Cell Acquisition in Millimeter Wave Systems
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Solution Overview
Problem
In LTE networks, the inefficient method of acquiring high frequency carriers in millimeter wave systems due to high path loss, heavy shadowing, and rain attenuation hinders reliable transmission, particularly in asymmetric heterogeneous deployments where 4G BSs control aspects of 5G BSs and MSs communicate using low and high frequency carriers.
Innovation Solution
A method and system where a 4G base station determines the location of a Mobile Station (MS) and identifies nearby 5G base stations, transmitting a second frequency carrier cell search command with specific synchronization slots and parameters, allowing the MS to efficiently search and identify the 5G base station by reducing the number of synchronization slots and preambles to monitor based on location information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the MS searches for high frequency carrier cells using traditional methods, then the cell acquisition is performed, but the power consumption and processing effort are excessively high due to monitoring all synchronization slots
Solution Approach 1:
The low frequency base station performs preliminary actions by determining the MS location and identifying candidate high frequency base stations before the actual cell search. It prepares and transmits search command information containing synchronization slot indicators in advance, so the MS only needs to monitor specific slots rather than all slots, significantly reducing power consumption while ensuring reliable acquisition
Solution Approach 2:
The synchronization slots are segmented into candidate slots and non-candidate slots based on location information. The search command information divides the monitoring task into specific time slots indicated by synchronization slot indicators, allowing the MS to focus only on relevant segments rather than processing the entire synchronization space
2Reliability
If the MS monitors all synchronization slots to ensure complete cell search coverage, then all potential cells are detected, but the processing effort and time required are excessively high
Solution Approach 1:
The system performs preliminary analysis at the low frequency base station to determine which high frequency base stations are candidates based on MS location. The search command information with synchronization slot indicators is prepared in advance, enabling the MS to skip unnecessary slots and acquire cells faster without compromising completeness
Solution Approach 2:
Different synchronization slot monitoring requirements are applied based on local conditions (MS location and identified candidate base stations). The search command information provides location-specific synchronization slot indicators, making the monitoring process adaptive to local rather than applying uniform monitoring to all slots
3Use of energy by moving object
If the system uses location-based filtering to reduce synchronization slots to monitor, then power consumption is reduced, but the complexity of determining location and identifying candidate base stations increases
Solution Approach 1:
The low frequency base station acts as an intermediary that handles the complex tasks of location determination and candidate base station identification. It processes the MS location information and generates search command information with synchronization slot indicators, offloading the complexity from the MS while still achieving power savings through selective monitoring
4Reliability
If traditional cell search methods are used in asymmetric heterogeneous deployments, then cell acquisition is achieved, but the efficiency is low due to not utilizing location information and synchronization slot patterns
Solution Approach 1:
The system uses feedback from MS location information to dynamically determine which high frequency base stations are candidates and which synchronization slots to monitor. The search command information incorporates this feedback by providing synchronization slot indicators based on the MS's specific location and the identified candidate base stations, making the acquisition process efficient and adaptive
Data Source
AI summary
A method of enabling cell acquisition in a wireless communication includes determining, by a first base station, a Mobile Station (MS) located at a granularity of a first frequency carrier cell sector level, identifying at least one second base station within the first frequency carrier cell sector level, transmitting a second frequency carrier cell search command to the MS and identifying, by the MS, the second frequency carrier cell based on one or more parameters defined in the search command. The first frequency carrier cell enables the MS to search for the second frequency carrier cell by providing a predefined number of synchronization slots to be monitored based on the location information of the MS.