Frequency Domain OFDM Backhaul Transmission for Latency Reduction
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Solution Overview
Problem
Conventional BBU plus RRU architectures in OFDM systems face high I/Q transmission rate and bandwidth demands, leading to increased latency and synchronization issues, especially with wider bands and multiple antennas, making efficient data transmission and reception challenging, particularly in complex backhaul networks.
Innovation Solution
The method involves selecting a set of frequency bands in the OFDM system for data transmission and reception, allowing data to be communicated in the frequency domain instead of the time domain, which reduces data traffic on the backhaul and alleviates latency issues by optimizing frequency resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If time domain I/Q data transmission is used in conventional BBU plus RRU architecture, then data can be transmitted between nodes, but transmission rate and bandwidth requirements become excessively high
Solution Approach 1:
The patent transforms the transmission domain parameter from time domain to frequency domain. By performing FFT processing at the BBU to convert time domain I/Q data into frequency domain complex symbols, and transmitting these frequency domain data to RRU, the system achieves the same data transmission capability with significantly reduced transmission rate and bandwidth requirements.
2Adaptability or versatility
If more receive antennas are deployed for MIMO application, then spatial freedom and data rates are improved, but backhaul transmission rate requirement increases significantly
Solution Approach 1:
The patent applies frequency domain transformation to MIMO backhaul transmission. By converting time domain I/Q data from multiple antennas into frequency domain complex symbols through FFT, the system maintains full MIMO spatial freedom and data rate capabilities while reducing the backhaul transmission rate requirement by a factor of 2 (since complex symbols contain twice the information density of time domain samples).
3Device complexity
If a router-like device is deployed to connect BBU with multiple RRUs, then network economy is improved, but latency becomes large and uncontrollable
Solution Approach 1:
The patent implements frequency domain data transmission between BBU and RRU, which reduces the data volume requiring transmission through the backhaul network. This parameter change in transmission domain enables the system to maintain low latency even when router-like devices are deployed to connect BBU with multiple RRUs economically, as the reduced data throughput requirement allows for more predictable and controllable latency characteristics.
Data Source
AI summary
Embodiments of the disclosure provide a method in a source node for transmitting data in an OFDM system in which data are transmitted on frequency bands from the source node to a destination node, the method comprising: selecting a set of frequency bands from available frequency bands in the OFDM system; and transmitting data in frequency domain on the selected set of frequency bands to the destination node. Embodiments of the disclosure further provide a method at a destination node for receiving data in an OFDM system in which data are received on frequency bands from a source node, the method comprising: determining a set of frequency bands of available frequency bands on which data are to be received in frequency domain; and receiving the data on the determined set of frequency bands from the source node. Corresponding apparatuses are also provided.