SC-FDMA Code Division Multiplexing for Wireless Data Transmission
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Solution Overview
Problem
There is a need for efficient transmission techniques in multiple-access systems, particularly for transmitting different types of data such as traffic, signaling, and pilot data in wireless communication systems, where existing methods do not adequately optimize data transmission efficiency.
Innovation Solution
The use of single-carrier frequency division multiple access (SC-FDMA) techniques, including interleaved FDMA (IFDMA), localized FDMA (LFDMA), and enhanced FDMA (EFDMA), which apply code division multiplexing (CDM) to traffic, signaling, and pilot data, allowing for efficient transmission across frequency subbands and symbol periods, and employing spreading codes and scrambling to enhance data recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If code division multiplexing is applied to multiple data types on overlapping time-frequency resources, then system capacity and transmission efficiency are improved, but interference management and signal recovery complexity increase
Solution Approach 1:
The patent segments different types of data (traffic data, signaling, pilot) and assigns them different spreading codes and time-frequency resources. This segmentation allows multiple data types to be transmitted simultaneously over overlapping resources while maintaining distinguishability through code division multiplexing, thereby increasing system capacity without causing unmanageable interference
Solution Approach 2:
The patent changes the code domain parameters by assigning different spreading codes (such as Walsh-Hadamard codes) to different data types and users. This parameter change in the code domain enables orthogonal or near-orthogonal separation of signals, allowing the receiver to recover individual data streams from composite signals through correlation processing, thus managing signal recovery complexity
2Productivity
If signaling and pilot data are transmitted efficiently with reduced overhead, then transmission efficiency is improved, but data rate and reliability requirements become more stringent
Solution Approach 1:
The patent merges signaling and pilot data transmission with traffic data transmission by applying code division multiplexing. Instead of transmitting signaling and pilot separately as overhead, the system combines all data types into a single multiplexed transmission using different spreading codes, thereby reducing overhead and improving transmission efficiency while maintaining reliability through the robustness of CDM
Solution Approach 2:
The patent uses spreading codes to create coded versions of the original data signals. Each data type is copied and spread with a unique code, allowing the receiver to recover the original data through correlation. This copying mechanism enables efficient transmission of signaling and pilot data with reduced overhead while maintaining the ability to reliably recover the original signals
Data Source
AI summary
In a single-carrier frequency division multiple access (SC-FDMA) system that utilizes interleaved FDMA (IFDMA) or localized FDMA (LFDMA), a transmitter generates modulation symbols for different types of data (e.g., traffic data, signaling, and pilot) and performs code division multiplexing (CDM) on at least one data type. For example, the transmitter may apply CDM on signaling and/or pilot sent on frequency subbands and symbol periods that are also used by at least one other transmitter. To apply CDM to a given data type (e.g., signaling), the transmitter performs spreading on the modulation symbols for that data type with an assigned spreading code. CDM may be applied across symbols, samples, samples and symbols, frequency subbands, and so on. The transmitter may perform scrambling after the spreading. The transmitter generates SC-FDMA symbols of the same or different symbol durations for traffic data, signaling, and pilot and transmits the SC-FDMA symbols.