Ryoko Matsuo

20.4 A fully integrated single-chip 60GHz CMOS transceiver with scalable power consumption for proximity wireless communication

A fully-integrated single-chip CMOS transceiver with MAC and PHY for 60GHz proximity wireless communication is presented. A 60GHz wireless communication single-chip transceiver has not yet been reported due to large power consumption issues. However, by limiting the application to high-throughput proximity transmission, thermal issues arising in a single-chip have been overcome. A 2GHz broadband OFDM single-chip transceiver suffers from SNR degradation due to the reference clock (REFCLK) and baseband clock (BBCLK) spurs in RF/analog circuits. Low frequency spurs in the clock generator (CLKPLL) due to the mixing of the ADC/DAC sampling clock (SCLK) and other clocks such as REFCLK and BBCLK have been eliminated by careful frequency planning of those clocks. In addition to that, spur suppression in digital baseband and noise-tolerant RF/analog circuit designs are employed. The spurs have been successfully suppressed to less than -35dBc. The chip achieves a PHY data-rate of 2.35Gb/s and MAC throughput of 2.0Gb/s at a distance of 4cm. Power consumption is scalable to the throughput by the introduction of fast Sleep and Awake modes. The average power consumption at a throughput of 0.2Gb/s is reduced to 36% of that at 2.0Gb/s.

MAC Efficiency Enhancement with Prioritized Access Opportunity Exchange Protocol for 60 GHz Short-Range One-to-One Communications

This paper proposes a prioritized access opportunity exchange protocol for enhancing medium access control (MAC) efficiency in short-range one-to-one wireless communications on 60 GHz millimeter wave. A random back-off access protocol is widely spread for distributed wireless networks and is adopted in IEEE 802.11 WLAN standard. When many terminals try to access a wireless medium, the protocol works effectively in terms of fairness and throughput. However, when only two terminals try to access the wireless medium, its overhead becomes large and the MAC efficiency is degraded. In this paper, an access protocol that minimizes the access overhead is proposed for one-to-one communications. In the proposed protocol, a prioritized access opportunity (PAOP) is exchanged between two terminals. A terminal having the PAOP (primary terminal; PT) can access the medium with the minimum period whereas a terminal not having the PAOP (secondary terminal; ST) has to wait the transmission by the PT. If the PT has no data but the ST has data to be transmitted, the PT gives the PAOP to the ST. Then the ST becomes the new PT that accesses the medium with the minimum period. Total throughput and transmission delay performance by the back-off access protocol and by the proposed protocol is evaluated by the computer simulations and the results show the effectiveness of the proposed method.

MAC Efficiency Enhancement with ACK/NACK and AGC Pilot Signal Adaptation Mechanism in Millimeter-Wave Communication Systems

Millimeter-wave (mmWave) wireless systems are a focus of great interest for very high data transmission rate in a short range. Considering short-range communication with a range of the order of several tens of centimeters, only terminals present in this communication range will be influenced. In one-to-one communication, a simpler and more efficient access mechanism is required. Current CSMA/CA based MAC has limits to achieve a high data transmission by reasons of the low MAC efficiency, which is caused by a high overhead of signal exchanges, like interframe space (IFS) and acknowledgement. This paper proposes two methods that enhance the MAC efficiency in shortrange one-to-one communication. The ACK/NACK mechanism uses Negative ACK (NACK) as the acknowledgement policy and solves a problem arising from NACK. The automatic gain control (AGC) pilot signal adaptation mechanism adapts the length of the pilot signals for AGC.

Performance of simple and Smart PHY/MAC mechanisms for Body Area Networks

Measuring the living condition and health status of users using small sensing devices and collecting the data of each user over wireless networks is expected to be a new trend in healthcare. Body Area Network (BAN) is an emerging area of personal data communications that will facilitate the capture of data and its collection. Although the IEEE 802.15.6 standard for wireless body area networks was created for this purpose, it is very complex and is unsuitable for ultra low power sensors. A new BAN specification, under the Technical Committee (TC) on SmartBAN, is now being considered in the European Telecommunications Standards Institute (ETSI) targeting ultra low power devices. Some of the technical requirements of the new Smart BAN system includes ultra-low power consumption, coexistence with other wireless systems, a timely access mechanism and optimum control of quality of service (QoS) for emergency signals. A simple and energy efficient MAC/PHY system has been proposed by the authors as part of the ETSI TC Smart BAN specifications. In this paper, we introduce and evaluate our proposed Smart BAN system which is based on two channels, a control channel and a data channel. The control channel is used for announcements from which both nodes and neighboring hubs are able to gather information for use in co-existence algorithms as well as for initial connection setup. Our proposed system uses simple time division multiple access (TDMA) in the data channel so that the power consumption of nodes is kept low. A shared access mechanism has also been proposed to reduce the latency of emergency signals. We evaluate the access delay and power consumption of our system in this paper, and show that the proposed shared access mechanism reduces the latency of emergency signals.

An overview of ETSI TC SmartBAN MAC protocol

In this paper we introduce medium access control (MAC) protocol defined by ETSI TC (technical committee) SmartBAN (smart body area network). The key features of the protocol are a two-channel concept with different channels for data and control traffic, and a unique Multi-use Channel Access as one alternative channel access mode. The two-channel concept provides fast channel acquisition and easy Hub to Hub communications. Multi-use Channel Access guarantees for very-low latency emergency messaging for time-critical applications. In addition, Re-use Access mode of the Multi-use Channel Access enables the utilization of the scheduled but unused time slots thus increasing the channel utilization. The protocol is mainly a joint work between Centre for Wireless Communications (CWC) at the University of Oulu and Toshiba Research Europe Ltd.

Energy-efficient standby mode algorithm in short-range one-to-one millimeter wave communications

This paper proposes two energy-efficient standby mode algorithms in short-range one-to-one 60 GHz millimeter wave (mmWave) communications. Among the many usage scenarios for mmWave radio, file downloading from kiosk terminals or peer-to-peer sync service with portable terminals are of great interest. For these portable terminals, the power consumption of standby mode as well as connection setup time is important. Comparing the power consumption for a frame transmission with that for a frame reception in short-range one-to-one 60 GHz mmWave, the power consumption for a frame reception may become larger than that for a frame transmission. In this paper, two energy-efficient standby mode algorithms are proposed for one-to-one communications. In the proposed algorithms, each terminal operates based on Interval consisting of several Sub-intervals. One proposed algorithm (Prop1) is that a terminal transmits a connection request frame (CREQ) once at every Sub-interval and the other terminal waits for the CREQ during one Sub-interval per each Interval. Thus, Prop1 saves the power consumption for a CREQ transmission. The other proposed algorithm (Prop2) is that a terminal selects one Sub-interval randomly for each Interval and transmits CREQs repeatedly during that Sub-interval. The other terminal waits for a CREQ during this CREQ transmission period at every Sub-interval. Prop2 saves the power consumption for a CREQ reception. We evaluate the power consumption of standby mode and connection setup time for Prop1 and Prop2 by both numerical analysis and computer simulations. We compare these proposed algorithms under several ratio of the power consumption for transmission and reception.