SIP Header Compression Using 3G Dictionaries and Encoding Assistant
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Solution Overview
Problem
Current SIP message sizes are large, leading to significant initiation latency in multimedia communication services like VoIP and Video Telephony, which can be improved by reducing the SIP header size to fit within shorter bandwidth control channels and reduce call setup times.
Innovation Solution
A new protocol that compresses SIP header fields by encoding static information using a Static Dictionary for Signaling Compression (SIGCOMP) and a 3G dictionary, transmitting only dynamic information, implemented by the Mobile Station, User Agent, and Proxy SIP Server, with an Encoding Assistant function for encoding and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If standard SIP protocol is used for multimedia communication, then communication functionality is complete, but message size is large causing significant initiation latency
Solution Approach 1:
The SIP message is segmented into static header fields and dynamic header fields. Static fields are compressed using a dictionary-based approach where common values are replaced with shorter codes, while dynamic fields are transmitted in full. This segmentation allows selective optimization of message size without losing essential information.
Solution Approach 2:
The message format parameters are changed by introducing a compressed header structure with dictionary-based encoding. The protocol transitions from transmitting full text values to transmitting coded references, fundamentally changing how header information is represented and transmitted.
2Productivity
If SIP header size is reduced to fit within shorter bandwidth control channels, then transmission efficiency improves, but protocol complexity increases due to compression requirements
Solution Approach 1:
A dictionary is pre-established and shared between sender and receiver before actual message transmission. This preliminary action allows both parties to have the same encoding/decoding reference, simplifying the compression process during actual communication without requiring complex real-time negotiation.
Solution Approach 2:
Instead of transmitting full header values, the system transmits copied references (codes) from the pre-established dictionary. This copying approach dramatically reduces message size while the complexity is confined to maintaining and accessing the dictionary structure.
3Quantity of substance
If compression encoding is applied to SIP headers, then message size decreases, but processing overhead increases at encoding and decoding
Solution Approach 1:
Compression is applied selectively only to static header fields that benefit from dictionary encoding, while dynamic fields are transmitted without compression. This partial application of compression avoids the overhead of encoding/decoding entire messages, focusing computational effort only where it provides the most benefit.
Data Source
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AI summary
A SIP header reduction protocol operating on a communication network to compress the SIP header fields on SIP control messages used to initiate a SIP communication session. The new protocol is implemented on the mobile use equipment (UE) (301) and P-CSCF proxy SIP server (302). The prior SIGCOMP compression dictionary is used to compress those header field parameters defined by the SIGCOMP dictionary. A new 3G Dictionary is implemented with header field parameters for several wireless specific data elements and parameters necessary to access various wireless technologies and services which are missing from the SIP/SDP based SIGCOMP dictionary. Finally, an Encoding Assistant (EA) (310, 355) function is implemented on the UE and P-CSCF that operates a standard encoding and decoding of SIP message header fields to reduce those SIP header fields that are dynamic over time but are essentially static in terms of most user communication. The EA parameters can be updated periodically, while the 3G and SIGCOMP dictionary are static and not updated.