单选题(GSM理论).doc

GSM理论题
1. 关于TDMA帧的说法不正确的是A
A.一个复帧包含7个TDMA帧
B.一个超帧可以包含26个复帧
C.一个超高帧包含51个超帧
D.一个超高帧包含10608个TDMA帧
TCH的复帧有26个TDMA帧，而用于映射BCH和CCH的复帧有52个TDMA帧 。

2. 2206支持传输接口有BCD
A.50ohm
B.75ohm
C.100ohm
D.120ohm

3. 对于BA表的描述，下列哪个是错误的？ A
A、立即更新方法只用于空闲模式表而默认方法只用于激活模式。
B、空闲模式表可取较长而激活模式表尽量短。
C、激活模式表最好不要超出16个。
D、空闲模式表用于移动台的空闲模式而激活模式表及于移动台的激活模式。
立即更新方法和默认方法都可以用于空闲模式和激活模式

4. 我们使用最多的从BTS到BSC的传输接口是C
A、T1 1.5 Mbit/s, 100欧姆，内部同步
B、T1 1.5 Mbit/s, 100欧姆，PCM同步
C、E1 2 Mbit/s, 75欧姆，PCM同步
D、E1 2 Mbit/s, 120欧姆，PCM同步

5. 在开启下行DTX功能时，TCH和SDCCH下行链路分别采用什么测量集？ B
A、fullset、subset
B、subset、fullset
C、subset、subset
D、fullset、fullset
??
6. 主同步码的用途是 A
A、时隙同步
B、帧同步
C、解PN码组
D、解PN码

7. 下面哪一个信道是与SCH一起复用的？ A
A、PCCPCH
B、SCCPCH
C、RACH
D、CPICH

8. 由于小区空闲模式覆盖区与激活模式覆盖区不相等时，将会出现下列哪个现象？ B
A、小区的内切数与外切数出现明显的差别。
B、如果空闲模式覆盖区小时出现外切数增加。
C、如果空闲模式覆盖区大时该小区的呼叫建立数将会较大。
D、以上三个答案都不对。
空闲模式覆盖区小时，则MS可能在其激活模式的覆盖区内使用其他小区信号起呼，然后就会向该小区进行切换，所以内切数会增加。

9. 下列关于质差切换，哪种说法是错误的？ C
A、质差切换的区域是由参数BQOFFSET来决定的。
B、质差切换是一种非正常的切换类型。
C、质差切换是一种紧急切换，其的优先等级高于正常切换。
D、质差切换只能发生在离基站较远的小区边缘。

10. 以下关于小区负荷分担（Cell Load Sharing）的描述，哪项是错误的？ D
A、小区负荷分担可以分流小区话务负荷。
B、小区负荷分担只能小区间切换缓冲区域内的话务。
C、小区负荷不能分担到外部小区。
D、可通过加大CRH来增大小区缓冲区的方法来增大负荷分担的作用。
可通过加大RHYST来增大小区缓冲区的方法来增大负荷分担的作用

11. Are the UL signal strength measurements used in the locating algorithm? E
A、Yes, of course.
B、No, not at all.
C、Yes, but it is used only to check if conditions for intra-cell and urgency handovers are fulfille
D、No, it is used only for power control of the mobile.
E、Yes, but it is used only to check if the conditions for intra-cell handover are fulfille
对于上行信号的测量，只对服务小区的进行测量，它是用于小区内切及用于MS功控！！

12. What is the basic ranking in the Ericsson1 locating algorithm based on? A
A、Relative signal strength
B、Absolute signal strength
C、Minimum signal strength
D、Sufficient signal strength
E、Quality

13. What is BQOFFSET used for? E
A、It is used to trigger a bad quality urgency condition.
B、It is used as a signal strength offset to penalize cells after a badquality urgency handover.
C、It is used to offset the trigger conditions for a bad quality urgency handover.
D、It is used to prevent a new handover attempt in a cell after handover failure.
E、It is used to restrict the distance to a candidate cell, if a bad quality urgency condition is triggered

10. Which logical channel must be dimensioned for each cell when considering the call set-up frequency? C
A、SACCH
B、FCCH
C、SDCCH
D、SCH
E、BCCH

14. 以下关于切换的描述，哪个是错的？ B
A、从高层的小区切向低层小区的切换具有最高优先等级。
B、当移动台在通话质差很严重时会出现质差切换。
C、在设置正常的系统中，大部分切换是使移动台切往通话质量较好的小区。
D、两次切换间的最小时间隔间是可以定义的。
小区内切换和紧急质差切换都是由质量差引起的切换，小区内切换比质差紧急切换的优先等级高，这意味着如果一个小区内切换和一个质差紧急切换被同时执行时将会优先尝试一个小区内切换。

15. 对于辅助网络功能的说明，哪项是错误的？ A
A、负荷分担功能可以使话务忙的小区上HYST区域外的话务分担到较空闲的小区上。
B、小区分层结构可以使一些小区具有较高的优先等级。
C、小区范围扩展功能可使小区的最大覆盖范围从35公里扩展到72公里。
D、分配到其它小区功能可提高设备的利用率。
负荷分担功能可以使话务忙的小区上HYST区域外的话务分担到较空闲的相邻小区上。

16. 下列关于跳频功能的描述，哪个是不正确的？ C
A、跳频将会改善多径衰落对系统造成的负面影响。
B、频率越多，跳频的作用越大。
C、跳频的规律都是采用随机跳频的，HSN对跳频影响不大。
D、如果RBS200基站的部分TX-BUS出现阻塞，开启跳频将会出现小区自动闭塞现象。

17. 下列关于小区内切换的说明，哪种是错误的？ D
A、小区内切换能够改善系统内的短期干扰对通话质量的影响。
B、小区内切换的作用在开启跳频的情况下将会减弱。
C、在开启跳频的系统中，突然出现频繁的内切换，可能是由于部分载波出现故障。
D、小区内切换可以发生在整个小区的覆盖范围内。

18. 关于一层小区的描述，下列哪种说法是不正确的？ D
A、第一层小区不论在何种情况下都有最优先的等级。
B、当移动台发生差质时将会优先切往一层小区。
C、当移动台在一层小区通话时，如果周围没有相邻的一层小区，将会在一定区域内失去选优切换的功能。
D、一层小区只用于室内覆盖。
一层小区可用于其他地方覆盖。

19. 关于分配到其他小区功能，下列哪种说法是错误的？ C
A、它包括指配到较好的小区和指配到劣质小区两种情况
B、指配到较好小区是指配时出现相邻小区比当前小区更好。
C、当服务小区在指配时TCH全忙，这时肯定会出现指配到劣质小区情况。
D、这个功能由参数ASSOC来激活。
当服务小区在指配时TCH全忙，这时可以出现指配到较好小区的情况。

20. 下列关于负荷分担功能的描述，哪种说法是错误的？ D
A、负荷分担比例可以通过参数RHYST来调整。
B、当RHYST=100时容易出现乒乓切换。
C、加大KHYST值能够增强负荷分担功能所起的作用。
D、加大KHYST值容易出现乒乓切换。
加大KHYST值不会导致容易出现乒乓切换。

17. 用作GMSC询问HLR的GT为： D
A、HLR ADDRESS B、IMSI C、MGT D、MSISDN

18. 在局间切换当中，切换号码是在哪一个路由分析： B
GRI B、MHOC C、MTB D、MHIC

21. 以下关于分配到其他小区（Assignment to Another Cell）的描述，哪项是错误的？B
A、分配到其他小区功能是应用在分配TCH时的。
B、分配到其他小区是指移动台的空闲状态时通过运算自身的定位算法选出一个比当前小区更好或更差的小区用于建立呼叫。
C、分配到更好小区可以提高通话质量。
D、分配到更差小区可以充分利用网络资源，提高接通率。
分配到其他小区是在MS通话状态下进行的。

22. 以下关于无线链路超时的描述，哪项是正确的？D
A、下行中断通话是由参数RLINKT决定的，并由MS业控制接执行的；而上行中断通话是由参数RLINKUP决定的，并由BSC来控制执行的。
B、下行中断通话是由参数RLINKUP决定的，并由BSC业控制执行的；而上行中断通话是由参数RLINKT决定的，并由MS来控制执行的。
C、下行中断通话是由参数RLINKT决定的，并由BSC业控制执行的；而上行中断通话是由参数RLINKUP决定的，并由MS来控制执行的。
D、下行中断通话是由参数RLINKT决定的，而上行中断通话是由参数RLNKUP决定的，都由BSC来控制执行的。

23. 以下哪种情况容易出现C/R值偏高？C
A、将基站建在离建筑物近的地方
B、将基站建在离建筑物远的地方，天线背向建筑物且具有较高的前背比
C、将基站建在湖泊区附近的地方
D、将基站建在平原地区
（由于湖面反射）

24. 以下哪种功能不是由BTS单独进行的？B
A、跳频
B、功率控制
C、不连续发射
D、以上都不是
（BTS和手机都可以进行功率控制）

25. 基站采用FCOMB，则要求相邻频点间隔至少为 B
A、400kHz B、600kHz C、200kHz D、25kHz

26. BSTXPWR=43，BSPWRMIN=20时，动态功率的最大调整范围是： D
A、30dBm B、62dBm C、13dBm D、23dBm
27. 对于信号强度的惩罚，下列哪个是错误的？ B
在定位算法过程，惩罚包括LOC及HCS两种。 B、LOC惩罚只包括质差切换惩罚和超TA切换惩罚。 C、HCS惩罚是发生在二层小区向一层小区切换的情况。 D、当切换失败、低质量紧急切换和过大时间提前（Timing Advance）紧急切换定位算法会执行相应的惩罚。
（LOC惩罚包括切换失败、质差切换惩罚和超TA切换惩罚）
28. 列哪些因素能够影响到系统的切换性能？ C
A、频率及BSIC规划、逻辑信道的映射方案及BA表的长度。 B、多层小区间的门限值及逻辑信道的映射方案。 C、频率及BSIC规划、多层小区间的门限值及BA表的长度。 D、上面三个答案都不对。
29. OL与UL小区间的切换由下列哪组参数决定的？ C
A、BQOFFSET与AWOFFSET B、QLIMDL与QLIMUL C、LOL与TAOL D、LOL与TALIM
30. 以下关于快速移动的移动台，下列描述哪个是错的？ B
可以通过调整参数SSLENDL来调整其动态功率控制速度使其适应无线环境的要求。 B、如果发现在动态功率调整区域内出现切换不成功现象可以调整参数QCOMPDL及参数LCOMPDL来解决。 C、如果发现在动态功率调整区域内出现弱信号情况，可以通过增大参数SSDESDL来增大该区域的信号强度。 D、如果发现在动态功率调整区域内出现质差的现象，可以通过调整参数QDESDL改善。
（如果发现在动态功率调整区域内出现切换不成功现象可以调整参数QLEN及参数SSLEN来解决）
31. 下列几种说法，哪种是错误的？ A
上行链路的切换决定于基站接收到的上行信号强度的大小。 B、下行链路的切换决定于移动台接收到的下行信号强度的大小。 C、上、下行链路的切换决定于移动台接收到的下行信号强度的大小。 D、对于相邻小区，上下行链路的切换决定于移动台接收到的下行信号强度的大小，而对于服务小区来说上下行链路的切换决定于移动台接收到的下行信号强度的大小。
（上行链路的切换决定于移动台接收到的下行信号强度的大小）
32. 分配到其它小区的特性由两个参数来决定,一个是BSC,另一个是CELL,下列哪一个是关于小区的 B
A、ASSOC B、AW
33. MAIO是为了减小频率干扰的，分为人工配置和缺省配置。哪一种复用形式建议采用人工配置的： C
A、1/3 B、3/9 C、1/1
34. 如果下列链路的LEVTHR=90，LEVHYST=3，移动台将可能在下列哪个电平上切出一层小区？ D
A、-65dBm B、-75dBm C、-85dBm D、-95dBm
（由一层小区切到二层小区的电平门限为：<LEVTHR- LEVHYST）
35. 小区选择C1算法跟以下那个因素有关? C
A、Rxlev_min(n) B、MS_Txpwr_Max C、Rxlev_Access_Min D、BS_Txpwr_Max
36. 为避免因过多跨越LAC的小区重选而造成的SDCCH的阻塞,我们将与该小区有切换关系且与之LAC不同的相邻小区 B 提高
A、T3212 B、Cell_Reselect_Hysteresis C、Cell_Reselect_offset
37. Which protocol performs the addressing for circuit related signaling?
A、MTP B、SCCP C、ISUP
38. Calculate the processor capacity in terms of calls/s when the traffic load is 72% and the load per call is 25ms.
A、28,8 calls/s B、31,4 calls/s C、33,8 calls/s
39. Which of these different “dropped call rates” gives a “subscriber perceived” drop rate? B
A、Dropped TCH connections of the total number of TCH connections B、Dropped calls of the total number of calls terminated in the cell C、Erlang minutes per dropped TCH connection D、Average call drops experienced during one hour talk time E.All of these
40. What is added to the MS sensitivity level to obtain the required signal strength, SSreq? C
A、Rayleigh fading margin B、Rayleigh fading margin and interference margin C、Rayleigh fading margin, interference margin, and body loss D、Rayleigh fading margin and body loss E.Interference margin and body loss
41. What is the most common value of the hysteresis used when estimating margins for log-normal fading? A
A、3 dB B、5dB C、6dB D、8dB E.10dB
42. AGBLK must be set to a non-zero value (that is = 1 in Ericsson’s GSM system), if: A
A、Cell broadcast is used in a cell with a non-combined configuration. B、Cell broadcast is used in a cell with a combined configuration. C、System information, type 4, is sent on the BCCH. D、System information, type 5, is sent on the BCCH. E.MFRMS=2 or MFRMS=9
43. Which is the most important factor for determining the paging capacity in the BTS? D
MFRMS (controls the number of paging groups) B、AGBLK (reserves a paging block for access grant) C、Paging strategy (for example, second page in the MSC service area or in the LA) D、Combined or non-combined mapping E.The use of cell broadcast
44. What is the parameter TINIT used for? A
A、To set the initial value of the timer that inhibits handover after a change of channel. B、To set the initial value of the timer that controls the measurement events of the mobile. C、To set the initial value of the timer that controls if handover during signaling is allowed or not. D、To set the initial value of the timer that controls if handover to another BSC is allowed or not. E.To set the initial value of the timer that controls the filtering process.
45. The purpose of ramping is to avoid handover decisions to a new neighbor based on only a few samples. What is a common parameter setting for macro cells? E
SSRAMPSI=10 and SSRAMPSD=20 B、SSRAMPSI=20 and SSRAMPSD=10 C、SSRAMPSI=10 and SSRAMPSD=10 D、SSRAMPSI=5 and SSRAMPSD=2 E、SSRAMPSI=2 and SSRAMPSD=5
(To avoid the handover too fast based on a few samples, SSRAMPSI, SSRAMPSD would be set to be more, SSRAMPSI is Ramping length Signal strength, signalling, SSRAMPSD is Ramping length Signal strength, speech/data)
46. What is the difference between BSTXPWR at the “preferred reference point” and the reported signal strength in the mobile? C
A、Path loss B、Path loss, minus antenna gain C、Path loss, minus antenna gain, plus feeder loss D、Path loss, minus antenna gain plus feeder and combiner losses E.There is no difference
47. What is the purpose of setting BSRXSUFF to –150 dBm and MSRXSUFF to 0 dBm in all cells? D
A、To make sure that the uplink signal strength influences the basic ranking. B、To enable path loss ranking. C、To ensure that the signal strength on the uplink is always sufficient. D、To obtain an absolute signal strength ranking. E.To disable path loss ranking.
48. When may the merry-go-round effect occur? C
A、If TINIT has a low value B、If the hysteresis is too small C、If the offset is non-zero D、If PSSTEMP is set to a low value E.If PTIMTEMP is set to a low value
49. What is TRHYST used for? B
A、It modifies the sufficient level condition for neighboring cells. B、It modifies the sufficient level condition for neighboring cells and the serving cell. C、It is used to move the L-L border. D、It is used to move the K-K border. E.It is used to move both the K-K and the L-L borders.
50. Cells in the basic ranking list are divided into categories. How many categories are there, if the serving cell is considered as a category of its own? B (E)
A、2 B、3 C、8 D、10 E.11
(1bo,1bu,1wo,1wu,2bo,2bu,2wo,2wu,3b,3w,S, total categories is 11)
51. The Figure below shows the outcome from basic ranking. Assuming all cells except D and H fulfil band and layer thresholds, what cells should be prioritized and in what order? ?? E
A、A, B, F, G, E, and C B、G, E, B, A, C, and F C、G, E, B, and A D、B, A, F, G, E, and C E.A, B, E, and G
52. The idle mobile derives an entity called C1. How is C1 used? A
C1 for a particular cell must be larger than zero for a mobile to be allowed to camp on that cell. B、C1 is a quality check and if not fulfilled, the idle mobile must try another cell to camp on. C、C1 and BSIC are reported to the serving cell, at least, once every five seconds to enable network controlled cell re-selection. D、At cell re-selection, the cell with the largest derived C1 is chosen to camp on. E.C1 is set to yes, if both CB and CBQ are low.
(C1>0)
53. What is CRH used for? C
A、It is used in combination with ACCMIN to cater for a layered cell structure in a dual band network. B、It is used as a temporary offset to make a cell appear better during cell re-selection. C、It is used as a hysteresis between location area borders. D、It is used in a limited service state to enable emergency calls. E.It is the maximum number of repeated unsuccessful access attempts.
54. What is one of the differences between the phase 1 and phase 2 establishment causes? D
A、Phase 2 establishment causes distinguish between answer to paging and call re-establishment. B、Phase 2 establishment causes distinguish between MS originated call and answer to paging. C、Phase 2 establishment causes distinguish between location updating and answer to paging. D、Phase 2 establishment causes distinguish between MS originated calls and SMS. E.Phase 2 establishment causes distinguish between call re-establishment and SMS.
55. Which of the criteria below is not influenced by the value of CHAP? A (B) ???
Prioritizing of different users or not. B、Immediate assignment on the TCH allowed or not. C、TCH or SDCCH first. D、Overlaid subcell as a last resort or not. E.Phase 1 or phase 2 mobiles.
(chap is Channel allocation profile)
56. Why can BTS power control be used to increase the capacity (that is, tightening the frequency re.use in the network)? E
A、It increases the sensitivity of the mobile B、It increases the number of mobiles with high C/I. C、The power consumption in the radio base station is reduceD、 D、It reduces the risk of MS receiver saturation. E.It reduces the number of mobiles with low C/I.
57. If the path loss compensation parameter, LCOMPDL, is set to ten, the down regulation in the BTS output power, due to path loss compensation, is limited to: A
A、6 dB B、10 dB C、12 dB D、20 dB E.30 dB
58. Assume that there are 12 frequencies (f1-f12) in the hopping frequency set. What default MAIO values are allocated to the first seven TRXs in the cell”? C
A、0, 1, 2, 3, 4, 5, and 6 B、1, 2, 3, 4, 5, 6, and 7 C、0, 2, 4, 6, 8, 10, and 1 D、1, 3, 5, 7, 9, 11, and 0 E.0, 3, 6, 9, 1, 4, and 7
59. What is the result from field measurements of coverage compared with: B
A、The design criterion B、The required signal strength C、The required signal strength, plus the log-normal fading margin D、The design criterion, minus the body loss E.The design criterion multiplied by a “probability of coverage” factor
60. What are event and level counters? A
A、It is the name of the software counters that are stepped in function blocks outside the STS (in RPs and CPs). B、It is the name of the counters of alternative A when they are stored/used in the STS later. C、It is the name of the counters of alternative B when they are stored/used in OSS later. D、Both A and B are correct. E.Both B and C are correct.
61. What is not taken into account when deriving SQI? E
BER B、FER C、HO events D、Speech coder E.Timing advance
(SQI did not consider Timing Advance)
62. What is the normal event that leads to an abnormal disconnection and stepping of the drop counter? B
A、Failed decoding of speech frames B、Failed decoding of SACCH frames C、Excessive BER D、Poor signal strength E.Excessive timing advance
63. If a call is dropped during excessive TA, bad quality and poor signal strength, which cause counter will step? C
A、SS drop counter B、Q drop counter C