Multidimensional Wireless Codebooks for Pilotless Short-Packet Decoding
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Solution Overview
Problem
Current communication technologies face challenges in rapidly changing channels due to resource-intensive channel estimation and imperfect acquisition, particularly in scenarios like Ultra-Reliable Low-Latency Communication (URLLC) and machine type communications (MTC), leading to significant rate losses and demodulation errors.
Innovation Solution
A transmitter and receiver system uses a multidimensional codebook generated with prime factors and orthogonal sets of vectors to enable pilotless transmission of information bits, maximizing chordal distances between codewords for efficient decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pilot symbols are time- and/or frequency-division multiplexed with information-bearing symbols to provide channel estimation, then channel estimation accuracy is improved, but resource efficiency deteriorates due to reserved time and frequency resources
Solution Approach 1:
The invention extracts and removes the pilot symbols from the transmission system, replacing them with a codebook-based approach where information bits are directly encoded into codewords. This eliminates the need for separate channel estimation resources while maintaining transmission reliability through the inherent structure of the codebook designed for specific channel conditions
Solution Approach 2:
The codebook is pre-generated and stored at both transmitter and receiver before actual data transmission. This preliminary preparation allows the system to skip real-time channel estimation and directly perform decoding operations, significantly reducing resource overhead and latency
2Measurement precision
If pilot transmission periodicity is increased to handle rapidly changing channels, then channel estimation quality is improved, but resource consumption increases
Solution Approach 1:
The invention completely removes the periodic pilot transmission mechanism from the system. Instead of sending pilots at regular intervals to track channel variations, the system uses a codebook that is预先 designed for specific channel conditions, eliminating the need for continuous channel probing and reducing energy consumption
3Reliability
If traditional channel estimation training is used for short-packet transmissions, then channel information is acquired, but rate losses increase due to resource-intensive training overhead
Solution Approach 1:
The codebook is pre-computed and stored at both transmitter and receiver before short-packet transmission. This preliminary action eliminates the need for real-time channel estimation training during the actual data transmission, allowing immediate encoding and decoding operations that maximize transmission rate while maintaining reliability through the codebook structure
Solution Approach 2:
The codebook-based system is self-sufficient and does not require external pilot signals or channel estimation assistance from the receiver. The transmitter independently encodes information using the pre-generated codebook, and the receiver independently decodes using the same codebook, eliminating the interactive training process and its associated rate losses
Data Source
AI summary
A wireless transmitter, receiver and a method of wireless communication, the method including obtaining prime factors for a number NRE of time-frequency resources, including at least two different prime factors, generating a codebook comprising at least one codeword, each of the at least one codeword being generated by multiplying at least one mask sequence with one vector of an orthogonal set of vectors, and each mask sequence of the at least one mask sequence being obtained from an exponentiation operation involving a base and an exponent, the base being defined by the at least two different prime factors, and the exponent being defined by a quadratic polynomial having a number of m variables, where m is equal to a total number of the prime factors constituting NRE, and providing, to a receiver, information bits in at least one of the at least one codeword over the NRE time-frequency resources.