Reserved Code Handoff Access via Random Sub-Channel
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Solution Overview
Problem
In cellular wireless communication systems, handoff access procedures face challenges such as collision resolution and efficient channel resource utilization due to the difficulty in obtaining precise time differences and uncertain transmission times, leading to potential call drops and reduced channel resource utilization.
Innovation Solution
A handoff access method based on random access channels, where a source BS requests a handoff to a target BS, allocating a reserved character code and random access sub-channel to the mobile terminal, allowing it to initiate a handoff access procedure without collisions by using a reserved character code and sub-channel selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target BS reserves shared wireless channel resources in advance for handoff, then the handoff success rate is improved, but the system complexity increases and the channel resource utilization efficiency decreases
Solution Approach 1:
The target base station performs preliminary actions by pre-configuring and reserving random access sub-channels and character codes specifically for handoff terminals before actual handoff occurs. This preliminary preparation enables fast handoff execution without real-time resource allocation complexity, resolving the contradiction between handoff reliability and system complexity
Solution Approach 2:
The random access resources are segmented into dedicated handoff resources (specific sub-channels and character codes) separate from common random access resources. This segmentation isolates handoff procedures from general access procedures, improving handoff success rate while maintaining manageable system complexity through specialized resource pools
2Loss of time
If the target BS reserves shared wireless channel resources in advance for handoff, then the handoff delay is reduced, but the channel resource utilization efficiency decreases
Solution Approach 1:
Random access sub-channels and character codes are pre-configured and reserved for handoff purposes before actual handoff events occur. This preliminary setup eliminates real-time resource allocation delays, enabling immediate handoff execution while maintaining efficient resource utilization through dedicated resource pools that are only activated when needed
Solution Approach 2:
The system introduces a dedicated dimension for handoff resources separate from common random access resources. By creating specialized random access sub-channels and character codes specifically for handoff, the system achieves fast handoff execution without compromising overall channel resource utilization efficiency, as handoff and common access operate in separate resource dimensions
3Productivity
If multiple terminals perform random access simultaneously on the same channel, then the channel resource utilization is improved, but collision probability increases leading to access failure
Solution Approach 1:
Random access resources are segmented into multiple random access sub-channels, each with multiple character codes. This segmentation allows multiple terminals to access simultaneously across different sub-channels and code combinations, maintaining high channel utilization while reducing collision probability through resource diversification
Solution Approach 2:
The system expands the random access resource space by introducing multiple dimensions: multiple random access sub-channels (time-frequency resources) and multiple character codes (sequence resources). This multi-dimensional resource space allows terminals to select from numerous combinations, enabling high concurrent access rates while maintaining low collision probability through increased resource diversity
Data Source
AI summary
A handoff access method and device based on a random access channel is provided, the method comprising: a source BS sends a handoff request message to a target BS; the target BS sends a handoff response message to the source BS, and then the source BS forwards a handoff command with the content of the handoff response message to the mobile terminal, wherein a sequence number of a reserved character code allocated by the target BS to the mobile terminal and a random access sub-channel that the reserved character code is located in are contained in the handoff command message; after receiving the handoff command message, the mobile terminal selects the reserved character code and the random access sub-channel that the reserved character code is located in; and a handoff access procedure is initialized on the random access sub-channel by the target BS and the mobile terminal.