Clock Synchronization in Cellular Networks via Grant-Free Transmission
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Solution Overview
Problem
Current cellular mobile networks fail to meet the requirements of symmetrical delay and low jitter necessary for effective clock synchronization protocols, leading to unwanted coupling between radio procedures and application layers.
Innovation Solution
The method involves disabling Carrier-Aggregation, Coordinated MultiPoint, and Dual Connectivity for IP communication flows, setting target radio Block Error Rate to match packet loss rates, calculating radio packet size for single transmissions, bypassing radio scheduler queues, and utilizing grant-free transmission to ensure symmetrical delay and low jitter in uplink and downlink channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Carrier-Aggregation, Coordinated MultiPoint, and Dual Connectivity are used to improve spectral efficiency and cell coverage, then spectral efficiency and coverage are improved, but symmetrical delay and jitter performance deteriorate
Solution Approach 1:
The patent segments IP communication flows into two categories: clock synchronization flows and regular data flows. By applying different transmission modes to different flow types, the system can maintain spectral efficiency for regular data while ensuring symmetrical delay for synchronization packets. This is achieved by disabling CA, CoMP, and DC specifically for clock synchronization flows while maintaining them for other traffic.
Solution Approach 2:
The patent applies local quality by implementing grant-free transmission specifically for uplink clock synchronization packets from UE to base station, while maintaining conventional scheduled transmission for other traffic. This localized application of grant-free transmission ensures low jitter for synchronization packets without affecting overall spectral efficiency of the network.
2Loss of time
If grant-free transmission is used to reduce uplink delay, then uplink delay is reduced, but radio resource control complexity increases
Solution Approach 1:
The patent extracts the scheduling decision-making function from the base station for clock synchronization traffic and transfers it to the UE. The UE autonomously transmits synchronization packets without waiting for base station grants, eliminating scheduling delays. The base station simply monitors and processes these packets without complex scheduling operations, thus reducing both delay and control complexity.
Solution Approach 2:
The patent configures grant-free transmission parameters in advance for clock synchronization flows before actual transmission occurs. This preliminary configuration includes setting transmission power, resource allocation, and other parameters beforehand, allowing the UE to immediately transmit synchronization packets without real-time scheduling delays while maintaining simple base station processing.
Data Source
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AI summary
A method for clock synchronization of protocols in a network comprising a base station, BS, the BS comprising a BS scheduler, a user equipment, UE, and a master clock as an Over-the-Top, OTT, IP service on uplink and downlink channels, the method comprising the steps of: a) enabling, by the network, one or more IP communication flows between interfaces of the master clock and the UE for IP time synchronization packets or packets with similar symmetrical delay and low jitter requirements; b) receiving at the UE and the BS packets of these IP communication flows; c) disabling, at the BS and the UE, the use of Carrier-Aggregation, CA, Coordinated MultiPoint, CoMP, and Dual Connectivity, DC, for data of these IP communication flows; d) setting, at the BS and the UE, the target radio Block Error Rate, BLER, of the uplink and downlink channels to a value equal to or less than that of the IP communication flow's target packet loss rate; e) calculating, at the BS and the UE, the radio packet size so as to ensure that each packet is transmitted over a single radio transmission; f) signaling, from the network to the BS scheduler, a signal indicating to bypass radio scheduler queues; g) receiving a signal at the BS scheduler to bypass radio scheduler queues; h) signaling, from the BS to the UE, a signal indicating to utilize grant-free transmission on the uplink channel; and i) receiving, at the UE, a signal indicating to utilize grant-free transmission on the uplink channel.