:lol

这是LTE Signaling - Troubleshouting and Optimization提到的。抱歉我没说清楚，一开始粘贴的是1.10.7.1的内容。
4.4.1.5 Paging Failures
The analysis of paging failures requires a distinct workflow rather than just a simple KPI. Due to the
tracking area concept of the E-UTRAN, the last known location of a handset that does not respond
to paging messages sent by the MME can be more tightly encircled. In a network with one cell
representing a single tracking area the UE will be paged in a few cells only, whereas in 2G and 3G
RAN paging messages are typically sent to all cells of a particular Location Area Code (LAC) – a few
hundred cells compared to a few dozen in the E-UTRAN. However, a paging failure ratio KPI on cell
aggregation level will always have a questionable value due to the fact that a UE can only camp in a
single cell and, hence, from most cells to where the paging was sent there will be no paging response.
It therefore makes sense to store the subscriber ID of UEs that have not answered the paging and
investigate what may have happened to them before the paging failure and where they may have gone
to. The most likely reasons for paging failures are as follows:
• The UE is defective and went out of order without being able to detach from the network.
• The UE while in IDLE mode performed a new cell (re)selection and is camping now on a 3G or
2G cell without informing the network properly about the new location that is geographically the
same as before, but covered by a different RAT.
Possible root causes of paging failures to be investigated according to these symptoms are:
• defective handsets;
• insufficient coverage;
• wrong settings for broadcast cell (re)selection parameters like S0 criteria.
252 LTE Signaling, Troubleshooting and Optimization
Considering the interworking between 3G and 4G radio access, it must be highlighted that it
will become very important to monitor both radio access networks to get rapid updates of UEs
toggling between the different RATs. This requirement is driven by the fact that the handsets in
UTRA CELL_PCH and URA_PCH are allowed to perform cell reselection to the E-UTRA without
further notice (see Section 1.10.7.1). While this will rather lead to paging failures in the 3G part
of the network, continuous toggling of radio access will also lead to performance degradation and
accessibility failures that impact both radio access technologies.

这种情况怎么规避？

UTRA CELL_PCH and URA_PCH are allowed to perform cell reselection to the E-UTRA without
further notice。

这样，Lte不知道用户在，paging会在utran发起，寻呼失败。

前段时间有帖子提到的一次打电话不通，第二次通的现象，是否可以推断是这样的原因造成的呢？如果是，这是协议的缺陷，现网怎么规避；协议的演进是否有解决这种情况？