Radio Communication Device Inter-Code Interference Suppression
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Solution Overview
Problem
In 3GPP LTE PUCCH, the cyclic shift interval between CCEs for CQI and ACK/NACK signals is insufficient, leading to increased inter-code interference between code-multiplexed signals.
Innovation Solution
A radio communication apparatus with a configuration that includes a first spreading section using sequences with mutually different cyclic shift values and a second spreading section, controlled to maintain a minimum cyclic shift difference greater than or equal to the difference between second response signals from multiple mobile stations, thereby suppressing inter-code interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If code-multiplexing is performed using ZC sequences with small cyclic shift intervals to increase the number of multiplexed signals, then the capacity for code-multiplexed signals increases, but inter-code interference between signals increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the cyclic shift interval parameter based on channel conditions. When channel conditions are good, smaller cyclic shift intervals are used to multiplex more signals. When channel conditions deteriorate, the cyclic shift interval is increased to reduce inter-code interference, thus optimizing the trade-off between signal capacity and interference levels
Solution Approach 2:
The patent introduces dynamic adaptation by making the cyclic shift interval configurable and adjustable rather than fixed. The system can dynamically select appropriate cyclic shift intervals based on channel quality, signal conditions, and interference levels, enabling the code-multiplexing system to adapt to varying operational conditions
2Productivity
If the cyclic shift interval between CCEs for CQI and ACK/NACK signals is reduced to increase resource utilization, then resource efficiency improves, but signal separability deteriorates
Solution Approach 1:
The patent changes the cyclic shift interval parameter to optimize the balance between resource utilization and signal separability. By adjusting this parameter, the system can achieve better resource efficiency while maintaining sufficient signal separability for reliable detection of CQI and ACK/NACK signals
3Quantity of substance
If ZC sequences with adjacent cyclic shift values are used to maximize code-multiplexing capacity, then the number of separable signals increases, but interference between adjacent sequences increases
Solution Approach 1:
The patent applies local quality by assigning different cyclic shift intervals to different signal types or different resource regions. Instead of using a uniform cyclic shift interval across all signals, the system can apply larger intervals to signals that are more susceptible to interference while using smaller intervals where interference is less critical, thus optimizing both capacity and interference management
Data Source
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AI summary
Provided is a radio communication device which can suppress inter-code interference between an ACK/NACK signal and a CQI signal which are code-multiplexed. In this device, a diffusion unit (214) diffuses the ACK/NACK signal inputted from a judgment unit (208) by using a ZC sequence. A diffusion unit (219) diffuses the CQI signal by using a cyclic shift ZC sequence. By using a Walsh sequence, a diffusion unit (216) further diffuses the ACK/NACK signal which has been diffused by using the ZC sequence. A control unit (209) controls the diffusion unit (214), the diffusion unit (216), and the diffusion unit (219) so that the minimum value of the difference between the CQI signals from a plurality of mobile stations and a cyclic shift amount of the ACK/NACK signal is not smaller than the minimum value of the difference between the cyclic shift amounts of the ACK/NACK signals from the plurality of mobile stations.