HFC network introduction and EPOC requirements from ZSCN

HFC network introduction and

EPOC requirements from ZSCN

EPOC project team, cable working committee of CRTA

Dongqing Zhang - ZSCN

Guangsheng Wu - Huawei

LinZhi Wang - Broadcom

Mr. Yao Yong – Technical committee of CRTA

1 IEEE P802.3bn> EPoC – October

2012 Additional Interim Meeting

Network Overview

• CATV subscriber number – 0.66M

• Bi-directional covered subscriber number –

0.31M

• Bi-directional penetration ratio is improving.

• Basic topology – Fiber to the residential curb ,

with 1 amplifier and centralized distribution

coaxial cable network.

• Accumulated nearly 10,000 records during per

month test within 3years. User CNR is

maintained at more than 44.5dB.



EPoC requirements

• Why EPOC?

– Because FTTH is difficult. Zhongshan cable

network is with fiber-to-the residential curb.

– all IP and service development trends

• Spectrum for EPOC

– 5-65MHz and 900-1200MHz

– 5-65MHz spectrum requires to be co-

existence with HPAV EOC.



Channel test

• Tested at lab environment , with Node+1 topology and

all kinds of tap/splitter/ cable/amplifier

• Selected 2 sites at real network, and tested

noise/interference, etc.

• Mainly tested downstream/upstream Node+1/+0 cable

network characteristics, including signal level, C/N(SNR),

MER, loss - frequency response, group delay, and

calculated micro-reflections accordingly.



Lab test • Topology

H

L

CATV

HPAV

SP

16

SP

16 30m-9

50m-9

10m-5

S

T

B

• Connected 31 STBs, and separately tested parameters under different conditions, e.g. STB connect/disconnect, STB power on/off.

Test point

SP4

amplifier

SP2



Network sites

器件箱处需甲方提供220伏不间断电源。

7C-FB电缆线

放大器

二分配器

6C-FB电缆线

四分支器

终端匹配器

图例:

图例:

1/F

初审制图

图号

图名 4幢楼内系统图

比例设计日期 10.7.01

项目

负责

审定

总体负责

校核

项目

2/F

3/F

4/F

5/F

6/F

7/F

8/F

9/F

10/F

11/F

12/F

13/F

14/F

15/F

16/F

9C-FB电缆线

17/F

18/F

豪逸御华庭有线电视工程

20分配

器件箱（55×35×18cm）

分支分配器箱(25×20×10cm)(建设方提供)

过线盒(建设方提供)

金属线槽(100×50mm)(建设方提供)

PVC管1×1Φ 20(建设方提供)

到各户

到各户

到各户

到各户

19/F

20/F

21/F

22/F

23/F

24/F

25/F

到各户

26/F

到各户

20分配

20分配

16分配

2010082-S4

10分配到商铺

16分配

27/F

28/F

16分配

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

到各户

Test site1

Test site 2 – with HPAV EOC deployed



CNR test results

Under Node+1 scenario: almost all channels C/N≥43dB.

HPAV EOC signals exist at 5-67MHz spectrum.

All test sites are almost the same, without significant interferences exist.

No freq(MHz) mode power C/N(dB) MER(dB) BER

Z01 112.25 PAL-D -32 45

Z02 120.25 PAL-D -30 43

Z03 128.25 PAL-D -29.3 44.9

DS06 168.25 PAL-D -28.2 47.3

DS08 184.25 PAL-D -28 46.3

Z19 331 64QAM -27 43.3 42 0

Z37 482 64QAM -26 43.4 42 0

DS22 538 64QAM -26.7 42.3 40.7 0

DS23 554 64QAM -26.3 43 41 0

DS25 607.25 PAL-D -24 48.6

DS31 751.18 PAL-D -23.8 48.9



Below figure shows noise existed below 55MHz, but it was due to

poor connections on a connector of one splitter-16.

If all connectors are well connected, the false noise will disappear.

Poor connection may cause false

noise/interferences.



The noise floor for both downstream and upstream of N+0 is below

test equipment noise floor (R&S ETL noise floor is about -

165dBm/Hz) , and no significant interferences found.



Lab test with network analyzer -N+1/+0

N+1 S21 N+1 group delay

N+0 S parameters N+0 group delay 10 IEEE P802.3bn> EPoC – October


Real network test –N+0

Test site 1 N+0 S21 Test site 1 N+0 group delay

Test site 2 N+0 S parameters Test site 2 N+0 group delay 11 IEEE P802.3bn> EPoC – October


Micro-reflection analysis of test site1

Node+0

• Because all ports of the network are open, without

75ohm terminal match. There exist serious micro-

reflections especially above 1.0GHz frequency.

0 0.2 0.4 0.6 0.8 1 1.2 1.4-60

-50

-40

-30

-20

-10

0Micro reflections 1.0-1.2G

Time (uSec)

Loss(d

B)

0 0.2 0.4 0.6 0.8 1 1.2 1.4-60

-50

-40

-30

-20

-10

0Micro reflections 1.2-1.4GHz

Time (uSec)

Loss(d

B)



Conclusion

• Under N+0 scenario:

– Given EPOC transmitter power is equal to DVB-C (104dB

μ/8MHz), and the transmission loss is approximately

40dB@860MHz, ≤45dB@1200MHz, and CNU receiver signal

level ≥69dBμ per 8MHz.

– The channel SNR can be higher than 56dB

• Under N+1 scenario: the test SNR is almost higher than

40dB.

• At Zhongshan cable network, with OFDM PHY, the

modulation order can reach 4096QAM

• There are almost no users at two test sites, all network

ports are open, micro-reflections is quite clear.



Thanks!



HFC network introduction and EPOC requirements from ZSCN

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