Extended SFN for Machine-Type Communication DRX
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Solution Overview
Problem
Current mobile communication systems, particularly in LTE, face limitations in extending the Discontinuous Reception (DRX) cycle for machine-type communication devices, which restricts power savings due to the fixed length of the System Frame Number (SFN), affecting the coexistence with traditional UEs.
Innovation Solution
The method involves defining a second SFN where one cycle corresponds to one bit, transmitting additional SFN bits to User Equipment (UE), and determining a first SFN for paging signal transmission, allowing for a longer DRX cycle without interfering with existing UEs, by using extended SFN bits in Master Information Blocks (MIB) or System Information Blocks (SIB), or introducing a new SIB for machine-type communication devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the DRX cycle is extended for machine-type communication devices, then power consumption is reduced, but the fixed length of the System Frame Number (SFN) limits the maximum DRX cycle extension
Solution Approach 1:
The patent extends the SFN from 10 bits to 20 bits, effectively adding another dimension of time representation. This allows the DRX cycle to be extended from a maximum of 10.24 seconds (with 10-bit SFN) to over 35 hours (with 20-bit SFN), enabling machine-type communication devices to remain in sleep mode much longer and significantly reducing power consumption.
Solution Approach 2:
The patent segments the SFN into two parts: a first SFN (10 bits) for legacy LTE operations and a second SFN (10 bits) for extended DRX functionality. This segmentation allows the system to maintain compatibility with existing UEs while providing extended DRX capabilities for machine-type communication devices. The first SFN continues to operate with its original 10.24-second cycle, while the second SFN enables much longer DRX cycles when needed.
2Use of energy by moving object
If additional SFN bits are introduced to extend the DRX cycle, then machine-type communication devices can save more power, but compatibility with traditional UEs may be affected
Solution Approach 1:
The patent applies local quality by making the extended SFN functionality optional and device-specific. Machine-type communication devices can utilize the full 20-bit SFN for extended DRX operations, while traditional UEs continue to use only the first 10 bits. This localized application of the extended SFN ensures that power-saving benefits are achieved for machine-type devices without disrupting the operation of traditional UEs.
Solution Approach 2:
The extended SFN structure serves multiple functions: it maintains backward compatibility with legacy LTE systems through the first 10 bits, provides extended DRX capability for machine-type communication devices through the additional 10 bits, and enables both short and long DRX cycles within the same system. This multi-functionality allows the network to support diverse device requirements simultaneously.
Data Source
AI summary
A method and an apparatus for supporting a discontinuous reception (DRX) operation in a Node B in a mobile communication system are provided. The method includes defining a second System Frame Number (SFN) where one cycle of a first SFN corresponds to one bit, transmitting information on the second SFN to a User Equipment (UE), determining a second SFN which is used to transmit a paging signal to the UE, determining a first SFN which is used to transmit the paging signal in the determined second SFN, and transmitting the paging signal to the UE at the determined first SFN.