Spread-Spectrum Receiver Code Acquisition Using Multi-Bit Energy
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Solution Overview
Problem
Wireless data communications face challenges in achieving high data rates while maintaining low power consumption and resisting interference, particularly at low signal-to-interference and noise ratios (SINR), where existing spread spectrum receivers struggle with synchronization and code acquisition due to hardware complexity and cost constraints.
Innovation Solution
The implementation of a receiver and reception method that uses the energy of multiple bits in a packet for correct alignment of the spreading code, enabling parallel search for code phases and tracking of timing and code phase, allowing for packet detection and acquisition at low SINR without external synchronization, utilizing a fully parallel VLSI architecture for improved reliability and range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If serial correlation approach is used for code acquisition, then hardware complexity is reduced, but acquisition time increases significantly
Solution Approach 1:
The patent divides the code acquisition process into two distinct phases: coarse acquisition using a reduced-complexity serial correlator to identify candidate code phases, and fine acquisition using a parallel correlator to precisely determine the correct code phase. This segmentation allows each stage to be optimized independently, reducing overall acquisition time while managing hardware complexity.
Solution Approach 2:
The patent performs preliminary coarse acquisition to identify candidate code phases before executing the computationally intensive parallel correlation for fine acquisition. This preliminary action reduces the search space for the parallel correlator, enabling faster and more accurate code phase determination without requiring full parallel processing from the start.
2Loss of time
If parallel correlators are used for code acquisition, then acquisition time is reduced, but hardware complexity and cost increase
Solution Approach 1:
The patent segments the correlator resources into two functional groups: a serial correlator for coarse acquisition that handles the initial broad search, and parallel correlators for fine acquisition that precisely determine the code phase. This segmentation enables the system to achieve fast acquisition without deploying full parallel correlators throughout the entire acquisition process.
Solution Approach 2:
The patent applies partial parallel processing only where most needed - during the fine acquisition stage for candidate code phases identified by the serial correlator. Rather than implementing excessive parallel processing for all possible code phases, the system uses parallel correlators selectively for the limited set of candidates, achieving sufficient acquisition speed with reduced hardware complexity.
3Measurement precision
If synchronous communication with pilot channel is used, then synchronization accuracy is improved, but power consumption increases
Solution Approach 1:
The patent extracts and removes the dedicated pilot channel from the asynchronous packet-based communication system. Instead, the system uses the data transmission itself for synchronization by processing multiple data bits to achieve code phase alignment and carrier recovery, eliminating the need for separate pilot signaling and reducing power consumption.
Solution Approach 2:
The patent makes the data transmission serve multiple functions simultaneously: it carries both the information payload and the synchronization function. By using the data bits themselves for code acquisition and carrier recovery through multi-bit processing, the system eliminates the need for dedicated pilot channels while maintaining synchronization capability.
4Use of energy by moving object
If data transmission power is reduced for low power operation, then power consumption decreases, but signal detection becomes more difficult at low SINR
Solution Approach 1:
The patent processes multiple consecutive data bits continuously to accumulate signal energy and improve detection reliability. By integrating information from multiple bits rather than relying on single-bit decisions, the system maintains robust signal detection capability even at low SINR conditions resulting from reduced transmission power.
Solution Approach 2:
The patent changes the detection parameter from single-bit decision to multi-bit integration. By combining and processing multiple data bits to determine code phase alignment and carrier frequency, the system effectively increases the signal-to-noise ratio through statistical accumulation, enabling reliable detection despite reduced transmission power.
Data Source
AI summary
Receivers and reception methods conduct spread spectrum reception using the energy of multiple bits, preferably a substantial number of bits, in a packet for correct alignment of the spreading code at the receiver. Code acquisition, as well as packet detection and acquisition are provided by embodiments of the invention. Preferred embodiment receivers and reception methods provide packet detection at low SINR looking at energy of multiple bits of the packet, frame synchronization using short preamble, timing recovery at low SINR looking at energy of multiple bits of the packet, quick code acquisition using parallel search for all possible code phases, code acquisition at low SINR, and tracking of acquired timing and code phase. Preferred embodiment receivers and reception methods use the energy of multiple bits for making decisions.