MFBI介绍（mfbs）

MFBI:Multi-Frequency Band Indicator

指不同的Band中有重合的frequency，重点关注下面IE信息，详细解释见3GPP协议。

• freqBandIndicator
• multiBandInfoList
• freqBandIndicatorPriority-r12
• freqBandPriorityAdjustment-r12

按3GPP协议标准

• 如果终端支持freqBandPriorityAdjustment，网络的SIB1消息中freqBandIndicatorPriority为true，multiBandInfoList具有最高优先级。
• 如果终端支持freqBandPriorityAdjustment，网络的SIB1消息中没有freqBandIndicatorPriority，freqBandIndicator具有最高优先级。
• 如果终端不支持freqBandPriorityAdjustment，freqBandIndicator具有最高优先级。

multiBandInfoList（多频带信息列表）

MFBI指射频小区存在于多个频段中。

引入MFBI是为了避免重叠小区所在的两个频段之间发生漫游问题。

例如，LTE B26是LTE B5的MFBI频段，支持B26的UE应能够漫游到B5并驻留在重叠小区上。支持B5的UE也能漫游到B26并驻留在重叠小区上。因此，引入了multiBandInfoList，即将B26加入multiBandInfoList，B5为freqBandIndicator，终端优先注册B5小区。

frequencBandPriorityAdjustment/freqBandIndicatorPriority

CMCC引入了freqBandIndicatorPriority-r12和freqBandPriorityAdjustment-r12，因为在支持LTE B38和B41的终端上，有一些CA配置方面问题。

网络设置freqBandIndicator为B38，multiBandInfoList中包含B41。因此，UE驻留在LTE B38的小区上。

当网络需要终端配置LTE CA_B41-B39时，就会导致终端需要从B38 handover到B41。为了避免这种切换，引入了freqBandIndicatorPriority，指示小区属于多频段，不需要做Handover。

3GPP协议定义

multiBandInfoList

A list of additional frequency band indicators, as defined in TS 36.101 [42], table 5.5-1, that the cell belongs to. If the UE supports the frequency band in thefreqBandIndicator field it shall apply that frequency band. Otherwise, the UE shall apply the first listed band which it supports in the multiBandInfoList field. If E-UTRAN includes multiBandInfoList-v9e0 it includes the same number of entries, and listed in the same order, as in multiBandInfoList (i.e. without suffix). See Annex D for more descriptions. The UE shall ignore the rule defined in this field description if freqBandIndicatorPriority is present and supported by the UE.

freqBandIndicatorPriority

If the field is present and supported by the UE, the UE shall prioritize the frequency bands in themultiBandInfoList field in decreasing priority order. Only if the UE does not support any of the frequency band in multiBandInfoList, the UE shall use the value in freqBandIndicator field. Otherwise, the UE applies frequency band according to the rules defined in multiBandInfoList. NOTE 2.

freqBandPriorityAdjustment

Indicates whether the UE supports the prioritization of frequency bands inmultiBandInfoList over the band in freqBandIndicator as defined by freqBandIndicatorPriority-r12.