medalas china presentation v4.0

TETRA 网络优化专家Copyright © by Medalas Consulting Ltd 2010. All Rights

Reserved. www.medalas.com

Maximising Your TETRA Network Investment

使您的 TETRA 网络投资发挥最大作用



About Us关于我们 Hello, my name is Andy Fleet, I am Medalas Chief Executive Officer 大家好，我是 Medalas 的 CEO Andy Fleet Medalas are a UK based consultancy specialising in TETRA Network Validation &

Optimisation from 1998 Medalas 是一家英国咨询公司，成立于 1998 年，专门从事 TETRA 网络验证

及优化 Medalas were deeply involved in optimising the UK TETRA network for UK Police

Forces during network deployment and in-life operation Medalas 在英国的网络建设与日常运营中参与了大量的为英国警察部队优化

TETRA 网络的工作 Medalas assist TETRA Network operators, users and system integrators in more

than 30 countries around the world. Medalas 为全球三十多个国家的 TETRA 网络运营商，用户及系统集成商提供

帮助

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Market Focus – Public Safety市场核心—公共安全 Our company is motivated by a duty to ensure that Public Safety professionals who put

themselves in danger to protect us receive the best communications service possible 这样一种使命感激励着 Medalas 团队：确保那些为了我们的利益而置身险境的公共安

全专业人员最大可能地获得最好的通信服务

Making sure that when it has to work.... It works first time!

当需要它工作时，确保它能在第一时间运行

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Consultancy Services咨询服务

Technical Consultancy 技术咨询

Requirements Definition 需求定义

System Design 系统设计

RF Planning RF 规划

Validation Strategies 验证策略

Optimisation Strategies 优化策略

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Optimisation Services优化服务

RF Propagation Surveys RF 传播调查 Test & Acceptance 测试与验收 Coverage Measurements 覆盖范围测量 Performance Optimisation 性能优化 Training & Workshops 培训及研讨会 Application Development 应用开发 System Audits 系统审计

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Optimisation Tools优化工具

Walk Test Systems 步行测试系统

Drive Test Systems 开车路测系统

Analysis & Optimisation Systems

分析及优化系统

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TETRA Digital Radio Systems provide: TETRA 数字无线电系统可提供：

Unparalleled Voice Quality & Legibility 无与伦比的语音质量和易读性

Near Instant Communications (sub-300 milliseconds) 接近及时的通信（低于 300 毫秒）

Secure Encrypted Communications 安全的加密通信

Rich Functionality for Public Safety Users 针对公共安全用户的丰富功能

However, they are complex and advanced systems that demand expert validation, optimisation & monitoring

虽然如此，这些复杂先进的系统仍然需要专业的验证，优化及监测

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TETRA Optimisation – Why?为什么需要优化 TETRA ？



TETRA – Moving from Cell to CellTETRA- 由小区到小区的移动

TETRA is a cellular system and to get the best performance for the user, the way the radio handset moves from cell to cell must be optimised so that it always uses the strongest radio signal – as shown below

TETRA 是蜂窝式无线通信系统，可使用户获得最好的性能，只有对这种无线电对讲机从小区到小区移动的方式进行优化，才能使其始终获得最强的无线电信号—如下图所示：

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Attached to Cell 1连接到小区 1Strong Signal很强的信号

Good Performance很好的性能





CELL 1小区

1

CELL 2小区

2

CELL 3小区

3



Cell Dragging – A Typical Problem小区驻留 - 典型问题

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“Cell Dragging” is the term used to describe the situation where a radio handset is not receiving the correct information for the cells in the local area

小区驻留是指无线电对讲机无法在区域内为小区接收到正确的信息 It means that under some circumstances a radio handset will “drag” a cell past the point

at which it could get better service from another cell if it had the correct information 也就是说，在某些情况下，无线电对讲机接收到错误的信息时，仍旧驻留在原

来的小区，而不能从另一个小区里得到更好的服务 The result is that the radio handset may be in an area with very good coverage, but still

delivers very poor performance 结果就是，无线电对讲机可能在一个非常好的覆盖区域内，但是仍旧显示很差的性能 This a problem of network configuration optimisation, but because all the user experiences

is the radio handset they blame the handset 其实这是网络配置优化的问题，但是因为所有的用户看到的只是无线电对讲机，所以他们只是责怪对讲机设备。

In our experience more than 50% of all “coverage problems” reported can be caused by configuration optimisation problems which can result in cell dragging

以我们的经验来看，超过 50% 的覆盖范围问题是由优化配置问题引起的，这些问题会导致小区驻留问题的发生



TETRA – Cell DraggingTETRA 小区驻留

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When a radio handset experiences cell dragging, performance to the user degrades, even though it may be in an area of very strong signal

当无线电对讲机遭遇小区驻留时，即使在信号非常强的区域，性能仍会降低



Still Attached to Cell 1仍然连接到小区 1

Medium Signal中等的信号强度

Medium Performance中等的性能

Still Attached to Cell 1仍然连接到小区 1

Poor Signal较差的信号强度Poor Performance较差的性能

CELL 1小区

1

CELL 2小区

2

CELL 3小区

3



An Example of Cell Dragging小区驻留实例

Description 说明

In this example “cell dragging” was caused by poor network configuration and resulted in very poor service in an area which had very good radio signals

在这个例子中，“小区驻留”由较差的网络配置引起，并且在无线电信号很强的区域内导致较差的服务

The configuration errors included: 配置错误包括：

A neighbour cell that was not being transmitted 相邻小区信息没被传送 A move to the wrong cell for the radio handset’s location 无线电对讲机选择了错误的小区 A cell configured with no neighbour cells 无相邻小区配置

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Cell Dragging - 1

12

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm

-110 to -119 dBm

In this example a drive test measured the same location twice from different directions – from one direction receiving very good service, and from the other direction receiving very poor service – very confusing to users在这一例子中，通过路测从不同的方向对同一地点进行了两次测试——一个方向接收到了非常好的服务，而另一个方向接收到了非常差的服务——用户对此非常困惑



Cell Dragging - 2

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Cell 1

Cell 2

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm

-110 to -119 dBmCell 4Cell 3

The problem started here, with the handset attached to cell 1问题由连接到小区 1 的对讲机设备开始



Cell Dragging - 3

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Cell 1

Cell 2

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm


At this point the handset moves to cell 2 – a good choice在这一地点，对讲机移动到了小区 2——非常好的选择



Cell Dragging - 4

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Cell 1

Cell 2

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm


But the problems start here, because cell 2 should be broadcasting cell 5 as a neighbour cell, and in this example was not – very bad但是问题由此开始，因为小区 2 应该广播 cell5 为相邻小区，但是在这一例子中却没有发生——非常糟糕



Cell Dragging - 5

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Cell 1

Cell 2

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm


This means that the radio handset is now travelling towards cell 5, but has no knowledge of its existence – it relies on the network to give it correct information about the cells around it也就是说，无线电对讲机现在向小区 5 移动，但是却没有意识到它的存在——这依赖于网络能够向它提供关于周围小区的正确信息



Cell Dragging - 6

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Cell 1

Cell 2

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm


At this point the radio handset is getting a poor signal from cell 2 so decides to move back to cell 1 – moving to cell that the handset is travelling away from is often a sign of a problem在这一地点，无线电对讲机从小区 2 接收到了很差的信号，因此决定回到小区 1——向无线电设备正在离开的小区移动，这经常是出现问题的信号



Cell Dragging - 7

18

Cell 1

Cell 2

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm


Because the decision to move back to cell 1 is a bad one, after 30 seconds the radio handset has to move cell again – this time it makes another bad decision due to the lack of information from the network – it moves to a cell that is more than 30Km away – it moves to cell 3

因为返回小区 1 是一个错误的决定，所以 30 秒之后，无线电对讲机必须再一次离开这个小区——这一次，它会因为缺少由网络而来的信息而做出另一个错误的决定——它移动到了另一个 30千米之外的小区里——它移动到了小区 3



Cell Dragging - 8

19

Cell 1

Cell 2

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm


Now on cell 3 – the radio handset it being told about neighbour cells for cell 3 – which are not correct for the real location of the radio handset现在在小区 3 中——无线电对讲机被告知小区 3 为相邻小区——这对无线电对讲机的真实地点来说是不正确的



Cell Dragging - 9

20

Cell 1

Cell 2

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm


At this point service delivered to the user is seriously reduced for several kilometres, the signal strength less than -100dBm as shown by the red and purple circles, and experienced failed calls and poor speech quality在这一地点，几千公里内，为用户提供的服务质量严重下降，如红色及紫色圆圈所示，信号强度低于 -100dBm ，通话故障并且语音质量很差



Cell Dragging - 10

21

Cell 1

Cell 2

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm


The radio handset then makes another attempt to find good service and this time moves to cell 4 as a result of losing service and scanning all frequencies由于失去了服务，在对所有的频率进行扫描后，无线电对讲机又一次尝试寻找良好的服务，这一次它移动到小区 4



Cell Dragging - 11

22

Cell 1

Cell 2

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm


The final problem is with cell 4 – it should be broadcasting cell 5 as a neighbour, but is not transmitting any neighbour cell information at all最后的问题与小区 4 有关——原本它应广播小区 5 为相邻小区，但是却没有发送任何相邻小区的信息



Cell Dragging - 12

23

Cell 1

Cell 2

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm


This means that the only way for the handset to move from this cell is to reach the point where service is lost completely and a new scan can be performed to find a usable cell也就是说，对讲机从这一小区移出的唯一途径是到达一个完全丧失了服务并且可以通过新的扫描找到一个有可用小区的地点



Cell Dragging - 13

24

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm

-110 to -119 dBm

The result of this sequence of poor configuration optimisation is that at the same point on this road users receive very different service depending upon the direction of travel对较差的配置进行一系列优化的结果是，在一条路上相同的地点，用户接收到不同的服务取决于移动的方向不同



Cell Dragging - 14

25

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm

-110 to -119 dBm

Travelling from south to north on this road at this point when on the correct cell for the location – the radio handset is receiving a very strong signal of -44dBm从南向北移动到这条路的这个地点，当它在这个地点的正确的小区时——无线电对讲机可以接收到高达 -44dBm 信号强度的信号



Cell Dragging - 15

26

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm

-110 to -119 dBm

Travelling from west to east on this road at this point when on the incorrect cell for the location – the radio handset is receiving a very poor signal of -100dBm从西向东移动到这条路的这个地点时，当它在这个地点的不正确的小区时——无线电对讲机会接收到信号强度为 -100dBm 的非常差的信号



Cell Dragging - 16

27

Cell 5

0 to -9 dBm

-10 to -19 dBm

-20 to -29 dBm

-30 to -39 dBm

-40 to -49 dBm

-50 to -59 dBm

-60 to -69 dBm

-70 to -79 dBm

-80 to -89 dBm

-90 to -99 dBm

-100 to -109 dBm

-110 to -119 dBm

The result – sometimes very good service and sometimes very bad service – very confusing for users – they almost always report it as a “coverage problem” when in fact it is a simple matter of optimisation结果是——有的时候服务质量非常好而有的时候服务质量非常差——用户对此非常困惑——他们几乎总是会将其报告为覆盖范围问题，而事实上，这只是一个简单的优化问题



Thank you

谢谢

[email protected]

[email protected]

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