12 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 13 / 24
Received level distribution (QPSK)
Figure 10
PER distribution (QPSK)
Figure 11
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 14 / 24
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.
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 15 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 16 / 24
Received level distribution (16QAM)
Figure 15
PER distribution (16QAM)
Figure 16
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 17 / 24
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.
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 18 / 24
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.
Television Broadcasts Limited
CMMB field trail (Phase 1) report 19 /24
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
Television Broadcasts Limited
CMMB field trail (Phase 1) report 20 /24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 21 / 24
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
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 22 / 24
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.
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 23 / 24
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.
Television Broadcasts Limited
Report of CMMB trial (Phase 1) Page 24 / 24
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 ***