Downlink Uplink Multiplexing Wide Frequency Spacing
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Solution Overview
Problem
Current wireless communication systems, particularly 4G LTE and Wi-Fi networks, face inefficiencies due to interference and synchronization requirements in time division duplex (TDD) and frequency division duplex (FDD) methods, leading to delays, increased costs, and resource wastage from guard times and bands.
Innovation Solution
Downlink and uplink data are multiplexed on widely spaced frequencies, allowing concurrent transmission and reception without guard time intervals or complex filters, improving system latency and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time division duplex (TDD) is used to separate downlink and uplink transmissions, then interference between downlink and uplink signals is avoided, but transmission delay increases due to required synchronization and guard time intervals
Solution Approach 1:
The system segments the frequency spectrum into widely separated downlink and uplink frequency bands, allowing simultaneous transmission without interference. By dividing the spectrum into distinct, widely spaced segments rather than using time segmentation, the system achieves both interference avoidance and continuous transmission.
Solution Approach 2:
The patent transitions from time-domain separation (TDD) to frequency-domain separation with wide spacing (enhanced FDD). This dimensional change in the separation approach allows concurrent transmissions by exploiting the frequency dimension more effectively, eliminating the need for time synchronization and guard intervals.
2Productivity
If frequency division duplex (FDD) with closely spaced frequencies is used to enable concurrent transmission, then transmission efficiency improves, but receiver overload occurs due to transmitter output interference
Solution Approach 1:
The system changes the frequency spacing parameter from close spacing to wide spacing between downlink and uplink bands. This parameter change maintains the benefit of concurrent transmission while eliminating receiver overload by ensuring sufficient frequency separation to prevent transmitter output from interfering with receiver input.
3Reliability
If widely spaced frequencies are used for downlink and uplink to prevent receiver overload, then interference is reduced, but system cost increases due to required high-complexity multi-pole filters
Solution Approach 1:
By optimizing the frequency spacing parameter to a specific wide separation range, the patent achieves interference reduction with moderate filter complexity. The wide spacing naturally reduces interference, allowing the use of simpler filters compared to closely spaced FDD systems, thus resolving the contradiction between interference reduction and device complexity.
4Reliability
If guard time intervals are implemented in TDD systems to account for propagation delays, then synchronization is maintained, but system resources are wasted
Solution Approach 1:
The patent switches from time-domain resource allocation (requiring guard times) to frequency-domain resource allocation with wide spacing. This allows simultaneous uplink and downlink transmissions without guard intervals, eliminating the time resource waste while maintaining reliability through frequency separation.
Data Source
AI summary
Methods and systems for multiplexing downlink and uplink data on widely spaced frequencies are disclosed. The method of multiplexing downlink and uplink data packets for providing wireless broadband link between a base station and a plurality of client devices includes transmitting a first data packet by the base station to a first client device at a downlink frequency during a first time interval. The method includes receiving a second data packet by the base station from a second client device at an uplink frequency during a second time interval, wherein the base station concurrently transmits at least a portion of the first data packet to the first client device and receives at least a portion of the second data packet from the second client device, and wherein there is a wide separation between the downlink frequency and the uplink frequency.