NLOS Wireless Backhaul Uplink Framing for Low-BER Small Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing cell density in radio access networks leads to non-line-of-sight (NLOS) wireless backhaul channels, which existing point-to-point line-of-sight wireless backhaul communication mechanisms are not suitable for, due to higher density and different requirements such as lower latency and bit error rate.
Innovation Solution
A method and apparatus for NLOS wireless backhaul communication that includes generating and transmitting uplink data frames using forward error correction encoding, Reed Solomon encoding, byte interleaving, Turbo encoding, and Single Carrier-Frequency Division Multiple Access (SC-FDMA) modulation, along with a transmitter system that performs Discrete Fourier Transform precoding and sub-carrier mapping to ensure reliable communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If point-to-point line-of-sight wireless backhaul communication mechanisms are used, then communication reliability is maintained, but the system becomes unsuitable for densely populated small cell backhauls with non-line-of-sight channels
Solution Approach 1:
The patent changes the fundamental transmission parameters from LOS-optimized single carrier waveforms to NLOS-suited SC-FDMA waveforms with cyclic prefixes. This includes modifying the signal structure to handle multipath propagation, changing the frequency spectrum utilization, and adjusting the equalization approach to maintain reliability in NLOS conditions.
Solution Approach 2:
The system dynamically adapts to NLOS channel conditions by implementing time-varying equalization and adaptive resource allocation. The SC-FDMA structure allows dynamic handling of multipath components through cyclic prefix adjustment and time-frequency resource management, enabling the system to maintain reliability despite changing propagation conditions.
2Productivity
If cell density is increased to meet growing demand for voice and data services, then service capacity is improved, but wireless backhaul communication becomes unsuitable due to NLOS conditions
Solution Approach 1:
The patent implements parameter changes in the physical layer waveform structure, transitioning from traditional single carrier to SC-FDMA with cyclic prefixes. This enables the system to handle the higher density of NLOS backhaul links by providing robustness against multipath fading and interference, thus maintaining reliability while supporting increased service capacity.
Solution Approach 2:
The patent segments the backhaul network into small cell units, each with its own SC-FDMA optimized transmission. This segmentation allows independent optimization of each backhaul link, enabling the overall network to achieve high capacity while maintaining individual link reliability through NLOS-appropriate waveforms.
3Device complexity
If single carrier waveforms with time-domain equalization are used for LOS backhaul, then transmission simplicity is maintained, but the system fails to meet lower latency and bit error rate requirements of NLOS small cell backhauls
Solution Approach 1:
The patent changes the waveform parameter from simple single carrier to SC-FDMA with cyclic prefix, which initially appears more complex but actually reduces latency by enabling more efficient time-frequency resource utilization. The cyclic prefix structure allows for better synchronization and reduced inter-symbol interference, thereby reducing effective transmission latency despite the added structural complexity.
4Device complexity
If single carrier waveforms with time-domain equalization are used for LOS backhaul, then transmission simplicity is maintained, but bit error rate performance deteriorates in NLOS conditions
Solution Approach 1:
The patent applies parameter changes to the waveform structure by introducing SC-FDMA with cyclic prefixes, which fundamentally improves bit error rate performance in NLOS conditions. The cyclic prefix acts as a guard interval that prevents inter-symbol interference from multipath propagation, while the SC-FDMA structure provides frequency diversity that reduces the impact of deep fades, thereby significantly improving BER without excessive complexity.
Data Source
AI summary
A method for uplink (UL) wireless backhaul communication at a wireless backhaul remote unit in a radio access network comprising receiving a configuration for radio frames and a transmission schedule through a downlink (DL) physical layer broadcast channel, wherein the transmission schedule comprises a transmission allocation for the remote unit, generating a UL data frame, wherein generating the UL data frame comprises performing forward error correction (FEC) encoding on a data bit stream to generate a plurality of FEC codewords, wherein performing the FEC encoding comprises performing Reed Solomon (RS) encoding on the data bit stream to generate a plurality of RS codewords, performing byte interleaving on the RS codewords, and performing Turbo encoding on the byte interleaved RS codewords to generate one or more Turbo codewords, wherein each Turbo codeword is encoded from more than one RS codeword, and transmitting the UL data frame according to the transmission allocation.