Handoff Access via Random Access Sub-Channel Mapping
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Solution Overview
Problem
In cellular wireless communication systems, handoff access is challenging due to collisions during random access, especially when no reserved character codes are allocated, leading to potential handoff failures and inefficient channel resource utilization.
Innovation Solution
A handoff access method and device that involves sending a handoff request message from a source BS to a target BS, followed by a handoff response message without reserved character codes, allowing the mobile terminal to select a random access sub-channel without reserved codes, and initiating a handoff access procedure on that sub-channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reserved character codes are allocated for handoff access, then handoff reliability is improved, but channel resource utilization deteriorates due to redundant reservations
Solution Approach 1:
The target base station performs preliminary preparation by creating a mapping relationship between reserved character codes and random access sub-channels before handoff occurs. This allows the mobile terminal to directly use the mapping information during handoff without requiring real-time resource allocation, ensuring reliable handoff while avoiding redundant resource reservations.
Solution Approach 2:
The mobile terminal autonomously selects an appropriate random access sub-channel based on the mapping relationship provided in the handoff command, without requiring the source base station to reserve specific resources. This self-service approach eliminates the need for redundant resource reservations by the source base station while ensuring successful handoff access.
2Reliability
If the source BS reserves wireless channel resources for handoff, then handoff reliability is improved, but system complexity increases and resource utilization decreases
Solution Approach 1:
The resource reservation function is extracted from the source base station and transferred to the target base station. The target base station prepares the mapping relationship between character codes and sub-channels, while the source base station only needs to forward the handoff command with this mapping information. This extraction eliminates the complexity of resource reservation management at the source base station while maintaining handoff reliability.
3Reliability
If the target BS reserves wireless channel resources early, then handoff reliability is improved, but channel resource utilization deteriorates due to early reservation
Solution Approach 1:
The target base station performs preliminary preparation by establishing the mapping relationship between reserved character codes and random access sub-channels before handoff. However, the actual wireless channel resources are not reserved in advance but are allocated dynamically when the mobile terminal autonomously selects a sub-channel based on the mapping information, thus ensuring handoff reliability while avoiding resource waste from early reservation.
4Loss of energy
If no reserved character codes are allocated, then channel resource utilization is improved, but handoff access reliability deteriorates due to collisions
Solution Approach 1:
The random access resources are segmented into multiple random access sub-channels, each associated with specific reserved character codes through the mapping relationship. The mobile terminal autonomously selects an appropriate sub-channel based on the mapping information, which divides the collision-prone random access process into multiple independent sub-channels, thereby maintaining high resource utilization while improving handoff reliability.
Solution Approach 2:
The mapping relationship between reserved character codes and random access sub-channels acts as an intermediary mechanism. It guides the mobile terminal to select appropriate sub-channels without requiring actual resource reservation, thus preventing collisions while maintaining efficient resource utilization. The mapping information serves as a mediator between the reserved character codes and the physical random access resources.
Data Source
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AI summary
A handoff access method and device based on a random access channel is provided, the method includes the following steps: step a, a source BS sends a handoff request message to a target BS, requesting switching the mobile terminal it serves to the target BS; step b, the target BS sends a handoff response message to the source BS, and then the source BS forwards a handoff command with its content to the mobile terminal, wherein the handoff command message does not include reserved character codes; step c, after receiving the handoff command message, the mobile terminal determines that the handoff command message does not include the reserved character codes, and then selects a random access sub-channel; and step d, the target BS and the mobile terminal initiate a random access procedure on the random access sub-channel.