Method of eliminating business flow jitter and slip code in CDMA communication system
A communication system and code division multiple access technology, applied in the field of wireless mobile communication, can solve problems such as dropped calls, affect voice quality, increase the complexity of frame selection processing, etc., and achieve the effect of improving QoS and eliminating delay jitter
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Embodiment 1
[0022] Embodiment 1 Delay jitter elimination, see figure 2 , the dotted arrow in the figure indicates the ideal arrival time of the service frame.
[0023] A. At this time, the sequence number that Sdu expects is 3. Although the service frame with Fsn=3 does not arrive on time due to delay jitter, it arrives and is cached before the receiving time, so Sdu can still get the desired frame, and the sequence number that Sdu expects It is also increased by 1 according to the normal situation.
[0024] B. At this time, the sequence number expected by Sdu is 4. Although the delay jitter increases further, the service frame still arrives before the receiving time, which does not exceed the dejitter capability of Sdu. Therefore, although the arrival of business frames is jittered at random, the output of Sdu still maintains the validity, and the time interval is uniform 20ms.
[0025] from figure 2 It can be seen from the figure that the anti-jitter capability of Sdu is the maximu...
Embodiment 2
[0026] The processing of embodiment 2 sliding code, situation 1-physical layer 20ms clock is faster than local, refer to image 3 (In the figure, the clock deviation between the physical layer 20ms and the local 20ms clock is large, Figure 4 as well).
[0027] A. At this time, the sequence number expected by Sdu is 2, and the desired frame can be fetched, and the sequence number is increased by 1 according to the normal situation. At the same time, the frame of Fsn=3 has been cached in the buffer, and the slip code has appeared.
[0028] B. At this time, the expected sequence number of Sdu is 3, and the desired frame can still be fetched, but the cache time is longer than 20ms. Frames with Fsn=4 are also buffered. Since the received service frame Fsn is greater than the expected frame number of Sdu for n=2 consecutive times, the expected frame number of Sdu is adjusted forward to 5.
[0029] C. At this time, the frame number expected by Sdu is 5, the frame with Fsn=4 in t...
Embodiment 3
[0030] The processing of embodiment 3 sliding code, situation 2-physical layer 20ms clock is slower than local, refer to Figure 4 .
[0031] A. At this time, the sequence number expected by Sdu is 3, but the service frame with Fsn=3 has not arrived yet, and the buffer is empty, so Sdu cannot get the desired frame. To maintain continuity of output, Sdu submits an empty frame. The serial number is incremented by 1 as usual. When the frame with Fsn=3 arrives, because Fsn is smaller than the sequence number 4 expected by Sdu at that time, it is discarded directly.
[0032] B. At this time, the serial number expected by Sdu is 4, and the buffer is empty. Sdu still cannot get the desired frame, and continues to submit an empty frame. If the serial number is not adjusted, Sdu will never be able to get the desired frame. Since the received service frame Fsn is smaller than the expected frame number of Sdu for n=2 consecutive times, the expected frame number of Sdu is adjusted bac...
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