lte学习总结

srs-BandwidthConfig : 探测参考信号带宽 srs-SubframeConfig :探测参考信号子帧配置

定时器相关另行整理

只有读取了SIB1和SIB2,UE才能驻留小区。

5.1.4 SIB3

CellresectionInfocommon下的Q-Hyst,dB2 表示2 dB cellReselectionServingFreqinfo :异频异系统小区重选信息

S-NonIntraSearch:异频点测量门限(包括测量异系统不同频点的小区),真实值需要*2 threshServingLow:重选到低优先级小区的门限(假设本小区的cellReselectionPriority为2,存在3G的UTRAN的cellReselectionPriority为1,要重选到该小区就得使信号值小于threshServingLow,注:前提需要高优先级上的小区不存在),真实值需要*2

cellReselectionPriority:Inter-RAT下的小区重选时基于优先级的方式实现的,该参数代表了该小区重选时的优先级,异系统的每个RAT的优先级一般是不同的 intraFreqCellReselectionInfo :同频小区重选信息 s-Intrasearch:同频测量门限

allowedMeasBandwidth:允许测量的的最大带宽

The values mbw6, mbw15, mbw25, mbw50, mbw75, mbw100 indicate 6, 15, 25, 50, 75 and 100 resource blocks respectively. presenceAntennaPort1:

The IE PresenceAntennaPort1 is used to indicate whether all the neighbouring cells use Antenna Port 1. When set to TRUE, the UE may assume that at least two cell-specific antenna ports are used in all neighbouring cells.

neighCellConfig:

The IE NeighCellConfig is used to provide the information related to MBSFN and TDD UL/DL configuration of neighbour cells.

Provides information related to MBSFN and TDD UL/DL configuration of neighbour cells of this frequency

00: Not all neighbour cells have the same MBSFN subframe allocation as serving cell

10: The MBSFN subframe allocations of all neighbour cells are identical to or subsets of that in the serving cell

01: No MBSFN subframes are present in all neighbour cells

11: Different UL/DL allocation in neighbouring cells for TDD compared to the serving cell For TDD, 00, 10 and 01 are only used for same UL/DL allocation in neighbouring cells compared to the serving cell.

t-ReselectionEUTRA:重选时延

This specifies the cell reselection timer value TreselectionRAT for E-UTRAN. The parameter can be set per E-UTRAN frequency [3].

5.1.5 SIB4

同频小区列表信息

PhyscellID;物理层小区标识别

Q-offsetcell:用于计算Q-Offset,对于同频小区来说,Qoffsets,n为LOG中读出来的值,但对于异频小区来说,需要Qoffsets,n 加上Qoffsetfrequency。

5.1.6 SIB5

异频重选相关信息

threshX-High: 重选到高优先级门限值,真实值需要*2 threshX-High: 重选到低优先级门限值,真实值需要*2

q-OffsetFreq: 异频重选用于计算q-Offset,等于Qoffsets,n 加上Qoffsetfrequency 部分相同参数见系统消息4

若在SIB5中没有配置cellReselectionPriority 的话,按照协议要求,如果没有配优先级信息,则不测量该频点。(5160:0xf708上报错误 [ID_2012-01-05_3921])

5.2 系统消息的接收

在LTE系统中,MIB存在于PBCH中。由于PBCH的时频资源是固定的,MIB的传输

周期固定为40ms,一个周期内每10ms重传相同的内容。MIB的传输固定在每个无线帧的子帧0的位置上,首次传输位于SFN mod 4=0的无线帧。并且调制编码方式固定,所以只要能准确接收PBCH一个TTI内(40ms)对应的数据,进行解调和译码,就可以得到BCH,进而获得其中的MIB信息。

终端在同网络侧同步后,只是同步上子帧0,或子帧5,所以在收MIB的时候,有可能

会出现收不到的情况,只要再向后延迟5ms即可,在收到MIB后,可以知道当前的无线帧

号。 再通过计算即可实现40ms的同步。

SIB1的传输周期固定为80ms,一个周期内每20ms重传相同内容。SIB1的传输固定在

偶数的无线帧的子帧5,首次传输固定在偶数无线帧的子帧5,首次传输位于SFN mod 8=0的无线帧。

其他的SIB消息,都是SIB1中调度接收的。

如上图所示,SIB2,3,4的接收周期为32个无线帧,假设现在需要接受SIB2,3,4,即第一

个SI块,根据下面的方式确定启动位置 When acquiring an SI message, the UE shall:

1> determine the start of the SI-window for the concerned SI message as follows:

2> for the concerned SI message, determine the number n which corresponds to the order of entry

in

the

list

of

SI

messages

configured

by

schedulingInfoList

in

SystemInformationBlockType1;

2> determine the integer value x = (n – 1)*w, where w is the si-WindowLength;

2> the SI-window starts at the subframe #a, where a = x mod 10, in the radio frame for which SFN mod T = FLOOR(x/10), where T is the si-Periodicity of the concerned SI message;

X=(1-1)*10=0, SFN mod 32 = 0, 也就是说,当该无线帧为32的倍数的值为起始

位置,过了32个无限帧后,开始接收10ms系统消息。没收到,下个周期收。 具体过程,参阅36.331 5.2.3

FLOOR(): 向下取准,FLOOR(9.999)=9

如何确定收到的内容为系统消息呢?物理层在一个一个子帧接收数据的时候,会在

PDCCH上去解相关DCI信息,如果该DCI信息时,SI-RNTI加扰,则将数据直接传给RRC。

Note:MIB和SIB和PCH均采用Transparent MAC格式,MAC不处理,由于又是CCCH

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