To meet the future demand for huge traffic volume of wireless data service, the research on the fifth generation
(5G) mobile communication systems has been undertaken in recent years. It is expected that the spectral and energy
efficiencies in 5G mobile communication systems should be ten-fold higher than the ones in the fourth generation
(4G) mobile communication systems. Therefore, it is important to further exploit the potential of spatial multiplexing
of multiple antennas. In the last twenty years, multiple-input multiple-output (MIMO) antenna techniques have been
considered as the key techniques to increase the capacity of wireless communication systems. When a large-scale
antenna array (which is also called massive MIMO) is equipped in a base-station, or a large number of distributed
antennas (which is also called large-scale distributed MIMO) are deployed, the spectral and energy efficiencies can
be further improved by using spatial domain multiple access. This paper provides an overview of massive MIMO
and large-scale distributed MIMO systems, including spectral efficiency analysis, channel state information (CSI)
acquisition, wireless transmission technology, and resource allocation.
Due to the asymmetry between the amount of data traffic in the downlink and
uplink direction of nowadays and future wireless networks, a proper design of the
transceivers in the broadcast channel is inevitable in order to satisfy the users’
demands on data rate and transmission quality. This book deals with the optimi-
zation-based joint design of the transmit and receive filters in a MIMO broadcast
channel in which the user terminals may be equipped with several antenna ele-
ments.
Digital mobile wireless communication and the Internet have undergone a
fantastic growth in the last few years and, despite originating from two different
worlds, they are converging. This convergence corresponds to the evolution of
mobile systems towards the highest broadband data transmissions (GSM,
EDGE/GPRS, UMTS then HSDPA), while the computing world gets equipped with
wireless technologies such as Wi-Fi or Wi-Max.
A mobile ad-hoc network (MANET) is formed by multiple moving nodes
equipped with wireless transceivers. The mobile nodes communicate with
each other through multi-hop wireless links, where every node can transmit
and receive information. Mobile ad-hoc networks have become increasingly
important in areas where deployment of communications infrastructure is
difficult.
Thanks to the advances in micromachining fabrication technologies and significant
cost reduction due to mass production, miniature sensors of angular rate, or
gyroscopes, found their way into the everyday life of every user of modern gadgets,
such as smart phones, tablets or even wristwatches. Often without realising, many
of us are carrying in our pockets fully equipped with all necessary sensors complete
inertial navigation systems that not so long ago were available only for advanced
vehicles in sea, land, air or space. Accelerometers and gyroscopes are found in
specifications of any gadget supposed to react to user movements. And one of the
most commonly used type of gyroscopes used to developed these systems is
Coriolis vibratory gyroscope (CVG).
The term “ smart grid ” defi nes a self - healing network equipped with dynamic optimiza-
tion techniques that use real - time measurements to minimize network losses, maintain
voltage levels, increase reliability, and improve asset management. The operational data
collected by the smart grid and its sub - systems will allow system operators to rapidly
identify the best strategy to secure against attacks, vulnerability, and so on, caused by
various contingencies. However, the smart grid fi rst depends upon identifying and
researching key performance measures, designing and testing appropriate tools, and
developing the proper education curriculum to equip current and future personnel with
the knowledge and skills for deployment of this highly advanced system.
鋰電池BMS管理技術(shù)是移動(dòng)機(jī)器人的關(guān)鍵技術(shù),本文設(shè)計(jì)了基于bq76PL455、STM32F103的鋰電池管理系統(tǒng),實(shí)現(xiàn)了電池組電壓、電流、過(guò)壓、過(guò)流等狀態(tài)監(jiān)測(cè);系統(tǒng)配置均衡電路,電池充電過(guò)程中若出現(xiàn)電池單體電壓不平衡現(xiàn)象,會(huì)觸發(fā)均衡電路,進(jìn)而提高電池的安全性,延長(zhǎng)使用壽命。Lithium battery BMS management technology is the key technology of mobile robot.The lithium battery management system based on bq76PL455 and STM32F103 is proposed to realize the monitoring of battery pack voltage,current,overvoltage and overcurrent.The system is equipped with equalization circuit.When the battery cell voltage imbalance occurs,the equalization circuit is triggered to improve the safety and service life of the battery.
本文首次設(shè)計(jì)并驗(yàn)證了基于macom三合一芯片設(shè)計(jì)的光模塊電路,該電路旨在提供一種滿足SFF-8472中規(guī)定的數(shù)字診斷功能的低成本SFP+模塊。電路采用激光器驅(qū)動(dòng)、限幅放大器、控制器以及時(shí)鐘恢復(fù)單元集成的單芯片,在保證高精度數(shù)字診斷功能基礎(chǔ)上,實(shí)現(xiàn)了低成本高可靠的特點(diǎn)。該電路在光接收接口組件與激光器驅(qū)動(dòng)和限幅放大器單元的限幅放大器部分之間接入濾波器來(lái)提高模塊的靈敏度及信號(hào)質(zhì)量。在控制器單元的數(shù)字電位器的引腳上采用外加電阻的方式避免出現(xiàn)上電不發(fā)光的故障問(wèn)題。該研究結(jié)果為下一代SFP-DD光模塊設(shè)計(jì)與開(kāi)發(fā)工作,奠定了一定的理論與實(shí)踐基礎(chǔ)。This paper designs and validates the optical module circuit based on the MACOM Trinity chip for the first time.This circuit aims to provide a low-cost SFP module which meets the digital diagnosis function specified in SFF-8472.The circuit uses a single chip integrated with laser driver,limiting amplifier,controller and clock recovery unit.On the basis of ensuring high precision digital diagnosis function,it achieves the characteristics of low cost and high reliability.The circuit connects a filter between the optical receiving interface module and the limiting amplifier part of the laser driver and limiting amplifier unit to improve the sensitivity and signal quality of the module.The pin of the digital potentiometer in the controller unit is equipped with an external resistance to avoid the problem of power failure.The research results lay a theoretical and practical foundation for optical module design in high-speed data center.
