Adaptive Pilot Pattern Control for Mobile Communication Reliability
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Solution Overview
Problem
In mobile communication systems, existing methods for transmitting control information using pilot patterns in CDMA systems face challenges such as increased error rates and mis-operations due to insufficient pilot duration, leading to suboptimal power control performance.
Innovation Solution
The method involves selecting a pilot pattern based on control information and inserting it into a pilot field, allowing for adaptive power offset allocation to minimize error rates and improve power control by using different transmission powers for various types of control information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed pilot pattern is used for transmitting control information, then the system structure is simple, but the error rate increases and power control performance deteriorates
Solution Approach 1:
The patent applies dynamics by making the pilot pattern selectable and adaptable based on control information type rather than fixed. The system dynamically chooses between different pilot patterns (first pattern for ACK/NACK, second pattern for other control information) to optimize detection accuracy for each specific control information type, thereby improving reliability without requiring complex adaptive mechanisms for all scenarios.
Solution Approach 2:
The patent implements local quality by assigning different pilot patterns to different types of control information based on their specific detection requirements. ACK/NACK information receives a dedicated first pilot pattern optimized for its characteristics, while other control information uses a second pilot pattern, allowing each control information type to benefit from locally optimized detection parameters.
2Measurement precision
If uniform transmission power is used for all control information, then power control is simple, but detection accuracy deteriorates for different control information types
Solution Approach 1:
The patent applies local quality by allocating different power offsets to different control information types. The base station assigns a first power offset for ACK/NACK information and a second power offset for other control information, allowing each type to receive transmission power optimized for its specific detection requirements and channel conditions.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting transmission power parameters (power offsets) based on control information type and channel conditions. The system changes the power allocation parameter from a uniform value to differentiated values, improving detection accuracy for each control information type without requiring complete reconfiguration of the power control system.
3Reliability
If pilot duration is extended to improve detection accuracy, then error rate decreases, but transmission efficiency deteriorates
Solution Approach 1:
The patent applies partial action by using different pilot patterns with appropriately sized pilot durations for different control information types. Instead of uniformly extending pilot duration for all control information, the system uses a first pilot pattern with optimized duration for ACK/NACK and a second pattern for other control information, achieving sufficient detection reliability without excessive pilot overhead that would reduce transmission efficiency.
Data Source
AI summary
An apparatus and method for transmitting a control signal using a symbol or bit pattern of an existing pilot channel, instead of using the time multiplexing method in the separate code channel or the existing physical channel, and reducing an error rate while a reception side detects the control signal are provided. For that purpose, a transmission side allocates transmission power corresponding to a pilot pattern determined according to the control information. A corresponding reception side detects control information based on a pilot pattern of pilot bits inserted in a dedicated physical channel (DPCH) and generates transmit power control (TPC) bits referring to a target reception power which is set based on the control information.