Network-Assisted Cell Selection for 2-Step Random Access
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Solution Overview
Problem
In wireless communications systems with dense deployments of cells, user equipment (UE) faces challenges in accessing cells that are in energy saving states, leading to increased power consumption and inefficiencies in cell selection procedures.
Innovation Solution
The technology facilitates network-assisted cell selection by allowing a UE to transmit a PRACH preamble and MsgA on a first cell, receive a random access response (MsgB), identify a serving cell, and transmit a connection complete message, even if the serving cell is in an energy saving state. This is achieved by coordinating access between the UE and neighbor cells through a designated cell that monitors system information and paging messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cells are deployed in energy saving states to reduce network energy consumption, then energy efficiency is improved, but UE access capability deteriorates
Solution Approach 1:
The patent introduces a coordinator cell as an intermediary that enables UEs to access target cells in energy saving states. The coordinator cell receives random access preambles from UEs and transmits random access responses on behalf of target cells, allowing UEs to communicate with cells without directly establishing connections to those cells. This mediator approach resolves the contradiction by maintaining network energy savings while preserving UE access capability through indirect communication.
Solution Approach 2:
The patent implements preliminary actions by having the coordinator cell continuously monitor system information and maintain signaling connections with target cells before actual UE access is needed. The network pre-configures the coordinator cell with information about target cells in energy saving states, enabling UEs to access these cells without requiring the target cells to be in active states. This advance preparation allows the system to balance energy consumption with access capability.
2Productivity
If multiple cells are densely deployed to boost capacity and reduce signal blockage, then network capacity is improved, but UE power consumption increases
Solution Approach 1:
In dense cell deployments, the coordinator cell serves as a mediator that reduces the number of cells UEs need to directly monitor and measure. Instead of actively scanning multiple neighbor cells in energy saving states, UEs only need to interact with the coordinator cell, which aggregates information from multiple target cells. This significantly reduces UE power consumption while the network maintains the benefits of dense deployment through the coordinator's comprehensive cell management.
Solution Approach 2:
The patent merges the functions of multiple cells into the coordinator cell by having it aggregate system information, paging messages, and random access signaling from multiple target cells. The coordinator cell combines the operational status and communication functions of multiple energy saving cells into a single active interface for UEs, reducing UE processing requirements and power consumption while preserving access to multiple cells for network capacity.
3Loss of energy
If cells transition to energy saving states to reduce operational cost, then energy efficiency is improved, but cell selection procedure complexity increases
Solution Approach 1:
The coordinator cell acts as an intermediary that simplifies cell selection procedures by centralizing the complexity of managing energy saving state transitions. Instead of UEs directly handling complex interactions with multiple cells in energy saving states, the coordinator cell manages these complexities through standardized signaling protocols, presenting a simplified interface to UEs while maintaining the energy efficiency benefits.
Solution Approach 2:
The network performs preliminary actions by pre-configuring coordinator cells with information about target cells in energy saving states, including their identification parameters and access conditions. This advance preparation eliminates the need for UEs to perform complex real-time analysis of multiple cell states, reducing procedure complexity while maintaining energy efficiency through pre-established access pathways.
Data Source
AI summary
Various aspects of the present disclosure relate to network-assisted cell selection. In some embodiments, a network employs a cell within a location to coordinate access between the UE and other cells (e.g., neighbor cells) that are candidates to be a serving cell for the UE within the location but may be in an energy saving state of operation when a UE initiates an access procedure.