PDSCH Power Offset Determination for Interference Mitigation
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Solution Overview
Problem
In LTE-A wireless networks, inter-cell interference limits network capacity, and existing interference mitigation techniques are inadequate, particularly in scenarios where user equipment (UE) with varying distances from the base station require efficient power offset determination for multi-user superposition transmission.
Innovation Solution
The implementation of non-orthogonal multiplexing schemes, such as multi-user superposition transmission, where the base station uses higher layer signaling to provide power offset information for both serving and co-scheduled Physical Downlink Shared Channels (PDSCH) to UEs, allowing UEs to detect and suppress intra-cell interference by determining power offsets and modulation orders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If non-orthogonal multiplexing schemes are used to improve spectral efficiency, then spectral efficiency is improved, but interference between co-scheduled UEs increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting power offset values for co-scheduled UEs based on their channel conditions, distances from the eNB, and modulation orders. This allows the system to optimize spectral efficiency while controlling interference by changing the power allocation parameter rather than maintaining fixed orthogonal resources.
Solution Approach 2:
The patent implements dynamics by enabling UEs to detect and suppress interfering signals in real-time through iterative interference cancellation processes. The system adaptively adjusts power offsets and modulation schemes based on detected interference levels, transforming the static orthogonal multiplexing into a dynamic non-orthogonal scheme that manages interference actively.
2Reliability
If power offset information is provided through higher layer signaling to enable interference suppression, then interference suppression capability is improved, but signaling overhead increases
Solution Approach 1:
The patent segments the power offset information into discrete levels that can be efficiently signaled through higher layer signaling. Instead of transmitting continuous power values, the system divides power offsets into manageable segments or levels, reducing the amount of signaling required while still providing sufficient granularity for effective interference suppression.
Solution Approach 2:
The patent applies partial action by providing power offset information only when non-orthogonal multiplexing is actually deployed and when co-scheduling is utilized. The signaling is conditional and targeted, avoiding unnecessary overhead in scenarios where interference suppression is not needed, thus balancing reliability improvement with overhead minimization.
3Productivity
If UEs are distributed across varying distances from the eNB to serve more users, then network capacity is improved, but distance disparity causes unequal signal quality
Solution Approach 1:
The patent applies local quality by tailoring the power offset allocation and modulation scheme selection to each UE's specific channel conditions and distance from the eNB. Closer UEs receive different power offsets and modulation orders compared to farther UEs, optimizing each user's signal quality locally rather than applying a uniform scheme across all users, thereby maintaining capacity while improving signal quality consistency.
Data Source
AI summary
Examples include techniques for determining power offsets of a physical downlink shared channel (PDSCH). In some examples higher and physical layer signaling may be provided to user equipment (UE) by a base station such as an evolved Node B to enable the UE to determine power offset values for a multiplexed PDSCH having a serving PDSCH and a co-scheduled PDSCH transmitted via use of same time and frequency resources. The determined power offset values for use by the UE to demodulate the serving PDSCH and mitigate possible interference caused by the co-scheduled PDSCH. Both the UE and the eNB may operate in compliance with one or more 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) standards.