Naoki Kanada

92GHz 64QAM signal generation by optical frequency doubler

New communication system for high-speed train passengers is required to provide broadband services in the train. Radio over fiber in millimeter wave band is considered to provide a high throughput of the system. As a proof of concept, we generate 92 GHz 200 M symbol/sec 64QAM signals by optical frequency doubler. EVM of the signal is 7.14%. The result shows 1.2Gbps transmission is available in MMW band by radio over fiber.

Basic characteristic evaluation of aeromacs prototype system in send AI airport

A new aeronautical airport communication system called Aeronautical Mobile Airport Communications System (AeroMACS) is under standardizing. This paper reports performance evaluation of an AeroMACS prototype system on airport environment. First, we show that RSSI is the most important factor for airport condition. Second, we estimate coverage of the system. Finally, we compared the results of field test with those of laboratory test.

Evaluation of antenna configuration for aeronautical WiMAX at 5.1GHz

New high-speed aeronautical digital communication technologies will be required to cope with for increasing volumes of in air traffic. The Aeronautical Mobile Airport Communication System (AeroMACS) is a technology based on IEEE 802.16e which can use Multiple-Input Multiple-Output (MIMO) antenna systems to increase channel capacity. We experimentally evaluated the angle dependency of the MIMO effect around an aircraft in an airport environment by calculating the channel capacity around the aircraft using measurements from conventional Single-Input Single-Output (SISO), 2×2 MIMO, and 2×6 MIMO antenna systems. The 2×6 MIMO configuration gave the greatest channel capacity because of displacement of masking by the aircrafts empennage. It was thereby confirmed that an optimized MIMO antenna configuration provides greater channel capacity than conventional communication systems.

EVM and BER evaluation of C band new Airport surface communication systems

AeroMACS (Aeronautical Mobile Airport Communication System) is proposed for future airport surface communication system in the C band. In this paper, we report the results of an experiment at Sendai airport in Japan to evaluate the AeroMACS. Our base station covers the approximately 3km×1km rectangular airport surface with a transmitter power of 1W. A BER (Bit Error Rate) of less than 10-6 is required at the physical layer in order to realize reliable data communication systems. However, measurement of the BER is difficult especially in field experiments because another data link is required to inform the receiver of the correct transmitted symbols. Therefore, we calculate the relationship between EVM (Error Vector Magnitude) and BER by computer simulation, then translate the EVM which is measured in the experiment into BER. The results show that 64QAM-3/4 can be used with a BER of less than 10-6 in 64.3% of the LOS (Line Of Sights) area and 64QAM cannot be used in almost all NLOS (Non Line Of Sights) areas at Sendai airport.

Vector signal generation and transmission by radio over fiber system with frequency doubling at 96 GHz

The high-speed train in Japan connects megalopolises through many tunnels or underground routes. To provide seamless internet connectivity to the hundreds of passengers on the train, a new backhaul communication system is proposed in a millimeter-wave band by Radio over Fiber. We have shown that a vector-modulated signal can be generated by multiplying the radio frequency in the optical domain to avoid effects of chromatic dispersion in an optical fiber. In this paper, we show characteristics of long distance transmission by Radio over Fiber. Also, we present our concept and report on the relationship between the symbol rate and the modulation accuracy of the 96 GHz band signal generated by frequency doubling using RoF.

Onboard Antenna Placement Studies for CNPC Links of UAS Using AeroMACS

Recently, much attention has been paid to unmanned aircraft systems (UAS), especially for civilian purposes such as disaster prevention and transportation. This paper considers big long-flight-type UASs remotely piloted from ground station by radio communication link, since these types of UASs require higher reliability. The purpose of this paper is to consider a communication system which transmits real-time video of the surroundings of aircraft from unmanned aircraft to the ground pilot. In this paper, the aeronautical mobile airport communications system (AeroMACS) is considered as a command and non-payload communications (CNPC) link between unmanned aircraft and ground pilot. Flight tests using the experimental aircraft and AeroMACS prototype system are conducted to obtain the air-to-ground propagation profile. In addition, the placements of airborne antennas are considered, because the positional relationship between airborne antenna and ground fixed antenna is not constant during the flight. The results of flight tests show the effectiveness of our system, and the received signal strength indicator (RSSI) obtained by flight tests has the same tendency as the free space propagation model. Finally, the results of flight tests show that a vertical placement on top and bottom of aircraft body is effective for the multiple inputs and multiple outputs (MIMO) antenna configuration of UAS.

Vector signal generation by optical frequency doubler for MMW train communication systems

High-throughput communication technology based on the millimeter wave band have been developed to cope with an increase in communication demand in the future high-speed train. We are researching and developing to generate a vector signal in the millimeter wave band by multiplying the radio frequency in the optical domain. In this paper, we report on the relationship between the symbol rate and the modulation accuracy of the 96 GHz band signal generated by frequency doubling in the optical domain.

EVM evaluation for wideband radio over fiber system with frequency doubling at 96 GHz

Millimeter-wave (MMW) radio-over-fiber is a promising technology to provide wideband communication services for high-speed train passengers. Recently, we have proposed a novel signal generation scheme using frequency doubling, where baseband signals would be prepared by square root of desired I/Q-signals. In such systems, optical signals for wideband radio communication would be affected by chromatic dispersion of optical fibers because of its wide bandwidth. In this paper, we evaluate the relationship between symbol rate and EVM of long distance radio over fiber transmission.

An experimental evaluation on handover performance of AeroMACS prototype

AeroMACS (Aeronautical Mobile Airport Communications System) is an aeronautical wireless communication standard which provides high-speed fix/mobile network on the airport surface. AeroMACS is expected to gain the safety and efficiency of the airport operations by allowing the stakeholders such as air navigation service providers, airline companies, and airport authorities to exchange massive data traffic. The authors have been contributed to the standardization activities by providing the evaluation result of the developed prototype. In this context, this paper reports a Hand-Over (HO) test conducted in Sendai airport. HO is an important function that allows Mobile Stations (MSs) to change their connecting Base Stations (BSs) hence essential for covering a large airport which requires multiple BSs. As results of the test, performance metrics such as latency, Received Signal Strength Indicator (RSSI), Round Trip Time (RTT), and throughput are presented. The presented result will help the consideration of possible applications. In addition, the mitigation of RSSI fluctuation caused by multipath is discussed as a possible future improvement.

Experimental Evaluation on Quality of VoIP over Aero MACS

Aeronautical Mobile Airport Communications System (AeroMACS) is being standardized in order to provide new broadband wireless communications on airport surface. AeroMACS will be used for voice-based Air Traffic Control (ATC) services in the future as it is recommended in standards and recommended practices (SARPs) of the International Civil Aviation Organization (ICAO). Therefore, we evaluated the quality of voice over IP (VoIP) over AeroMACS for ATC. We developed the AeroMACS prototype system in Sendai Airport, a middle-size local airport in Japan. We carried out field experiments by using the prototype system to evaluate the quality of VoIP. In this paper, we provide experimental results and useful information for designing the AeroMACS system for VoIP-based ATC and airline operational control (AOC) services.