WCDMA项目面试问题
1. 项目经验介绍（注重时间段）
Tell me something about your WCDMA projects (pay attention to the period)
2. XXX项目主要都是做些什么，你负责哪些工作？
What are you responsible for in XXX project?
3. 是否做过数据分析？数据分析都分析哪些指标？关注哪些参数？
Have you ever done data analyszing? And what KPI we should pay attention to?
4. 有没有做过天线调整？都做些什么？
Have you ever done antenna tuning? And what to do?
机械下倾角、电子下倾角、方位角调整
E-Tilt tuning/M-Tilt tuning/Azimuth tuning
天线接反调整
Tuning of Antenna wrongly connected
5. 勘站时需注意什么事项？勘站需要勘察什么数据？
What would you pay attention to when doing site survey? And why do site survey?
安全第一
Safty must come first
工具列表
序号
工具
1
数码相机 digital camera
2
手持式GPS portable GPS
3
车载逆变器inverter
4
指南针compass
5
倾角仪clinometer
6
测距仪DME
7
调天线工具tools for antenna tuning
8
皮卷尺measuring tape
9
高性能电脑computer
勘站数据
1) Longitude、Latitude——GPS
2) Tilt（倾斜角）——倾角仪
3) Antenna Height（天线高度）——GPS
4) Azimuth（方位角）——指南针
5) Picture(每30度角一个照片)反映周边情况——数码相机
6) Antenna type
6. 都用过哪些测试软件、优化软件？
What testing and optimization tools have you used?
TI 9.1
RA
Sony Ericsson Z750(MS)
Scanner
TV
TCPU
7. WCDMA如何定义为导频污染？
How to define pilot pollution in WCDMA netwrok?
WCDMA是个自干扰系统，但是过度的干扰也会带来诸多负面效应，导频污染就是其中最明显的一个。对于WCDMA系统，简单来说，导频污染就是指某测试点接收的小区导频信号差别不大（都很强或都很弱），而没有主导频。从测试手机上来看，其表现形式通常是接收的导频功率足够好，但各小区Ec/Io都较弱。目前大部分WCDMA设备支持的最大激活集数目是3，也就是说，如果不同小区相近的Ec/Io数目超过了3个，就可以看成是对激活集里面3个无线链路的干扰
WCDMA radio network is self-infection one, too much interference will lead to bad result, such as pilot pollution. As for WCMDA system, pilot pollution is that in one place, UE can receive many signals, but no dominant one. We can see from the testing phone, there are several signals from different cells with good RSCP, but poor Ec/No. Now most of the WCDMA equipment can surpport 3 Active Sets at most, that’s to say, if UE in one place can receive more than 3 signals with near Ec/No, the forth signal can be taken as a pilot polluter.
8. 测试中常见的事件有哪些，发现了什么问题，怎么解决，如HSUPA速率低、室内信号外泄、室外信号入侵、掉话、切换失败等如何分析和解决？
What events usually occur when do testing? How to solve? Such as low HSUPA speed rate/inbuilding signal leaking/drop call/handover failure and so on, how to analyze and solve them.
HSUPA速率低主要原因：
Cause of low HSUPA speed rate:
IUB接口物理带宽受限，分配给HSUPA的AAL2PATH带宽不足。
IUB interface physical bandwidth is limited, that’s, AAL2PATH bandwidth that assigned to HSUPA is not enough
小区码资源受限
Cell code resource is restricted
上行干扰大RTWP比较高
Too much UL interference, high RTWP
室内信号外泄：
Inbuilding signal leaking:
在天线口增加衰减器，减低天线输出功率
Add attenuator to the antenna to decline output power
调整室内天线位置
Re-locate the antenna
室外信号入侵：
Outdoor signal intruding:
调整室外天线的方向角或下倾角
Tune the cell downtilt or tune the azimuth
降低室外信号的导频功率
Decline the outdoor cell PrimayCpichpower
切换失败处理方法：
Dealing with handover failure:
采取以上RF调整后，增加室内和室外小区的邻区关系
add neighbor relation
9. W的基本原理（如所用频段、带宽、码片速率是多少）？
WCDMA basic theroy
WCDMA频段：上行1920-1980 MHz，下行2110-2170 MHz
WCDMA frequncy band: UL 1920-1980 MHz, DL 2110-2170 MHz
带宽 5 MHz
Bandwidth: 5 MHz
码片速率 3.84 MHz/s
Code chip rate: 3.84 MHz/s
10. 2/3G互操作切换的信令流程
Signaling process of 2/3G interoperability
PS域切换信令流程
PS handover signaling process
11. 小区重选的算法
Arithmetic of cell seletion
协议25.304中小区选择S准则的定义如下：
Srxlev>0且Squal>0  其中，Squal=Qqualmeas-Qqualmin
Srxlev=Qrxlevmeas-Qrxlevmin-Pcompensation
Qqualmeas即为小区质量的测量值CPICH的Ec/N0。
Qrxlevmeas为CPICH的RSCP；
Qrxlevmin为当前小区所需最低导频信号接收功率；
Pcompensation= max(UE_TXPWR_MAX_RACH – P_MAX, 0)
12. 主叫的信令流程
Call signaling process
RRC连接建立流程-信令建立流程（主叫）-鉴权和安全模式流程-呼叫建立流程（主叫）-RAB建立流程-呼叫释放流程（主叫）-RRC连接释放流程
RRC connection setup process-signaling setup process-Authentication and safty mode pr
ocess-call setup process-RAB set up process-call release process-RRC release process
1. 是否了解HSDPA和HSUPA吗？
Do you know something about HSDPA and HSUPA?
HSDPA是高速下行分组接入，理论峰值为14.4Mbps，采用16QAM调制方式
HSDPA is high-speed downlink packet access, with peak value 14.4 Mbps. Modulation mode is 16 QAM
HSUPA是高速上行分组接入，理论峰值为5.76Mbps
HSUPA is high-speed uplink packet access, with peak value 5.76 Mbps
13. WCDMA有哪些逻辑信道和物理信道？
Logical channel and physical channel in WCDMA systme
公共物理信道包括：PSCH  SSCH  PCPICH  PCCPCH  PRACH  SCCPCH  AICH  PI
CH
Common physical channel: PSCH  SSCH  PCPICH  PCCPCH  PRACH  SCCPCH  AICH  PICH
专用物理信道包括DPCCH  DPDCHhtmlradio添加切换事件
Dedicated Physical Channel: DPCCH DPCH
H业务物理信道：HS-PDSCH  HS-SCCH  HS-DPCCH
H service physical channel: HS-PDSCH  HS-SCCH  HS-DPCCH
控制逻辑信道：BCCH  PCCH  DCCH  CCCH
Control logical channel: BCCH  PCCH  DCCH  CCCH
业务逻辑信道： DTCH  CTCH
Service logical channel: DTCH  CTCH
14. 1a/1b/1c/1d/2a /2d/2f分别是什么？

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