A method for preventing state variable from abnormal update

Abstract

This invention discloses a method for preventing state variables from abnormal refreshment used in the communication system including a sending entity and a receiving entity, among which, communication between the sending entity and the receiving entity applies automatic re-transmission structure. The method also includes: when the receiving entity receives a PDU, it computes the distance between the received PDU sequence number and the sequence number corresponding to the state variable VR(H) to decide if the computed distance is larger than the set refreshed amplitude, if so, it discards the PDU, otherwise, it refreshes VR(H) to the sequence number of the current received PDU+1 which can avoid abnormal process to the sliding window protocol.

Description

technical field [0001] The invention relates to a data unit processing technology, in particular to a method for preventing abnormal updating of state variables under an automatic retransmission mechanism in a communication system. Background technique [0002] The Universal Mobile Telecommunications System (UMTS, Universal Mobile Telecommunications System) is a third-generation mobile communication system that adopts Wideband Code Division Multiple Access (WCDMA) air interface technology, and it is usually called a WCDMA system. The UMTS system adopts a structure similar to that of the second-generation mobile communication system, including a radio access network (RAN, Radio Access Network) and a core network (CN, CoreNetwork), where the radio access network is used to handle all wireless-related Function, the core network is responsible for handling all voice calls and data connections in the UMTS system, and realizes the switching and routing functions with external netw...

AI Technical Summary

Problems solved by technology

As shown in Figure 4, at a certain moment, the sending window and the receiving window move to the state shown in the figure. If the receiving entity receives a PDU with a sequence number of 100 at this time, according to the current protocol, since the PDU with a sequence number of 100 Between VR(H) and VR(MR), VR(H) will be updated to 101, which will trigger the exception handling of the protocol, which will cause the reset to occur

[0013] In addition, in order to prevent the problem of abnormal handling of the protocol, it is usually necessary to set the value of n to be large, but the larger the value of n, it will cause each PDU to carry a sequence number with a long number of digits in transmission, thereby increasing the number of each PDU. header overhead, which means that more air interface resources will be occupied to transmit the same data payload, which is more costly

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