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标题: 考考你, LTE知多少? (25题) [查看完整版帖子] [打印本页]

时间: 2009-12-13 14:51

作者: logicaman 标题: 考考你, LTE知多少? (25题)

Q.1) Which type of cell provides the best level of service for average subscribers?
A. Acceptable cell B. Barred Cell C. Reserved Cell D. Suitable Cell
Q.2) Which UE categories support 64QAM on the uplink?
A. Only category 5 B. Categories 3, 4 and 5 C. None of them D. All of them
Q.3) What types of handover are supported in LTE?
A. Hard handover only B. Hard and soft handovers C. Hard, soft and softer handovers D. Handover is not supported
Q.4) Why is a Cyclic Prefix required in OFDMA?
A. To ensure the symbol time is an integer number B. To help overcome multipath and inter-symbol interference C. To maintain orthogonality D. To make OFDMA scalable
Q.5) What does the DC subcarrier indicate?
A. The identity of the cell B. The antenna configuration C. The center of the OFDM channel D. The format of the data channel
Q.6) What processing step combines multiple OFDM subcarriers into a single signal for transmission?
A. FFT B. IFFT C. RF Combining D. Channel Mapping
Q.7) What is the minimum amount of RF spectrum needed for an FDD LTE radio channel?
A. 1.4 MHz B. 2.8 MHz C. 5 MHz D. 20 MHz
Q.8) In MIMO, which factor has the greatest influence on data rates?
A. The size of the antenna B. The height of the antenna C. The number of transmit antennas D. The number of receive antennas
Q.9) What organization is responsible for developing LTE standards?
A. UMTS B. 3GPP C. 3GPP2 D. ISO
Q.10) Which channel indicates the number of symbols used by the PDCCH?
A. PHICH B. PDCCH C. PBCH D. PCFICH
Q.11) How often can resources be allocated to a UE?
A. Every symbol B. Every slot C. Every subframe D. Every frame
Q.12) What property of OFDMA systems allows adjacent subcarriers to be used without interference?
A. Orthogonality B. Orthodoxy C. Octagonality D. Originality
Q.13) With the normal Cyclic Prefix, how many symbols are contained in 1 frame?
A. 7 B. 12 C. 20 D. 140
Q.14) What is the largest channel bandwidth a UE is required to support in LTE?
A. 20 MHz B. 10 MHz C. 5 MHz D. 1.4 MHz
Q.15) In OFDM, what is the relationship between the subcarrier spacing f and the symbol time t?
A. There is no fixed relation B. f = t C. f x t = 2048 D. f = 1/t
Q.16) What is the PBCH scrambled with?
A. The physical cell ID B. The current frame number C. The UE's C-RNTI D. The PBCH is not scrambled
Q.17) Why is the Cyclic Prefix a copy of the tail end of the symbol?
A. It ensures a continuous time domain signal B. It maintains an integer number of cycles C. It reduces the Peak-to-Average Power Ratio (PAPR) D. It increases the useful symbol time
Q.18) In LTE, what is the benefit of PAPR reduction in the uplink?
A. Improved uplink coverage B. Lower UE power consumption C. Reduced equalizer complexity D. All of the above
Q.19) Approximately what portion of a subframe in a 1.4 MHz channel is available for carrying the PDSCH?
A. 1/2 B. 1/4 C. 3/4 D. 1/6
Q.20) If the UE detects primary synchronization sequence x and secondary synchronization sequence y, what is the physical cell ID?
A. The physical cell ID cannot be determined from the synchronization signals B. x+y C. 3x+y D. x+3y
Q.21) Which RLC mode adds the least amount of delay to user traffic?
A. Acknowledged Mode (AM) B. Unacknowledged Mode (UM) C. Transparent Mode (TM) D. Low Latency Mode (LM) Q.22) What coding scheme is used for the DL-SCH and UL-SCH?
A. 1/3 tail-biting convolutional code B. 1/3 turbo code C. Variable-rate block code D. 1/3 repetition code
Q.23) How much bandwidth is required to transmit the primary and secondary synchronization signals?
A. 1.4 MHz B. 1.08 MHz C. 930 kHz D. up to 20 MHz
Q.24) What is the length of the shortest possible PDCCH, in bits?
A. 72 B. 144 C. 288 D. 576
Q.25) With PRACH configuration 14, what are the odds that two UE's will collide during their random accesses?
A. 1 in 10 B. 1 in 64 C. 1 in 640 D. It is impossible to collide on the PRACH

时间: 2009-12-14 17:00

作者: airwjd

答案呢？

时间: 2009-12-14 20:06

作者: lance26

强烈要求上答案～～

时间: 2009-12-15 14:27

作者: logicaman

顶的人不多,看来大部分学友都会.
上不上答案也无所谓了.

时间: 2009-12-15 16:59

作者: outlawsong

有始有终吗，lZ还是把答案放上来的好

时间: 2009-12-15 22:36

作者: jxy

还是把答案发出来吧

时间: 2009-12-17 09:49

作者: maikxie

看来多数网友都是E盲啊！Q不就是问题吗？A不就是答案吗，不知你们还要什么答案？

时间: 2009-12-17 14:08

作者: logicaman

d,a,a,b,c
b,b,c,b,d
c,a,d,a,d
a,a,d,a,d
c,b,b,a,c

时间: 2009-12-18 09:14

作者: lxw68240485

看不懂啊，太难了

时间: 2009-12-18 09:51

作者: t.vv@msn.com

7楼真逗啊

时间: 2009-12-18 10:59

作者: 飞扬跋扈

7楼太雷人了

时间: 2009-12-18 14:16

作者: DONGKAKA

LTE(Long Term Evolution,长期演进)项目是3G的演进，始于2004年3GPP的多伦多会议。LTE并非人们普遍误解的4G技术，而是3G与4G技术之间的一个过渡，是3.9G的全球标准,它改进并增强了3G的空中接入技术，采用OFDM和MIMO作为其无线网络演进的唯一标准。在20MHz频谱带宽下能够提供下行326Mbit/s与上行86Mbit/s的峰值速率。改善了小区边缘用户的性能，提高小区容量和降低系统延迟。

时间: 2009-12-19 00:38

作者: leo86 标题: 回复 7# 的帖子

七楼的顶你了！这都能想的出来！

时间: 2009-12-20 23:27

作者: radiocom

汗，我也就是刚及格的水平，本以为对lte了解不少，虽然还没真正搞过

时间: 2009-12-21 09:43

作者: zjqq_cm111

考英语？？

时间: 2009-12-21 15:28

作者: helloadolf

哈哈，七楼开的这个玩笑很有力度啊，

时间: 2009-12-22 14:49

作者: wsswq

N年前考试的时候就这么蒙过

时间: 2009-12-26 00:10

作者: jxy

很久没熬夜了，来看看

时间: 2010-1-4 14:04

作者: jackychen12056

答案好像有误吧？
Q.7) What is the minimum amount of RF spectrum needed for an FDD LTE radio channel?
A. 1.4 MHz B. 2.8 MHz C. 5 MHz D. 20 MHz
答案是B？最小系统带宽应该是1.4M吧。。不管TDD还是FDD。。。
Q.17) Why is the Cyclic Prefix a copy of the tail end of the symbol?
A. It ensures a continuous time domain signal B. It maintains an integer number of cycles C. It reduces the Peak-to-Average Power Ratio (PAPR) D. It increases the useful symbol time
我觉得应该选B。。FFT积分周期内各子载波周期成整数倍关系才能保证保证子载波的正交性。答案怎么是A呢？
Q.19) Approximately what portion of a subframe in a 1.4 MHz channel is available for carrying the PDSCH?
A. 1/2 B. 1/4 C. 3/4 D. 1/6
控制域大小4符号。。10/14＝5/7大约3/4的样子。。选B。。考虑RS开销选A。。

时间: 2010-1-8 20:44

作者: bluefeet

赞同19楼的解释。

时间: 2010-1-9 12:43

作者: qiusuo365

答案都有了，还要求答案

时间: 2010-1-19 00:00

作者: wjunny

答案是对的

时间: 2010-1-26 15:55

作者: rfc3344

Q.1) Which type of cell provides the best level of service for average subscribers?
A. Acceptable cell B. Barred Cell C. Reserved Cell D. Suitable Cell

no idea

Q.2) Which UE categories support 64QAM on the uplink?
A. Only category 5 B. Categories 3, 4 and 5 C. None of them D. All of them

A

Q.3) What types of handover are supported in LTE?
A. Hard handover only B. Hard and soft handovers C. Hard, soft and softer handovers D. Handover is not supported

A

Q.4) Why is a Cyclic Prefix required in OFDMA?
A. To ensure the symbol time is an integer number B. To help overcome multipath and inter-symbol interference C. To maintain orthogonality D. To make OFDMA scalable

B

Q.5) What does the DC subcarrier indicate?
A. The identity of the cell B. The antenna configuration C. The center of the OFDM channel D. The format of the data channel

C

Q.6) What processing step combines multiple OFDM subcarriers into a single signal for transmission?
A. FFT B. IFFT C. RF Combining D. Channel Mapping

B

Q.7) What is the minimum amount of RF spectrum needed for an FDD LTE radio channel?
A. 1.4 MHz B. 2.8 MHz C. 5 MHz D. 20 MHz

A

Q.8) In MIMO, which factor has the greatest influence on data rates?
A. The size of the antenna B. The height of the antenna C. The number of transmit antennas D. The number of receive antennas

B

Q.9) What organization is responsible for developing LTE standards?
A. UMTS B. 3GPP C. 3GPP2 D. ISO

B

Q.10) Which channel indicates the number of symbols used by the PDCCH?
A. PHICH B. PDCCH C. PBCH D. PCFICH

D

Q.11) How often can resources be allocated to a UE?
A. Every symbol B. Every slot C. Every subframe D. Every frame

C

Q.12) What property of OFDMA systems allows adjacent subcarriers to be used without interference?
A. Orthogonality B. Orthodoxy C. Octagonality D. Originality

A

Q.13) With the normal Cyclic Prefix, how many symbols are contained in 1 frame?
A. 7 B. 12 C. 20 D. 140

D

Q.14) What is the largest channel bandwidth a UE is required to support in LTE?
A. 20 MHz B. 10 MHz C. 5 MHz D. 1.4 MHz

A

Q.15) In OFDM, what is the relationship between the subcarrier spacing f and the symbol time t?
A. There is no fixed relation B. f = t C. f x t = 2048 D. f = 1/t

D

Q.16) What is the PBCH scrambled with?
A. The physical cell ID B. The current frame number C. The UE's C-RNTI D. The PBCH is not scrambled

A

Q.17) Why is the Cyclic Prefix a copy of the tail end of the symbol?
A. It ensures a continuous time domain signal B. It maintains an integer number of cycles C. It reduces the Peak-to-Average
Power Ratio (PAPR) D. It increases the useful symbol time

A

Q.18) In LTE, what is the benefit of PAPR reduction in the uplink?
A. Improved uplink coverage B. Lower UE power consumption C. Reduced equalizer complexity D. All of the above

B

Q.19) Approximately what portion of a subframe in a 1.4 MHz channel is available for carrying the PDSCH?
A. 1/2 B. 1/4 C. 3/4 D. 1/6

A

Q.20) If the UE detects primary synchronization sequence x and secondary synchronization sequence y, what is the physical cell ID?
A. The physical cell ID cannot be determined from the synchronization signals B. x+y C. 3x+y D. x+3y

C or D, not sure

Q.21) Which RLC mode adds the least amount of delay to user traffic?
A. Acknowledged Mode (AM) B. Unacknowledged Mode (UM) C. Transparent Mode (TM) D. Low Latency Mode (LM)

C

Q.22) What coding
scheme is used for the DL-SCH and UL-SCH?
A. 1/3 tail-biting convolutional code B. 1/3 turbo code C. Variable-rate block code D. 1/3 repetition code

B

Q.23) How much bandwidth is required to transmit the primary and secondary synchronization signals?
A. 1.4 MHz B. 1.08 MHz C. 930 kHz D. up to 20 MHz

B

Q.24) What is the length of the shortest possible PDCCH, in bits?
A. 72 B. 144 C. 288 D. 576

A

Q.25) With PRACH configuration 14, what are the odds that two UE's will collide during their random accesses?
A. 1 in 10 B. 1 in 64 C. 1 in 640 D. It is impossible to collide on the PRACH

B

不知道答对了多少

时间: 2010-1-26 16:00

作者: rfc3344 标题: 回复 19# 的帖子

Q.17) Why is the Cyclic Prefix a copy of the tail end of the symbol?
A. It ensures a continuous time domain signal B. It maintains an integer number of cycles C. It reduces the Peak-to-Average Power Ratio (PAPR) D. It increases the useful symbol time
我觉得应该选B。。FFT积分周期内各子载波周期成整数倍关系才能保证保证子载波的正交性。答案怎么是A呢？

在下的看法：题目本身是问为什么CP是从尾巴里copy过来。在相关接受的时候，CP是要被扔掉的，没有被包括在FFT积分周期内的。（当然是没有TA的完美情况），Symbol的长度能够保证正交
答案A是对的，确实为了保证时域上的连续性

时间: 2010-2-5 22:12

作者: h345026039

怎么都是英文的

时间: 2010-5-14 16:39

作者: shohokuooo

原帖由 DONGKAKA 于 2009-12-18 14:16 发表
LTE(Long Term Evolution,长期演进)项目是3G的演进，始于2004年3GPP的多伦多会议。LTE并非人们普遍误解的4G技术，而是3G与4G技术之间的一个过渡，是3.9G的全球标准,它改进并增强了3G的空中接入技术，采用OFDM和MIMO作 ...

这是什么玩意的回帖啊，这都给分，无语了，LTE版真混乱！

时间: 2010-5-15 09:34

作者: stavats 标题: 回复 24# 的帖子

正解。

时间: 2010-5-15 09:35

作者: stavats

又减我经验和金钱，每次在LTE版讨论技术都是遇到差的随机事件，太阳的～～～～～～～
无一例外。

时间: 2010-5-15 09:36

作者: stavats 标题: 再次太阳

什么掉WC花8大洋。。。。。。

时间: 2010-5-15 09:37

作者: stavats 标题: 又被举报卖烟

又是扣钱扣经验。。。。。

时间: 2010-5-26 21:42

作者: atombjut

了解70%

时间: 2010-8-25 10:05

作者: juvefans1983 标题: 回复 19# 的帖子

Q.7) What is the minimum amount of RF spectrum needed for an FDD LTE radio channel?
A. 1.4 MHz B. 2.8 MHz C. 5 MHz D. 20 MHz
答案是B？最小系统带宽应该是1.4M吧。。不管TDD还是FDD。。。

一开始我也觉得是A，后来仔细看了下，觉得还是B对，注意amount，是要上下行加起来的，2.8 MHz是正解。

时间: 2010-8-25 10:11

作者: juvefans1983

请教
Q.16) What is the PBCH scrambled with?
这句问的是什么，The physical cell ID不是在syn RS中传的么？和PBCH有什么关系？
多谢！

时间: 2010-8-25 10:15

作者: juvefans1983

Q.25) With PRACH configuration 14, what are the odds that two UE's will collide during their random accesses?
A. 1 in 10 B. 1 in 64 C. 1 in 640 D. It is impossible to collide on the PRACH
这道题不知道怎么算的？

时间: 2010-8-25 10:43

作者: rc5

在20MHz频谱带宽下能够提供下行326Mbit/s与上行86Mbit/s的峰值速率
********************
这是是用了MIMO 4*4吧, 要不然频谱效率都 16 bit/hz/s了

时间: 2010-12-18 19:05

作者: tomend 标题: 求解？

时间: 2011-1-16 00:26

作者: heweifu1884 标题: 回复 19# 的帖子

另外10的答案是 D

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