Precoder for Spatial Multiplexing Using Predetermined Sequences
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Solution Overview
Problem
Existing MIMO systems face challenges with closed-loop precoding in high mobility situations due to outdated channel feedback, and open-loop precoder cycling leads to increased computational complexity and non-uniform energy distribution, affecting interference rejection and spectral efficiency.
Innovation Solution
The method involves using a predetermined precoder sequence with a short uniformly varying precoding sequence (SUVPS) that cycles through a fixed set of precoding filters known to both transmitter and receiver, optimizing energy distribution and reducing computational complexity by reusing computations across different ranks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If closed loop precoding is used to match channel characteristics, then transmission performance is improved, but system complexity and feedback overhead increase
Solution Approach 1:
The patent changes the parameter of precoding from channel-dependent (closed-loop) to channel-independent (open-loop) by using a predetermined precoder sequence. This eliminates the need for channel feedback while maintaining transmission performance through carefully designed precoder sequences that work effectively across various channel conditions.
2Stability of the object's composition
If precoder cycling is used to distribute energy uniformly, then spatial distribution is improved, but computational complexity increases
Solution Approach 1:
The patent implements periodic action by using a predetermined precoder sequence that cycles through a fixed set of precoding filters. This periodic cycling distributes energy uniformly across spatial dimensions while maintaining manageable computational complexity through the structured, repeating pattern of the precoder sequence.
Solution Approach 2:
The patent applies preliminary action by pre-defining the precoder sequence at the transmitter before transmission. This predetermined sequence is known to both transmitter and receiver, allowing the receiver to prepare appropriate combining filters in advance, thereby reducing real-time computational complexity while achieving uniform energy distribution.
3Reliability
If codebook-based precoders are used for channel dependent precoding, then channel matching is improved, but energy distribution uniformity deteriorates
Solution Approach 1:
The patent inverts the conventional approach by abandoning channel-dependent codebook-based precoding in favor of channel-independent predetermined precoder sequences. This inversion achieves uniform energy distribution across the MIMO channel while maintaining transmission reliability through carefully designed sequences that are robust to channel variations.
Data Source
AI summary
A method of spatially precoding data includes determining a transmission rank of a communication channel and selecting a set of one or more precoding filters derived from a single generator matrix based on said transmission rank. The method also includes precoding data for transmission to a remote device using said precoding filters in a predetermined order according to a predetermined precoding sequence. The precoding may include using different ones of said precoding filters during different precoding intervals in a predetermined precoding period of the predetermined precoding sequence. Additionally, precoding data for transmission may involve traversing an Orthogonal Frequency Division Multiplexing (OFDM) resource block in an alternating pattern during said predetermined precoding period.