Base Station Transmitter Phase Diversity for Multiuser Diversity
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Solution Overview
Problem
Conventional technologies fail to adequately achieve multiuser diversity effect in rf signal transmission due to the location-dependent assignment of slots to mobile terminal units.
Innovation Solution
A processing apparatus in a base station that transmits data through multiple antennas by providing different cyclic delays and initial phases to each region, ensuring that the initial phases differ between adjacent regions, thereby enhancing the multiuser diversity effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blocks are distributed in a broader frequency region to achieve frequency diversity effect, then signal reception robustness is improved, but multiuser diversity effect cannot be adequately achieved
Solution Approach 1:
The patent applies different frequency allocation strategies to different users based on their channel conditions. Specifically, some users are assigned blocks distributed in broader frequency regions to achieve frequency diversity, while other users are assigned blocks in narrower frequency regions to achieve multiuser diversity. This local differentiation resolves the contradiction by allowing each user to benefit from the appropriate diversity effect based on their specific reception environment.
Solution Approach 2:
The patent dynamically adjusts the frequency allocation strategy based on channel conditions and user locations. The base station determines whether to apply frequency diversity or multiuser diversity schemes adaptively, switching between different block distribution patterns. This dynamic approach allows the system to optimize for signal robustness when needed while maintaining multiuser diversity benefits when conditions permit.
2Productivity
If blocks are distributed in a narrower frequency region to achieve multiuser diversity effect, then transmission efficiency for unicast signals is improved, but frequency diversity effect is reduced
Solution Approach 1:
The patent implements user-specific frequency allocation where users with good channel conditions and favorable locations are assigned narrow frequency blocks to achieve multiuser diversity and high transmission efficiency. Users with poor channel conditions or unfavorable locations are assigned broad frequency blocks to ensure frequency diversity and reliable reception. This local quality differentiation resolves the contradiction by matching the diversity scheme to each user's specific situation.
Solution Approach 2:
The system dynamically selects between narrow and broad frequency block allocations based on real-time channel conditions, user locations, and base station load. This dynamic adaptation allows the system to maximize transmission efficiency when multiuser diversity conditions are favorable while ensuring frequency diversity protection when needed, thus resolving the productivity-reliability tradeoff.
3Device complexity
If the same initial phase is used for all regions, then system complexity is reduced, but multiuser diversity effect is not adequately achieved
Solution Approach 1:
The patent applies different initial phases to different frequency regions based on user assignments and channel conditions. Users assigned to specific regions receive signals with initial phases optimized for their location and channel characteristics. This local differentiation of initial phases enhances multiuser diversity effect by creating distinct signal characteristics for different users, resolving the contradiction between system simplicity and diversity performance.
Solution Approach 2:
The system changes the initial phase parameter across different frequency regions and time slots to optimize multiuser diversity. By varying this parameter adaptively rather than keeping it constant, the system achieves better user differentiation and diversity benefits. This parameter change approach resolves the contradiction by demonstrating that controlled complexity in parameter variation yields significant performance improvements.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
A processing apparatus used in a base station operable to transmits data to a mobile unit through a plurality of antennas using regions defined by frequency and time axes. The apparatus provides the data to be transmitted with a delay different from each other according to cyclic delay for each of outputs of the antennas and with one of a plurality of initial phases (p1, p2) for each of the regions, the one of the initial phases being switched in frequency domain and/or time domain. The one of the initial phases for the each of the regions is different from other of the initial phases for at least one of neighboring regions the neighboring regions being adjacent to the each of the regions.