Seungwon Choi

ETSI reconfigurable radio system — Standard architecture and radio application

This paper introduces the ETSI-standard architecture for a reconfigurable Mobile Device (MD) of which the configuration is determined by the downloaded radio application. First, this paper introduces key components of the standard architecture. Then, this paper shows how the radio application codes can be distributed from a public domain to target MDs. In the distribution of radio application codes, this paper considered 3 different cases, i.e., when the radio application codes are given in a form of executable code, source code, or intermediate representation, while both static and dynamic linking of functional blocks are also taken into considerations.

Implementation of a Non-Codebook Based MU-MIMO System for TDD LTE-Advanced

This paper presents a non-codebook based Multiple User Multiple Input Multiple Output (MU-MIMO) test-bed system for Time Division Duplexing (TDD) Long Term Evolution-Advanced (LTE-A), which has been implemented for verifying the performance of a dynamic precoding procedure. Using the parameter of propagation path gain, the proposed MU-MIMO system can adaptively switch the precoder to guarantee that the upper bound BER is maintained with a minimum computational burden.

Adaptive automotive communications solutions of 10 years lifetime enabled by ETSI RRS software reconfiguration technology

The vehicles typically have a lifetime of several years, possibly even longer than 10 years, over which communication technology will almost certainly evolve dramatically. The challenge of automotive communication platform is to ensure that a radio communication component remains relevant over the entire lifetime of a vehicle. A highly efficient software reconfiguration solution is introduced in this paper. ETSI Reconfiguration Radio System technology provides a suitable framework for automotive communication platform which allows to either add or replace entire Radio Access Technologies or to upgrade specific components across any of the entire layers.

Highly efficient representation of reconfigurable code based on a radio virtual machine: Optimization to any target platform

ETSI has developed a novel Software Radio Reconfiguration framework encompassing technical, certification and security solutions. Compared to legacy Software Reconfiguration technology, such as the Software Communications Architecture, the ETSI solution is designed for lowest overall power consumption and efficiency. For this purpose, a novel approach for Code Portability has been developed — a Radio Virtual Machine based mechanism allows converting a given algorithm into a generic representation, which is then, optimized for the specific hardware resources available on a target platform. This contribution explains the basic principles and outlines how Code Portability is achieved while meeting the objectives in terms of power consumption and complexity.

Novel Beamforming and User Scheduling Algorithm for Inter Cell Interference Cancellation

Coordinated multi-point transmission is a candidate technique for next-generation cellular communications systems. We consider a system with multiple cells in which base stations coordinate with each other by sharing user channel state information, which mitigates inter-cell interference (ICI), especially for users located at the cell edge. We introduce a new user scheduling method that considers both ICI and intra-cell orthogonality. Due to the influence of ICI cancellation and the loss reduction of effective channel gain during the beamforming process, the proposed method improves the system sum rate, when compared to the conventional method, by an average of 0.55bps/Hz for different numbers of total users per cell.

Implementation of reconfigurable mobile device with licensed shared access functionality

Recently, as the heterogeneous network (HetNet) has been deployed widely to support various kinds of Radio Access Networks(RANs) with a combination of Macro, Pico, and/or Femto cells, research and standardization regarding the concept of Licensed Shared Access (LSA) for supporting spectrum sharing have been very actively performed. Especially, Working Group 1 (WG1) of Technical Committee (TC) Reconfigurable Radio System (RRS) of European Telecommunications Standards Institute (ETSI) has been a main driving force for developing a system requirements and use cases for the LSA system, while WG2 has set up a standard architecture of reconfigurable Mobile Device (MD) that can be applied to the LSA system. In this paper, we introduce the reconfigurable MD architecture for supporting LSA-based spectrum sharing. An implementation of a test-bed of reconfigurable MD is presented in order to verify the feasibility of the standard MD architecture for the purpose of LSA-based spectrum sharing through various experimental tests.

Operation of reconfigurable mobile device for spectrum sharing

In order for a mobile device to efficiently support the spectrum sharing, the mobile device shall be reconfigurable, meaning that its radio application code has to be adaptively changed in accordance with the hopping of desired spectral band. Based on the standard architecture defined in Working Group (WG)2 of Technical Committee (TC) - Reconfigurable Radio System (RRS) of European Telecommunications Standards Institute (ETSI), this paper presents related procedures among the software entities of the reconfigurable mobile device required for implementing the spectrum sharing. In this paper, we consider the scenario of the spectrum sharing that has been demonstrated in WG1 of TC-RRS of ETSI. The related parameters such as center frequency, modulation scheme, etc considered in this paper are also based on what have been presented by the WG1 of TC-RRS. This paper also addresses the interactions among the standard software entities of the reconfigurable mobile device and required interfaces services.

Performance analysis of a MU-MIMO system with limited feedback and user selection

This paper proposes a novel user selection algorithm to enhance the system performance of a multi-user, multiple-input, multiple-output (MU-MIMO) system. The proposed algorithm first selects a primary user set using a predetermined threshold, and selects sub-users for each primary user to define user groups that maximize the determinant of the channel matrix consisting of selected user(s) and a candidate user. The user group that provides the maximum sum rate is then determined. According to computer simulation results, the proposed algorithm improves the system sum rate, compared to the conventional algorithm, by approximately 0.5bps/Hz.

Calibration method using the Zadoff-Chu sequence

A novel calibration method using the Zadoff-Chu (ZC) sequence as a test signal is proposed. Using this technique, the timing information of the received test signal that contains the phase characteristics of each antenna path can be accurately estimated. Performance of the proposed method is first analyzed through computer simulation. Then, the proposed calibration algorithm is implemented on a Field Programmable Gate Array (FPGA) board to verify its excellent performance in terms of the estimation accuracy for both the amplitude characteristics and the phase characteristics of each antenna path of a given array system.