Variable Observation Length Equalizer for Non-Orthogonal Multicarrier Signals
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Solution Overview
Problem
The QAM-FBMC transmission scheme faces a bottleneck in SINR value, particularly when high-order modulation is used, leading to increased noise ratio due to Inter-Symbol Interference (ISI), while maintaining low transceiver complexity is a challenge.
Innovation Solution
A method is introduced to vary the observation length for signal transmission and reception in a filter bank multicarrier system using non-orthogonal transmission signals, allowing for efficient signal processing with a new equalizer structure that extends observation length as an integer multiple of the symbol length without increasing transceiver complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the observation length is lengthened to improve SINR performance in high-order modulation, then the SINR value increases, but the receiver complexity increases
Solution Approach 1:
The patent applies dynamics by making the observation length variable rather than fixed. The equalizer adapts the observation length based on channel conditions and modulation schemes, allowing the system to optimize between SINR performance and receiver complexity dynamically. This resolves the contradiction by enabling long observation lengths only when necessary for high-order modulation, while using shorter lengths for simpler scenarios.
Solution Approach 2:
The patent changes the parameter of observation length from a static value to a variable parameter that can be adjusted according to channel state information and modulation order. This allows the system to adapt the observation length to match the specific requirements of each transmission scenario, improving SINR when needed while avoiding unnecessary complexity increase in other cases.
2Productivity
If high-order modulation is used to increase data transmission rate, then the productivity increases, but the noise ratio increases due to ISI
Solution Approach 1:
The patent applies preliminary action by performing channel estimation and equalization using extended observation lengths before data detection. The equalizer uses pilot symbols and channel state information to pre-compensate for ISI effects before the actual data symbols are decoded, thereby enabling high-order modulation to achieve high data rates without suffering from excessive noise ratio due to ISI.
Solution Approach 2:
The patent replaces simple detection mechanisms with an advanced equalization system that uses channel state information and variable observation lengths. This substitution of the detection mechanism allows the system to handle high-order modulation by compensating for ISI effects through sophisticated signal processing rather than relying on simple threshold detection that would be overwhelmed by noise.
Data Source
AI summary
The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). A method and apparatus for transmitting and receiving signals using a variable observation length in a multi-carrier system using the non-orthogonal transmission signal. A receiver performs fast Fourier transform on reception vectors contained in the signal, equalizes the fast Fourier transformed reception vectors by a 1-tap zero forcing equalizer, and applies a reception filter based on the observation length to the equalized reception vectors. A transmitter includes a transceiver configured to transmit and receive a signal, and a controller configured to cause the transceiver to transmit an indicator for a Modulation and Coding Scheme (MCS) level to a receiver based on a channel state, and transmit a signal applied with the MCS level to the receiver.