Efficient Storage Method for Real-Time Simulation of Wide-Range Multipath Delay Spread Channels

LI Weishi; ZHOU Hui; JIAO Xun; XU Qiang; TANG Youxi

doi:10.11999/JEIT250525

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LI Weishi, ZHOU Hui, JIAO Xun, XU Qiang, TANG Youxi. Efficient Storage Method for Real-Time Simulation of Wide-Range Multipath Delay Spread Channels[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT250525

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LI Weishi, ZHOU Hui, JIAO Xun, XU Qiang, TANG Youxi. Efficient Storage Method for Real-Time Simulation of Wide-Range Multipath Delay Spread Channels[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT250525

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Efficient Storage Method for Real-Time Simulation of Wide-Range Multipath Delay Spread Channels

doi: 10.11999/JEIT250525 cstr: 32379.14.JEIT250525

LI Weishi¹,
ZHOU Hui^{1, 2
,
,},
JIAO Xun²,
XU Qiang¹,
TANG Youxi¹

1.
National Key Laboratory of Wireless Communications, University of Electronic Science and Technology of China, Chengdu 611731, China
2.
Laboratory of Electromagnetic Space Cognition and Intelligent Control, Beijing 100089, China

Funds: The National Key Research and Development Program of China (2023YFF0717700)

Received Date: 2025-06-09
Rev Recd Date: 2025-09-04

Available Online: 2025-09-21

Abstract

Abstract

Objective The real-time channel emulator is a critical tool in wireless device research and development, enabling accurate and repeatable experiments in controlled laboratory environments. This capability reduces testing costs by avoiding extensive field trials and accelerates development cycles by allowing rapid iteration and validation of wireless devices under realistic conditions. With the rapid advancement of aerial platforms—including drones, High-Altitude Pseudo-Satellites (HAPS), and Unmanned Aerial Vehicles (UAVs)—for integrated sensing and communication, high-resolution imaging, and environmental reconstruction in complex wireless environments, the challenges of channel modeling have increased considerably. In particular, there is growing demand for real-time simulation of wide-range multipath delay spread channels. Existing simulation methods, although effective in traditional scenarios, face substantial limitations in hardware storage resources when handling such channels. This study addresses these limitations by proposing an efficient storage method for real-time emulation of wide-range multipath channels. The method reduces memory overhead while preserving high fidelity in channel reproduction, thereby offering a practical and optimized solution for next-generation wireless communication research. Methods In conventional real-time channel emulation, a combined simulation approach is adopted, employing cascaded common delay and multipath delay spread components. The common delay component is implemented using a single high-capacity memory module, whereas the multipath delay spread component is implemented using a Dense Tapped Delay Line (D-TDL). This design reduces storage resource requirements by multiplexing the common delay component, but the achievable multipath delay spread range remains limited. Moreover, the multipath delay is constrained by the common delay component, reducing flexibility and compromising the ability to emulate complex scenarios. The Sparse Tapped Delay Line (S-TDL) scheme is used in some algorithms to extend the multipath delay emulation range by cascading block memory modules. However, this method introduces inter-tap delay dependencies and cannot adapt to the requirements of wide-range multipath delay spread channels. Alternatively, Time-Division Multiplexing (TDM) is applied in other algorithms to improve the utilization efficiency of block memory modules and decouple multipath delay control. Despite this, TDM is constrained by the read/write bandwidth of memory, making it unsuitable for real-time channel emulation of large-bandwidth signals. To overcome the multi-tap delay coupling issue in the S-TDL algorithm, an Optimized Sparse Tapped Delay Line (OS-TDL) algorithm is proposed. By analyzing delay-dependent relationships among multipath taps, theoretical derivation establishes an analytical relationship between the number of multipaths and the delay spread range achievable under decoupling constraints. Redundant taps are introduced to eliminate inter-tap delay dependencies, enabling flexible configuration of arbitrary multipath delay combinations. The algorithm formulates a joint optimization model that balances hardware memory allocation and multipath delay spread fidelity, supports wide-range multipath scenarios without being limited by memory read/write bandwidth, and allows real-time emulation of large-bandwidth signals. The central innovation lies in dynamically constraining tap activation and sparsity patterns to reduce redundant memory while preserving wide-range multipath delay spread channel characteristics. Compared with conventional approaches, the proposed algorithm significantly enhances storage resource utilization efficiency in wide-range multipath channel emulation. On this basis, a concrete algorithmic procedure is developed, in which an input multipath delay sequence is computationally processed to derive delay configuration parameters and activation sequences for multiple cascaded memory units. Comprehensive validation procedures for the algorithm are presented in later sections. Results and Discussions Conventional S-TDL algorithms are constrained by inter-tap delay coupling, which limits their ability to achieve high-fidelity emulation of wide-range multipath delay variations. To overcome this limitation, a comparative simulation of three algorithms—the memory resource exclusive algorithm, the TDM memory resource algorithm, and the OS-TDL algorithm proposed herein—is systematically conducted. A controlled variable approach is employed to evaluate storage resource utilization efficiency across three key dimensions: signal sampling rate, number of emulated multipath components, and multipath delay spread range. Theoretical analysis and simulation results show that the proposed OS-TDL algorithm significantly reduces memory requirements compared with conventional methods, while maintaining emulation fidelity. Its effectiveness is further verified through experimental implementation on AMD’s Virtex UltraScale+ series high-performance Field-Programmable Gate Array (FPGA), using the XCVU13P verification platform. Comparative FPGA resource measurements under identical system specifications confirm the superiority of the proposed algorithm, demonstrating its ability to improve memory efficiency while accurately reproducing wide-range multipath delay spread channels. Conclusions This study addresses the challenge of storage resource utilization efficiency in real-time channel emulation for wide-range multipath delay spread by analyzing the inter-tap delay dependency inherent in conventional S-TDL algorithms. An OS-TDL algorithm is proposed to emulate wide-range multipath delay spread channels. Both simulation and hardware verification results demonstrate that the proposed algorithm substantially improves storage efficiency while accurately reproducing multipath wide-range delay spread characteristics. These findings confirm that the algorithm meets the design requirements of real-time channel emulators for increasingly complex verification scenarios.
- Real-time channel emulation,
- Multipath delay spread,
- Tapped delay line,
- Hardware memory resources

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References(18)

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