Mobile Satellite Paging via NRSPCA Traffic Class Detection
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Solution Overview
Problem
In mobile satellite communication systems, the compression and encryption of SIP messages prevent GPRS gateways from identifying the type of incoming call, leading to inefficient paging and QoS management, as they cannot distinguish between different service types like voice and data, resulting in suboptimal resource allocation and increased power consumption.
Innovation Solution
A system that determines the type of incoming signal and modifies the paging signal amplitude and waveform to effectively page user terminals, utilizing the Network Requested Secondary PDP Context Activation (NRSPCA) procedure to convey traffic class information, enabling enhanced paging and optimal QoS for specific service types without decrypting the SIP message.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If enhanced paging is used to notify users of incoming calls, then user accessibility is improved, but satellite power consumption increases
Solution Approach 1:
The patent applies local quality by differentiating paging strategies based on service type. Enhanced paging with higher power is selectively applied only to voice calls (conversational traffic class) rather than all incoming calls uniformly. This allows the system to maintain high user accessibility for critical voice services while reducing overall power consumption by using standard paging for less critical services.
Solution Approach 2:
The patent changes the paging parameter (power level) based on traffic class identification. By determining the service type from SIP message headers before paging, the system adjusts the paging power parameter dynamically - using enhanced power for voice calls and standard power for other services. This parameter change resolves the contradiction by optimizing the balance between accessibility and power consumption.
2Reliability
If SIP messages are compressed and encrypted for security and efficiency, then network security and bandwidth utilization are improved, but gateway ability to identify service type deteriorates
Solution Approach 1:
The patent extracts the traffic class identification capability from the full SIP message content. Instead of requiring decryption or analysis of the complete encrypted SIP message body, the system extracts service type information from specific header fields (such as SDP offer/answer headers) that remain visible even when the message is compressed and encrypted. This allows security to be maintained while enabling service type detection.
Solution Approach 2:
The patent introduces an intermediary approach where the gateway analyzes visible header information as a proxy for service type identification. Rather than directly parsing the encrypted message content, the gateway uses intermediary header fields (like SDP headers) that provide sufficient information to determine traffic class without compromising the security of the encrypted message body.
3Reliability
If enhanced paging is applied to all incoming calls, then user notification reliability is improved, but resource allocation efficiency deteriorates
Solution Approach 1:
The patent applies local quality by tailoring paging resources to the specific needs of different service types. Enhanced paging with higher reliability is applied locally to voice calls where it is most critical, while standard paging is used for data and other services. This selective application optimizes resource allocation efficiency while maintaining notification reliability for services that require it.
Solution Approach 2:
The patent applies partial action by providing enhanced paging only to the extent necessary for specific service types (voice calls) rather than uniformly to all incoming calls. This partial application of enhanced paging ensures adequate notification reliability for critical services while avoiding excessive resource consumption for services that do not require such high reliability.
Data Source
AI summary
A system and method is provided to enable enhanced paging for 3GPP IMS based Mobile Satellite Communication is presented. The method is achieved by utilizing the network requested secondary PDP context activation (NRSPCA) features of 3GPP release 7. NRSPCA involves interaction between P-CSCF, GGSN, and SGSN that eventually allows SGSN to identify the traffic type of the incoming call without looking at the compressed SIP messages. RAN can do enhanced paging, if necessary; based on the request secondary PDP context activation message, if the Paging Cause is indicating conversational class. In another embodiment, enhanced paging can be achieved by marking the packet with an appropriate DSCP code, which is done by the P-CSCF. SGSN can populate the paging cause with enhanced paging code based on the DSCP code provided or RAN can escalate paging to enhanced paging by examining the DSCP code.