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标题: 请教LTE终端接收信号功率计算的问题 [查看完整版帖子] [打印本页]

时间: 2012-6-20 15:07

作者: atpcat 标题: 请教LTE终端接收信号功率计算的问题

如题，比如调度给终端一个RB，那么请问计算终端接收信号功率时，是应该用基站总功率(43dBm)-路损(dB)，还是应该用一个RB上的功率（比如20M小区，每个RB功率（43-20）=23dBm)-路损？期待大家答复，谢谢。

时间: 2012-6-20 18:06

作者: jeffyko

you should use
received level = 23 + antenna gain - any feeder loss - shadow fading - penetration loss - path loss

时间: 2012-6-24 16:01

作者: jamebong007

为什么要把总功率平均到每个PRB上？又没有使用MU-MIMO，不能使用最大的功率吗？

原帖由 jeffyko 于 2012-6-20 18:06 发表
you should use
received level = 23 + antenna gain - any feeder loss - shadow fading - penetration loss - path loss

时间: 2012-6-24 18:45

作者: atpcat

原帖由 jamebong007 于 2012-6-24 16:01 发表
为什么要把总功率平均到每个PRB上？又没有使用MU-MIMO，不能使用最大的功率吗？

我也没搞明白。。。等明白人解答

时间: 2012-6-25 09:45

作者: jeffyko

firstly, PDSCH EPRE(power per RE per antenna port) can be set based on CRS EPRE, and according to 36.213, the difference between PDSCH EPRE and CRS EPRE is decided by a RRC configurable parameter: P_A.
Generally, CRS EPRE is fixed and broadcasted by SIB2. and P_A is UE specific, and the value range is [-6, -4.77, -3, -1.77, 0, 1, 2, 3], so at maximum PDSCH EPRE = CRS EPRE + 3dB. The value range of CRS EPRE is -60~50dBm.
In the extreme, we can set CRS EPRE and P_A to proper value to allow a single user to use as much power as possible.
But normal practices is that it is a multi-user network, and CRS EPRE is generally set to the average power (that's 20W(per antenna port) - 10*log10(1200)=12dBm), and P_A may be to 0dB. In this case, PDSCH power per PRB is 12+0+3(two branchs tranmission)+10*log10(12) = 25dBm

[ 本帖最后由 jeffyko 于 2012-6-25 09:50 编辑 ]

时间: 2012-6-25 13:15

作者: jamebong007

谢谢你的讲解！有一点还想问一下，20W(per antenna port) - 10*log10(1200)=12dBm里，10*log10(1200）一项是什么含义？
还有PDSCH power per PRB 在计算的时候，有3dB的“two branchs tranmission”这有是什么啊？
请不吝赐教，多谢多谢！

原帖由 jeffyko 于 2012-6-25 09:45 发表
firstly, PDSCH EPRE(power per RE per antenna port) can be set based on CRS EPRE, and according to 36.213, the difference between PDSCH EPRE and CRS EPRE is decided by a RRC configurable parameter: P_ ...

时间: 2012-6-26 15:59

作者: flyearth

20W(per antenna port) - 10*log10(1200)=12dBm是对数域的计算公式
实际等效于总功率/1200，也就是每个RE上的平均功率
12+10*log10(12)就是每个PRB上的平均功率

时间: 2012-6-28 20:51

作者: jeffyko

3dB是因为eNB有2个发射通道

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