터보 부호의 오류 마루 현상 개선을 위한 방법

안흥섭(Heung-Seop Ahn),김성래(Sung-Rae Kim),김현경(Hyun-Kyung Kim),신동준(Dong-Jun Shin) 한국통신학회 2012 한국통신학회 학술대회논문집 Vol.2012 No.11

주파수 선택적 신호 환경에서 안테나 어레이의 FBMC/OQAM 시스템 적용

김예카테리나,안흥섭,최승원 (사)디지털산업정보학회 2019 디지털산업정보학회논문지 Vol.15 No.1

Despite attractive advantages such as good time-frequency localization and improved spectral efficiency, filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) suffers from multipath fading. In highly frequency-selective channels, the effect of multipath interference can significantly distort the FBMC/OQAM signal due to the absence of cyclic prefix. To resolve the problem of the multipath interference in FBMC/OQAM, this paper proposes applying an antenna array that provides well shaped beam pattern for each multipath. To evaluate the performance of the proposed array system, various computer simulations have been conducted. The accuracy of direction of arrival estimation is demonstrated through spatial spectrum for a different number of antennas in a sub-array. The performance improvement is presented in terms of bit error rate. We found that the proposed array system mitigate the multipath interferences in Extended Typical Urban model with 12 antennas in a sub-array. Moreover, as the number of antennas in a sub-array increases, the system provides a signal-to-noise ratio gain.

5G 이동통신 셀 설계를 위한 타부 탐색과 유전 알고리즘의 성능

권오현,안흥섭,최승원,Kwon, Ohyun,Ahn, Heungseop,Choi, Seungwon 디지털산업정보학회 2017 디지털산업정보학회논문지 Vol.13 No.3

The fifth generation(5G) of wireless networks will connect not only smart phone but also unimaginable things. Therefore, 5G cellular network is facing the soaring traffic demand of numerous user devices. To solve this problem, a huge amount of 5G base stations will need to be installed. The base station positioning problem is an NP-hard problem that does not know how long it will take to solve the problem. Because, it can not find an answer other than to check the number of all cases. In this paper, to solve the NP hard problem, we compare the tabu search and the genetic algorithm using real maps for optimal cell planning. We also perform Monte Carlo simulations to study the performance of the Tabu search and Genetic algorithm for 5G cell planning. As a results, Tabu search required 2.95 times less computation time than Genetic algorithm and showed accuracy difference of 2dBm.

범용 DSP를 이용한 RRS 기반 기지국 통신 플랫폼 구현

김호일,안흥섭,최승원 (사)디지털산업정보학회 2018 디지털산업정보학회논문지 Vol.14 No.4

One of the problems with the base station equipment is that there is a large difference between the replacement time of the hardware equipment such as the base station equipment and the radio access equipment, and the evolution period of the communication standard. Therefore, the base station communication platform must be flexible enough to handle the evolving communication standards after purchase. Recent research on reconfigurable communications platforms has focused on the efficient architecture of the communications platform to meet these requirements through software downloads while still using existing hardware. This paper presents a prototype of a base station communications platform based on the ETSI standard reconfigurable architecture. The communication platform presented in this paper is implemented as an ETSI standard reconfigurable architecture using a general-purpose DSP (Digital Signal Processor). In the implemented prototype, we verify the real-time feasibility of communication protocol updates through software reconfiguration

CNN 기반의 IEEE 802.11 WLAN 프레임 포맷 검출

김민재,안흥섭,최승원 (사)디지털산업정보학회 2020 디지털산업정보학회논문지 Vol.16 No.2

Backward compatibility is one of the key issues for radio equipment supporting IEEE 802.11, the typical wireless local area networks (WLANs) communication protocol. For a successful packet decoding with the backward compatibility, the frame format detection is a core precondition. This paper presents a novel frame format detection method based on a deep learning procedure for WLANs affiliated with IEEE 802.11. Considering that the detection performance of conventional methods is degraded mainly due to the poor performances in the symbol synchronization and/or channel estimation in low signal-to-noise-ratio environments, we propose a novel detection method based on convolutional neural network (CNN) that replaces the entire conventional detection procedures. The proposed deep learning network provides a robust detection directly from the receive data. Through extensive computer simulations performed in the multipath fading channel environments (modeled by Project IEEE 802.11 Task Group ac), the proposed method exhibits superb improvement in the frame format detection compared to the conventional method.

멀티코어 DSP를 이용한 다중 안테나를 지원하는 SDR 기반 LTE-A PDSCH 디코더 구현

나용,안흥섭,최승원 (사)디지털산업정보학회 2019 디지털산업정보학회논문지 Vol.15 No.4

This paper presents a SDR-based Long Term Evolution Advanced (LTE-A) Physical Downlink Shared Channel (PDSCH) decoder using a multicore Digital Signal Processor (DSP). For decoder implementation, multicore DSP TMS320C6670 is used, which provides various hardware accelerators such as turbo decoder, fast Fourier transformer and Bit Rate Coprocessors. The TMS320C6670 is a DSP specialized in implementing base station platforms and is not an optimized platform for implementing mobile terminal platform. Accordingly, in this paper, the hardware accelerator was changed to the terminal implementation to implement the LTE-A PDSCH decoder supporting the multi-antenna and the functions not provided by the hardware accelerator were implemented through core programming. Also pipeline using multicore was implemented to meet the transmission time interval. To confirm the feasibility of the proposed implementation, we verified the real-time decoding capability of the PDSCH decoder implemented using the LTE-A Reference Measurement Channel (RMC) waveform about transmission mode 2 and 3.

TMS320C6670 기반 LTE-A PDSCH 디코더 구현

이광민,안흥섭,최승원 (사)디지털산업정보학회 2018 디지털산업정보학회논문지 Vol.14 No.4

This paper presents an implementation method of Long Term Evolution-Advanced (LTE-A) Physical Downlink Shared Channel (PDSCH) decoder using a general-purpose multicore Digital Signal Processor (DSP), TMS320C6670. Although the DSP provides some useful coprocessors such as turbo decoder, fast Fourier transformer, Viterbi Coprocessor, Bit Rate Coprocessor etc., it is specific to the base station platform implementation not the mobile terminal platform implementation. This paper shows an implementation method of the LTE-A PDSCH decoder using programmable DSP cores as well as the coprocessors of Fast Fourier Transformer and turbo decoder. First, it uses the coprocessor supported by the TMS320C6670, which can be used for PDSCH implementation. Second, we propose a core programming method using DSP optimization method for block diagram of PDSCH that can not use coprocessor. Through the implementation, we have verified a real-time decoding feasibility for the LTE-A downlink physical channel using test vectors which have been generated from LTE-A Reference Measurement Channel (RMC) Waveform R.6.

Design and Implementation of Software Defined Radio Based IEEE 802.11ac Encoder Using Multicore DSP

장중봉,안흥섭,최승원 (사)디지털산업정보학회 2019 디지털산업정보학회논문지 Vol.15 No.4

This paper presents a software design and implementation of software-defined radio based IEEE 802.11ac encoder using Texas Instruments TMS320C6670 digital signal processor (DSP) platform. In this paper, the implemented encoder has the capability of generating all the signals consisting of preamble field and data field under different modulation & coding scheme in the IEEE 802.11ac standard. Moreover, the flexibility in choosing different rate, bandwidth, or mode can also be achieved by software reconfiguration using the DSP. As a result, by utilizing the computing power provided by multi-cores as well as the FFT coprocessors in the DSP, the required maximum throughput 78Mbps can be fully reached within 4 μs for each OFDM symbol in the case of 20MHz bandwidth of IEEE 802.11ac.

TI C66x DSP를 위한 적응형 PCIe 시스템

김민재,진화종,안흥섭,최승원 (사)디지털산업정보학회 2019 디지털산업정보학회논문지 Vol.15 No.4

This paper proposes an adaptive PCIe system for TI C66x DSPs. Conventionally, the PCIe system provided by the C66x is a system dependent on the structure in which the primary core writes an application to the DSP memory through the PCIe interface, then activate the secondary core. Due to the dependency between the cores, when developing a project using a PCIe interface, the remaining cores have to be programmed with a concern of the primary core used as the PCIe interface. Therefore, in order to de-couple the connections among the cores, an adaptive PCIe system is proposed, in the paper, in which the cores operate independently compared to the conventional system. Since the core used as the PCIe interface only runs PCIe related operations in the new system, the remaining cores can be fully utilized without concerning the connections with the core for PCIe interface. In order to verify the feasibility of the proposed adaptive PCIe system, the implementations of LTE-A down link, and IEEE 802.11ac are carried out using the evaluation board which includes a TMS320C6670 chip. Altogether, these results support that we demonstrated that the digital signal processing systems with the PCIe Interface can be developed more rapidly by applying the proposed system.