NLOS Wireless Backhaul Downlink Framing for Dense Small Cells
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Solution Overview
Problem
The increasing cell density in radio access networks leads to non-line-of-sight (NLOS) wireless backhaul channels, which require efficient communication mechanisms to manage higher traffic loads and maintain low latency and error rates, as traditional point-to-point line-of-sight wireless backhaul links are insufficient for dense small cell environments.
Innovation Solution
A method for NLOS wireless backhaul communication that employs a radio frame with adjustable link directionality, using time-frequency multiplexing and single carrier block transmission with Discrete Fourier Transform (DFT) spreading for frequency diversity, along with Reed Solomon and Turbo encoding for error correction, to balance traffic load and ensure low latency and error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cell density is increased to meet growing demand for voice and data services, then service capacity and coverage are improved, but traditional point-to-point line-of-sight wireless backhaul communication mechanisms become insufficient
Solution Approach 1:
The patent implements dynamic TDD configuration that allows the system to adaptively adjust the ratio of uplink to downlink time slots based on real-time traffic conditions. This dynamic adjustment enables the backhaul link to handle varying traffic loads efficiently, resolving the contradiction between increased service capacity and maintained communication reliability in dense small cell environments
Solution Approach 2:
The system changes key transmission parameters including time slot allocation ratios, subcarrier spacing, and modulation schemes to optimize performance for NLOS conditions. By adjusting these parameters dynamically, the system maintains reliable backhaul communication while supporting higher cell density and service capacity
2Device complexity
If single carrier waveforms with time-domain equalization are used for LOS wireless backhaul, then transmission simplicity is maintained, but the system becomes unsuitable for dense small cell NLOS environments
Solution Approach 1:
The patent employs dynamic TDD configuration that adapts time slot allocation between uplink and downlink based on traffic conditions and channel characteristics. This dynamic adjustment enables the system to maintain operational simplicity while becoming adaptable to dense small cell NLOS environments where traffic patterns and channel conditions vary significantly
Solution Approach 2:
The system designs a unified transmission framework that can operate in both LOS and NLOS conditions, as well as adapt to different traffic loads and cell densities. This multi-functional approach allows single carrier waveforms to serve multiple purposes and environments without requiring completely different transmission mechanisms
3Productivity
If traffic load balancing is implemented with adjustable link directionality ratio, then uplink and downlink throughput are optimized, but time-frequency resource allocation complexity increases
Solution Approach 1:
The system implements dynamic adjustment of the link directionality ratio, which determines the proportion of time slots allocated to uplink versus downlink transmissions. This dynamic ratio adjustment enables optimized traffic throughput for varying load conditions while the patent manages the associated complexity through systematic resource allocation algorithms and standardized frame structures
Data Source
AI summary
A method for communicating over a wireless backhaul channel comprising generating a radio frame comprising a plurality of time slots, wherein each time slot comprises a plurality of symbols in time and a plurality of sub-carriers in a system bandwidth, broadcasting a broadcast channel signal comprising a transmission schedule to a plurality of remote units in a number of consecutive sub-carriers centered about a direct current (DC) sub-carrier in at least one of the time slots in the radio frame regardless of the system bandwidth, and transmitting a downlink (DL) control channel signal and a DL data channel signal to a first of the remote units, wherein the DL data channel signal is transmitted by employing a single carrier block transmission scheme comprising a Discrete Fourier Transform (DFT) spreading for frequency diversity.