Yukimasa Nagai

324Mbps WLAN equipment with MAC frame aggregation

We developed a high speed wireless LAN prototype in the 5 GHz band. Maximum transmission rate of the developed WLAN equipment was 324 Mbit/sec using 6 multi-channels of 802.11a. We proposed a novel frame aggregation scheme to improve MAC efficiency. The proposed frame aggregation scheme had a feature of an adaptive aggregation size selection depending on wireless channel conditions and application requirements. Throughput performance was simulated in the case of multiple stations with the proposed frame aggregation. The evaluated system throughput was achieved more than 150 Mbit/sec in the case of 10 STAs. It is found that throughput of the developed equipment was measured to be more than 170 Mbit/sec using the proposed frame aggregation

Location Based Data Delivery Schedulers for Vehicle Telematics Applications

This paper proposes four schedulers using location information and side information in telematics applications for vehicular networks. The scheduler algorithms consider peak traffic and link reliability, achieving savings of channel resources and reducing the number of retransmissions. A key feature of the proposed schedulers is the use side information in the form of a coverage map, which provides a map of link quality for the area covered by the radio access networks. In this paper, the total offered load and average excess delay are considered as two metrics for measuring the proposed schedulers, which are evaluated by simulation results. The performance of schedulers is reported and compared.

324Mbps WLAN Equipment with MAC Frame Aggregation for High MAC-SAP Throughput

We developed a high speed wireless LAN prototype in the 5GHz band. Maximum transmission rate of the developed WLAN equipment was 324Mbit/sec using 6 multi-channels of 802.11a. We proposed a novel frame aggregation scheme to improve MAC efficiency. The proposed frame aggregation scheme had a feature of an adaptive aggregation size selection depending on thewireless channel conditions and application requirements. Throughput performance was obtained from simulation using a multiple station system with the proposed frame aggregation. A throughput of more than 150Mbit/sec was achieved with an evaluated system of 10 STAs. We also found that the measured throughput of more than 170Mbit/sec was achieved using the proposed frame aggregation.

A SINR estimation for closed-loop link adaptation of 324 Mbit/sec WLAN system

We developed a high speed wireless LAN prototype in 5 GHz frequency band. Maximum transmission rate of the developed WLAN system is 324 Mbit/sec using 6 multi-channels of the IEEE802.11a. We propose a SINR estimation scheme using the correlation of long training fields, and implemented it in closed-loop link adaptation. We compared the proposed link adaptation schemes with the legacy ACK-based link adaptation schemes by computerized simulation. It was found that the performances of legacy ACK-based link adaptation schemes depended largely on the parameter choices. The proposed link adaptation scheme achieved higher throughput than the legacy ACK-based link adaptation schemes. We also found that the proposed link adaptation scheme selected the optimal MCS on the developed WLAN system in both AWGN and fading conditions.

Improvement of bit error rate using channel interleaving for channel binding WLAN prototype

High speed wireless LAN prototype of 324 Mbit/sec has been developed. Six channel binding of 802.11 a signal on frequency domain was employed for increasing PHY data rate. Frame aggregation was employed to improve MAC-SAP throughput. Individual adaptive data rate setting on each channel, so called adaptive dynamic channel assign was implemented in order to achieve maximum MAC-SAP throughput at any channel condition. In this paper, multiple channel interleaving over all frequency channels for randomization of burst error was presented. Interleaving can be carried out over all channels or inside individual channel. Bit and packet error rate were measured using implemented WLAN equipements with/without multiple channel interleaving. It was confirmed that improvement using multiple channel interleaving were measured to be 2 dB.

A Closed-Loop Link Adaptation Scheme for 324Mbit/sec WLAN System

We developed a high speed wireless LAN prototype in the 5 GHz band. Maximum transmission rate of the developed WLAN system is 324 Mbit/sec using 6 multi-channels of 802.11a. We propose a closed-loop link adaptation scheme to improve MAC efficiency. The proposed scheme inserts MCS (Modulation and Coding Scheme) feedback information into Data frame and ACK frame. The MCS is calculated based on the estimated SNR. We compared the proposed link adaptation scheme with the legacy ACK-based link adaptation schemes by computerized simulation. The proposed link adaptation scheme achieved higher throughput than the legacy ACK-based link adaptation scheme. We also found that the proposed link adaptation scheme selected the optimal MCS on the developed WLAN system.

Demonstration of HDTV Transmission Using 324Mbps WLAN Equipment

We developed a high speed wireless LAN prototype in the 5GHz band. Maximum transmission rate of the developed WLAN equipment was 324Mbit/sec using 6 multi-channels of 802.11a (1). We implemented a frame aggregation scheme to improve MAC efficiency (2-3). The evaluated system throughput was achieved more than 170Mbit/sec using the implemented frame aggregation. The HDTV transmission using 324Mbit/sec WLAN equipment was demonstrated. We compared the developed prototype and the conventional 802.11g (4).