Secondary Cell Carrier Access via Operational Mode Signaling
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Solution Overview
Problem
Current LTE-Advanced systems face challenges in achieving accurate time and frequency synchronization for Secondary Cell Carrier (SCC) access due to the inefficiency of existing Physical Discovery Channels, which are unsuitable for quick and precise synchronization in unlicensed bands shared with other systems.
Innovation Solution
The implementation of a method where a Primary Cell Carrier (PCC) monitors and transmits data indicative of operational modes to a user terminal, allowing it to selectively request SCC access based on comparisons with broadcast channel data, thereby optimizing time and frequency synchronization through controlled operational mode selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Physical Discovery Channel (PDCH) is used for SCC discovery, then the SCC can be discovered, but accurate time and frequency synchronization cannot be achieved quickly
Solution Approach 1:
The patent segments the discovery process into two distinct phases: initial SCC discovery using PDCH, and subsequent precise time/frequency synchronization using PCC reference signals. This segmentation allows each channel to perform its optimized function - PDCH for discovery and PCC for precise synchronization - thereby resolving the contradiction between discovery capability and synchronization accuracy/speed.
Solution Approach 2:
The patent introduces the PCC as an intermediary element that mediates between the PDCH discovery process and the SCC synchronization requirement. The user terminal uses PCC reference signals as an intermediate reference to achieve accurate time and frequency synchronization for the SCC, rather than relying solely on the PDCH which lacks the necessary precision.
2Ease of operation
If the user terminal continuously monitors the broadcast channel for SCC access, then SCC access can be requested, but resource scanning overhead increases
Solution Approach 1:
The patent applies preliminary action by having the network pre-configure multiple operational modes for the SCC before the user terminal needs to access it. The user terminal receives and stores this operational mode information in advance, so when SCC access is needed, it can quickly compare its current state with the pre-received operational modes without continuous monitoring, thereby reducing scanning overhead while maintaining access capability.
Solution Approach 2:
Instead of continuously monitoring the broadcast channel (excessive action), the patent uses partial monitoring where the user terminal only needs to periodically check for operational mode updates and compare with pre-configured modes. This partial action approach maintains SCC access capability while significantly reducing the energy consumption and resource overhead associated with continuous monitoring.
Data Source
AI summary
Embodiments of the invention provide methods, devices and computer programs arranged to control access to a Secondary Cell Carrier (SCC) by a user terminal. The user terminal having a first functional state in which the user terminal is arranged to monitor for a broadcast channel associated with the SCC, and a second functional state, different to said first functional state. One embodiment comprises an apparatus comprising a processing system arranged to cause the apparatus to: receive data indicative of a plurality of operational modes assigned to the SCC; and transmit a signalling message comprising data indicative of said plurality of operational modes for receipt by the user terminal, whereby to configure the user terminal into the first functional state, wherein the user terminal is arranged to selectively request access to resources of the SCC on the basis of a comparison between data contained in said signalling message and data contained in a transmission received on the broadcast channel.