[移动通讯]【Carrier Aggregation-8】【LTE-A Carrier Aggregation】

前言：

    参考： 《Understanding Carrier Aggregation》

目录：

   1： UE bandwidth class

   2： Channel bandwidths per operating band for CA

   3： E-UTRAN aspects

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一   UE bandwidth class

     

 

      Following table shows Carrier Aggregation Bandwidth Class in terms of total number of RBs used by aggregated carrier.

 

         For example, CA Bandwidth Class 'B' says N_RB,agg <= 100. It means that total aggregated RB should be less than 100. Following shows some example cases which is allowed and not allowed configuration.

Case 1 :

      PCC = 10 Mhz (max 50 RB), SCC = 10 Mhz (max 50 RB).

       It would give max aggregated RB is 50 RB +50 RB which is <= 100. So this is allowed.

Case 2 :

PCC = 10 Mhz (max 50 RB), SCC = 15 Mhz (max 75 RB).

It would give max aggregated RB is 50 RB +75 RB which is >= 100. So this is not allowed.

36.101(Rel 13) - Table 5.6A-1: CA bandwidth classes and corresponding nominal guard bands

bandclass  通过OTA 消息里面的 UE Capability Information message

 

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二  Channel bandwidths per operating band for CA

     UE RACH 后，通过 UE   UL capabilities OTA 进行能力上报，

上下行是独立配置的，对应class 主要有下面三种符号：

例如：

CA_5A-5A configuration： 指示UE可以在band5 频带中接收或发送两个单独的载波

A给出UE带宽类别，指示UE能够在两个频带上的最大100个资源块（RB）（对应于20MHz带宽）。

CA_1C configuration:

1C配置声明: UE可以band1上进行连续两个子载波聚合，最高200个RB

Followings are some more examples without the detailed RRC message.

 

• CA_46C-48E : This is 6CC CA because the class 'C' supports 2CC contiguous band and the class 'D' support 4CC configuous band.
• CA_2A-46A-48E : This is 6CC CA because there are two class 'A' band which support 1 CC for each band and one class 'E' that support 4 CC contiguous band.
• CA_2A-46C-48E : This is 7CC CA because there is one class 'A' which support 1CC, one class 'C' which support 2CC contiguous and one class 'E' that support 4CC contiguous bands.

 < 36.101 Table 5.6A.1-1: E-UTRA CA configurations and bandwidth combination sets defined for intra-band contiguous CA >

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三  E-UTRAN Aspects

      为了支持CA,Release-10引入了PCell（primary cell） 和 SCell（secondary cell）。

      PCell是UE与其通信的主小区，定义为RRC信令与其通信的小区，通过物理上行链路控制信道（PUCCH）的存在来交换消息。对于给定的UE恰好存在一个。一个PCell始终在RRC_CONNECTED模式下活动，而一个或多个SCell 可以是活动的。只有在连接建立后，才能在CONNECTED模式下将附加的SCell配置为提供额外的无线资源。

    所有的PCell 和SCell统称为服务小区。

   对应的子载波分别称为： primary component carrier (PCC) and secondary component carrier (SCC)，

    PCell :

           1 配置对应的PDCCH &PUCCH

           2:  测量和移动管理功能

           3： RACH

          4:  PCell 不能去激活

  SCell 配置PDCCH 根据 UE capabilities, 无PUCCH

      1:   为了降低功耗，MAC 层动态的 activation/deactivation  SCell

    

   下行链路和上行链路中的主小区（PCC）之间的关系在SIB2中通知

。SIB2包含对所有UE通用的无线电资源配置信息。；如上所述，该分配是基于设备的。然而，PCC分配可以是在Handover 中修改。