Adaptive Frame Design for Wireless Channel Estimation
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Solution Overview
Problem
Fixed frame structures in massive MIMO wireless communication systems waste resources by allocating equal time for channel estimation across all UEs, regardless of their mobility, leading to inefficient use of resources as static UEs' channels change infrequently.
Innovation Solution
An adaptive frame design that allocates resource elements based on the validity time of each UE's channel estimate, reusing valid estimates across multiple frames and reallocating resources for data transmission, allowing the base station to decide when channel estimation is necessary based on UE mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed frame structure is used to allocate resources for channel estimation, then channel estimation can be performed regularly for all UEs, but resources are wasted on static UEs whose channels do not change frequently
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed frame structure to a dynamic adaptive frame structure. The base station determines whether channel estimation is needed for each UE based on mobility state information and validity time assessments. This allows the system to adapt resource allocation dynamically - performing channel estimation only when necessary for mobile UEs while skipping it for static UEs with valid channel estimates, thus eliminating resource wastage while maintaining estimation accuracy when required
Solution Approach 2:
The patent changes the parameter of frame structure from fixed to adaptive. By introducing validity time parameters and mobility state parameters, the system can adjust the channel estimation frequency per UE based on their specific conditions. The base station modifies the resource allocation parameters dynamically - allocating pilot signals only to UEs whose channel estimates have expired or are invalid, rather than using a uniform fixed allocation for all UEs
2Loss of information
If channel estimation is performed for every frame for all UEs, then up-to-date channel information is available, but network throughput decreases due to reduced resources for data transmission
Solution Approach 1:
The patent applies partial action by performing channel estimation only for the subset of UEs that require it, rather than for all UEs in every frame. The base station identifies UEs with expired or invalid channel estimates and performs estimation only for those. This partial approach maintains channel information freshness for mobile UEs while avoiding excessive estimation actions on static UEs, thereby freeing resources for data transmission and improving network throughput
Solution Approach 2:
The patent implements feedback mechanisms where the base station assesses the validity time of channel estimates and determines mobility states of UEs. This feedback information is used to make intelligent decisions about whether channel estimation is needed. The system continuously monitors channel estimate validity and adjusts estimation frequency accordingly, ensuring channel information remains fresh while optimizing resource usage for data transmission based on actual channel conditions
3Ease of operation
If a fixed number of resource elements are dedicated to pilot transmission, then channel estimation can be performed consistently, but the frame structure cannot adapt to UE mobility variations
Solution Approach 1:
The patent transforms the static fixed frame structure into a dynamic adaptive frame structure. The base station evaluates mobility state information and channel estimate validity for each UE and adjusts pilot signal allocation dynamically. This allows the system to maintain simple operation for static UEs (no estimation needed) while adapting to mobile UEs (estimation performed when needed), achieving both ease of operation and mobility adaptability simultaneously
Solution Approach 2:
The patent applies local quality by treating different UEs differently based on their individual mobility characteristics and channel estimate validity. Instead of applying a uniform frame structure to all UEs, the base station performs local assessments for each UE and allocates pilot signals only where needed. This localized approach allows the system to maintain simplicity for static UEs while providing adaptability for mobile UEs, optimizing both operational ease and mobility handling
Data Source
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AI summary
Aspects and embodiments provide a method of allocating frame resource elements in a wireless communication network for the purpose of channel estimation, and a base station and computer program product operable to perform that method. The method comprises: determining a channel estimate associated with each user equipment to be scheduled in a given frame, assessing whether a validity time associated with each currently available channel estimation value, e.g. CSI, associated to each user equipment is still valid or should be considered as expired; and allocating the frame resource elements to either channel estimation, when the current channel estimation value is not anymore valid, or else to data transmission, when it is still valid. The validity time comprises a number of frames and is selected accoding to an associated mobility of the user equipment, wherein for semi-static UEs the current channel estimation is considered to be valid for a longer time. Aspects and embodiments may provide a method for an adaptive and user-centric frame design in massive MIMO which takes into account mobility of UEs and thus may mitigate waste of resource associated with use for unnecessary channel estimation purposes.