Wideband LTE Uplink Subcarrier Interleaving for Coverage
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Solution Overview
Problem
Current LTE uplink transmissions face challenges in wideband frequency bands due to increased propagation path loss and smaller coverage areas, leading to reduced energy transmission for physical Uplink Control Channel (PUCCH) messages, especially when deep fading occurs and uplink beamforming is ineffective.
Innovation Solution
A method and device for wideband LTE uplink transmission that involves scheduling non-contiguous subcarriers for user equipment (UE) using single carrier frequency division multiple access (SC-FDMA), with subcarriers interleaved and separated by fixed spacing, allowing for efficient PUCCH and PUSCH transmissions, and utilizing predefined mapping rules and signaling for subcarrier location and number determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If higher frequency bands (3.5 GHz-6 GHz) are used for cellular communication, then larger contiguous bandwidth (up to 400 MHz) is available, but propagation path loss increases and coverage area decreases
Solution Approach 1:
The wideband frequency spectrum is divided into multiple subbands, with each subband assigned to different user equipments (UEs). This segmentation allows the system to utilize the full available bandwidth while maintaining reliable coverage by distributing UEs across different frequency segments, thereby mitigating the path loss issue at higher frequencies.
2Quantity of substance
If unpaired frequency bands are used, then larger contiguous bandwidth is available, but only one band can be used for transmission and reception at a time
Solution Approach 1:
The unpaired frequency band is segmented into multiple subbands that can be flexibly allocated for different transmission directions (uplink and downlink) at different time resources. This allows the system to achieve full-duplex communication capabilities by time-division multiplexing across segmented frequency resources.
3Reliability
If non-contiguous subcarriers are allocated for SC-FDMA transmission, then frequency diversity is improved, but subcarrier interleaving complexity increases
Solution Approach 1:
The frequency spectrum is divided into multiple subbands, and subcarriers are allocated in a segmented manner across these subbands. This segmentation provides frequency diversity by spreading subcarriers across different frequency regions while using systematic interleaving patterns that manage the complexity of non-contiguous subcarrier allocation.
4Reliability
If uplink beamforming is used to combat deep fading, then signal strength is improved, but effectiveness is reduced in wideband frequency bands with path loss
Solution Approach 1:
The system segments the uplink transmission across multiple subbands rather than concentrating energy in a single beamformed direction. This segmented approach provides frequency diversity that combats deep fading more effectively than beamforming alone in wideband scenarios, reducing the energy required to maintain reliable signal strength across the entire bandwidth.
Data Source
AI summary
A method for receiving wideband (WB) LTE uplink signals. A base station may signal a first frequency tone assignment to a first user equipment (UE), the first frequency tone assignment scheduling at least a first set of subcarriers allocated to the first UE, subcarriers in the first set of subcarriers being non-contiguous in the frequency domain. Subcarriers in the first set of subcarriers may be interleaved with subcarriers in a second set of subcarriers. The first UE may perform a first single carrier frequency division multiple access (SC-FDMA) uplink transmission over the first set of subcarriers. A second UE may perform a second SC-FDMA uplink transmission, the second SC-FDMA uplink transmission spanning the second set of subcarriers.