有高手研究過(guò) CDMA(IS-95) 里面信令解析的內(nèi)容嗎？

我現(xiàn)在遇到點(diǎn)問(wèn)題，在我解析設(shè)備給我返回的層3信息時(shí)，會(huì)遇到這么一種情況，CRC效驗(yàn)通過(guò)了，但是發(fā)現(xiàn)有的幀中，信令的類型不在已知的范圍里。

比如 Access Channel 信道（其他信道也出現(xiàn)過(guò)），信令名稱對(duì)應(yīng)的二進(jìn)制代碼如下：

Registration Message = 00000001
Order Message = 00000010
Data Burst Message = 00000011
Origination Message = 00000100
Page Response Message = 00000101
Authentication Challenge Response Message = 00000110
Status Response Message = 00000111
TMSI Assignment Completion Message = 00001000
PACA Cancel Message = 00001001
Extended Status Response Message = 00001010

但是我解析的過(guò)程中，發(fā)現(xiàn)信令的代碼是 01000010 ， 前面的第2位變成1了。

然后我在文檔中發(fā)現(xiàn)這么一段話，如下：

If a mobile station receives any message with a MSG_TYPE specified in Table 7.7.2.3-1
other than a Channel Assignment Message or an Extended Channel Assignment Message
addressed to the mobile station, it shall process the ACK_SEQ and VALID_ACK fields of
layer 2 as specified in 6.6.3.1.2. If, after processing the ACK_SEQ and VALID_ACK fields,
an access attempt is still in progress, the mobile station shall ignore the ACK_REQ field of
layer 2 and the layer 3 fields of the message; otherwise, the mobile station shall process the
ACK_REQ field as described in 6.6.3.1.2 and the layer 3 fields of the message as described
below.

這段話的意思，好像是說(shuō)，如果信令的代碼超出已知的范圍了，達(dá)到某種條件，就不要了。
哪位大哥知道怎么理解呀？超出信令范圍的幀，我怎么辦呀？