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The detailed difference between 4G industrial router...   4G industrial router and 4G DTU both realize the wireless network data transmission function, and the differences between them are mainly from the use method, appearance interface and application environment, etc. Today, we will introduce some differences between 4G router and 4G DTU.   Different methods...

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Application analysis of iot sensing technology   The Internet of things (iot) is widely used in the integration of networks through intelligent perception, recognition technology, pervasive computing and other communication perception technologies. The iot is understood as "Internet connected by things". The Internet of things (iot) connects all objects with...

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What is a single/dual frequency wireless 4G router 1. Introduction to "single frequency" router The single-frequency router only works in the 2.4ghz band, which is generally supported by wireless terminals. However, the 2.4ghz band has large interference, which may affect the wireless rate and stability.   2. Introduction to "dual-frequency" router Dual-frequency...

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Wireless communication DTU features Data Transfer unit (DTU) is a wireless terminal device specially used to convert serial Data into IP Data or convert IP Data into serial Data for transmission through wireless communication network.   DTU advantages: Rapid and flexible network, short construction cycle, low cost; Wide network coverage; Good...

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The advantage of using wireless data transmission module... Data transmission can be simply divided into two major types: wired (including the installation of optical cables, cables or leased telecommunication lines) and wireless (including the establishment of dedicated wireless data transmission system or the borrowing of CDPD, GSM, CDMA and other public network information platforms).     In...

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Nokia #India announces #5G #IoT for #SmartCities

Category : 其他, 技术相关

The Finnish company showcased more than 60 different use-cases of these technologies at its annual Innovation Day in Bengaluru, including those that are already live and ready for use as well as ones that aren’t live yet.

Nokia’s research and development office in Bengaluru, which has around 5,000 employees, creates solutions for both its Indian and international markets. Its new IoT range, though, will focus more on Indian clients, especially governments.

“5G and IoT are going to be the future trends that we see in the marketplace. While from an India standpoint it’s still an early stage for 5G to happen, IoT is taking a bit of a step forward in terms of adoption here,” Randeep Raina, chief technology officer for Nokia India said in an interview on Wednesday.

“There are certain initiatives led by the government right now in the form of digital India and smart city programs. IoT could be one of the enablers to make cities a bit safer and smarter. It’s with that intent that we’d put a theme out here on this innovation day,” he said.

The three main solutions, or use-cases, showcased by the company on Wednesday were video analytics of real-time city surveillance, a public safety service that can be deployed at railroad crossings and a smart parking service.

Based on real-time city surveillance via cameras deployed at various public locations Nokia’s IoT solution will be able to provide clients – mostly governments and policing authorities – with data analysis. The analysis includes everything from identifying anomalies, such as incorrect pedestrian crossings, to tracking traffic patterns.

Its public safety solution uses sensors, beacons and cameras and is aimed at keeping pedestrians from straying across the path of oncoming trains at railroad crossings. This service will both warn people crossing railroads on foot of an oncoming train as well as alert the authorities and issue notice of a fine in case people cross even after receiving a warning. The warning messages will appear on any device using any service provider and are not app-based, i.e. the user will not need to install an app to see the messages.

Nokia’s smart parking solution will target organized parking lots that can use it to fully automate the process – from identifying a car on entry and guiding the driver to free parking spots through an app, to recording the number of hours a car is parked at the lot and bill payment online via the app.

Roughly two months ago, auto components supplier Bosch Ltd also launched solutions targeted at creating smart cities, including a smart parking service that will help commuters find space in crowded areas. The German company has other similar solutions that are, again, aimed at assisting traffic policing and citizen safety and security systems.

M2M Magazine  http://www.machinetomachinemagazine.com/2016/12/15/nokia-india-announces-5g-iot-for-smartcities/

Research: China IoT Market is expected to Worth 121.45 Billion USD by 2022

Category : 其他, 技术相关

According to the new market research report China IoT Market by Hardware (Processor, Memory, Logic, Sensor, & Connectivity), Software (Real-Time Streaming, Network Security, Data Management, Remote Monitoring, & Bandwidth Management), Platform, Service, and Application – Global Forecast to 2022,published by MarketsandMarkets, the market is expected to reach USD 121.45 Billion by 2022, at a CAGR of 41.1% between 2016 and 2022.

The major factors driving this market are the growing demand for smartphone and other connecting devices, the increasing internet penetration, rising trends of industrial automation, and mainstream adoption of cloud computing.

A Brief Introduction of US largest Operator Verizon

Category : 其他, 技术相关

Verizon Communications, Inc. (simply known as Verizon), is a broadband telecommunications company and the largest U.S. wireless communications service provider as of September 2014, and a corporate component of the Dow Jones Industrial Average. The company is based at 1095 Avenue of the Americas in Midtown Manhattan, New York City, but is incorporated in Delaware.

 

What eventually became Verizon was founded as Bell Atlantic, which was one of the seven Baby Bells that were formed after AT&T Corporation was forced to relinquish its control of the Bell System by order of the Justice Department of the United States. Bell Atlantic came into existence in 1984 with a footprint from New Jersey to Virginia, with each area having a separate operating company (consisting of New Jersey Bell, Bell of Pennsylvania, Diamond State Telephone, and C&P Telephone).

 

As part of the rebranding that the Baby Bells took in the mid-1990s, all of the operating companies assumed the Bell Atlantic name. In 1997, Bell Atlantic expanded into New York and the New England states by merging with fellow Baby Bell NYNEX. In addition, Bell Atlantic moved their headquarters from Philadelphia into the old NYNEX headquarters and rebranded the entire company as Bell Atlantic.

 

In 2000, Bell Atlantic merged with GTE, which operated telecommunications companies across most of the rest of the country that was not already in Bell Atlantic’s footprint. Bell Atlantic, the surviving company, changed its name to “Verizon”, a portmanteau of veritas (Latin for “truth”) and horizon.

 

As of 2016, Verizon is one of three companies that had their roots in the former Baby Bells. The other two, like Verizon, exist as a result of mergers among fellow former Baby Bell members. One, SBC Communications, bought out its former parent AT&T Corporation and assumed the AT&T name. The other, CenturyLink, was formed initially in 2011 by the acquisition of Qwest (formerly named US West).

LTE CAT4/CAT6释义

Category : 其他, 技术相关

LTE CAT4/CAT6释义

  LTE CAT全名LTE UE-Category,拆开来解释, LTE指的是4G LTE网络、UE是指用户设备、Category翻译为等级。通顺解释就是用户设备能够支持的4G LTE网络传输速率的等级,也可以说成是4G网络速度的一个技术标准。所以LTE CAT4/CAT6就是指用户设备LTE网络接入能力等级为4或6。

  既然等级不同,那么其能力也肯定是不一样的,下面我们来看看LTE CAT4/CAT6影响了什么性能,分别是什么水平。简单来说,LTE CAT影响的就是4G LTE上行、下行网络速度的上限,通俗来讲就用户设备所能达到的上传、下载速度最大值。

r_4912859[1]

  在LTE CAT中不仅有4、6两个等级,上表是我们罗列的目前已知的LTE CAT等级以及对应的最大传输速度。其中LTE CAT4/CAT6也是目前4G手机的网络传输技术水平,而速度更快的CAT7和CAT8则仍处于实验室阶段,并未商用开发。

  

What is OpenWrt

Category : 其他, 技术相关

OpenWrt is an embedded operating system based on the Linux kernel, primarily used on embedded devices to route network traffic. The main components are the Linux kernel, util-linux, uClibc or musl, and BusyBox. All components have been optimized for size, to be small enough for fitting into the limited storage and memory available in home routers.
OpenWrt is configured using a command-line interface (ash shell), or a web interface (LuCI). There are about 3500 optional software packages available for installation via the opkg package management system.
OpenWrt can run on various types of devices, including CPE routers, residential gateways, smartphones, pocket computers (e.g. Ben NanoNote), and laptops. It is also possible to run OpenWrt on personal computers, which are most commonly based on the x86 architecture.
History
The project came into being because Linksys built the firmware for their WRT54G series of wireless routers from publicly available code licensed under the GPL. Under the terms of that license, Linksys was required to make the source code of its modified version available under the same license, which in turn enabled independent developers to create additional derivative versions. Support was originally limited to the WRT54G series, but has since been expanded to include many other chipsets, manufacturers and device types, including Plug Computers and Openmoko mobile phones.
Using this code as a base and later as a reference, developers created a Linux distribution that offers many features not previously found in consumer-level routers. Some features formerly required proprietary software. Before the introduction of OpenWrt 8.09, using Linux 2.6.25 and the b43 kernel module, WLAN for many Broadcom-based routers was only available through the proprietary wl.o module that was also provided for Linux kernel version 2.4.x only.
The code names of OpenWrt branches are named after alcoholic beverages, usually including their recipes in the MOTD as well, cf. White Russian, Kamikaze, Backfire, Attitude Adjustment, Barrier Breaker.
The bleeding edge development trunk was confusingly also called Kamikaze until February 2011 but with r25514 it was renamed as “Attitude Adjustment” and is now being constantly renamed to the next stable name.
Features
OpenWrt follows the bazaar-philosophy and is known for an abundance of options. Features include:
• A writable root file system, enabling users to add, remove or modify any file. This is accomplished by using overlayfs to overlay a read-only compressed SquashFS file system with a writable JFFS2 file system in a copy-on-write fashion. JFFS2 supports flash wear leveling.
• The package manager opkg, similar to dpkg, enables users to install and remove software. The package repository contains about 3500 packages. This contrasts with Linux-based firmwares based on read-only file systems without the possibility to modify the installed software without rebuilding and flashing a complete firmware image.
• A set of scripts called UCI (unified configuration interface) intended to unify and simplify the configuration of the entire system
• Extensible configuration of the entire hardware drivers, e.g. built-in network switches and their VLAN-capabilities, WNICs, DSL modems, FX, available hardware buttons, etc.
• Exhaustive possibilities to configure network-related features, like:
• IPv4 support.
• IPv6 native stack:
• Prefix Handling,
• Native IPv6 configuration (SLAAC, stateless DHCPv6, stateful DHCPv6, DHCPv6-PD),
• IPv6 transitioning technologies (6rd, 6to4, 6in4, ds-lite, lw4o6, map-e),
• Downstream IPv6 configuration (Router Advertisement, DHCPv6 (stateless and stateful) and DHCPv6-PD).
• Routing through iproute2, Quagga, BIRD, Babel etc.
• Mesh networking through B.A.T.M.A.N., OLSR and IEEE 802.11s-capabilities of the WNIC drivers
• Wireless functionality, e.g. make the device act as a wireless repeater, a wireless access point, a wireless bridge, a captive portal, or a combination of these with e.g. ChilliSpot, WiFiDog Captive Portal, etc.
• Wireless security: Packet injection, e.g. Airpwn, lorcon, e.a.
• Stateful firewall, NAT and port forwarding through netfilter; additionally PeerGuardian is available
• Dynamically-configured port forwarding protocols UPnP and NAT-PMP through upnpd, etc.
• Port knocking via knockd and knock
• TR-069 (CWMP) client
• IPS via Snort (software)
• Active queue management (AQM) through the network scheduler of the Linux kernel, with many available queuing disciplines. CoDel has been backported to Kernel 3.3. This encapsulates Traffic shaping to ensure fair distribution of bandwidth among multiple users and Quality of Service (QoS) for simultaneous use of applications such as VoIP, online gaming, and streaming media without experiencing the negative impacts of link saturation.
• Load balancing for use with multiple ISPs using source-specific routing
• IP tunneling (GRE, OpenVPN, pseudowire, etc.)
• Extensible realtime network monitoring and statistics through e.g. RRDtool, Collectd, Nagios, Munin lite, Zabbix, etc.
• Domain Name System (DNS) and DHCP through Dnsmasq, MaraDNS, etc.
• Dynamic DNS services to maintain a fixed domain name with an ISP that does not provide a static IP address
• Wireless distribution system (WDS) including WPA-PSK, WPA2-PSK, WPA-PSK/WPA2-PSK Mixed-Mode encryption modes
• OpenWrt supports any hardware that has Linux support; devices that can be connected (e.g. over USB) to an embedded device include
• Printers
• Mobile broadband modems
• Webcams
• Sound cards
• Notable software packages to use the hardware support are:
• File sharing via SAMBA, (Windows-compatible), NFS and FTP, printer sharing over the print server CUPS (spooling) or p910nd (non-spooling)
• PulseAudio, Music Player Daemon, Audio/Video streaming via DLNA/UPnP AV standards, iTunes (DAAP) server
• Asterisk (PBX)
• MQ Telemetry Transport through Mosquitto
• An extensive Ajax-enabled web interface, thanks to the LuCI project
• Regular bug fixes and updates, even for devices no longer supported by their manufacturers

 

Link to E-Lins OpenWrt Products:

http://www.e-lins.com/EN/download/H685_Datasheet_Eng.pdf

http://www.e-lins.com/EN/download/H820_Datasheet_Eng.pdf

http://www.e-lins.com/EN/download/H850_Datasheet_Eng.pdf

http://www.e-lins.com/EN/download/H860_Datasheet_Eng.pdf

E-Lins Frequently-used module parameters

Category : 伊林思产品FAQ, 技术相关

Supplier Module type Area Parameters
Ericsson F3307 UMTS/HSDPA/HSUPA: 2100/900MHz
GSM/GPRS/EDGE:1900/1800/900/850MHz;
Download Speed: 7.2Mbps;    Upload Speed: 5.76Mbps
Ericsson F3607gw UMTS/HSDPA/HSUPA: 2100/1900/850MHz
GSM/GPRS/EDGE:1900/1800/900/850MHz;
Download Speed: 7.2Mbps;    Upload Speed: 5.76Mbps
Ericsson F5521gw Global UMTS/HSDPA/HSUPA/HSPA+: 2100/1900/900/850MHz
GSM/GPRS/EDGE:1900/1800/900/850MHz;
Download Speed: 21Mbps;    Upload Speed: 5.76Mbps
Ericsson F5321gw Global UMTS/HSDPA/HSUPA/HSPA+: 2100/1900/900/850MHz
GSM/GPRS/EDGE:1900/1800/900/850MHz;
Download Speed: 21Mbps;    Upload Speed: 5.76Mbps
Huawei MU736 Global UMTS/HSDPA/HSUPA/HSPA+: 2100/1900/900/850MHz/AWS
GSM/GPRS/EDGE:1900/1800/900/850MHz;
Download Speed: 21Mbps;    Upload Speed: 5.76Mbps
Huawei MU709s-6 South America HSPA+/UMTS tri-band 850/1900/2100 MHz
GSM/GPRS quad-band 850/900/1800/1900 MHz
Huawei MU709s-2 Europe, Asia, Africa HSPA+/UMTS dual-band 900/2100 MHz
GSM/GPRS quad-band 850/900/1800/1900 MHz
Huawei MU609 HSPA+/UMTS quad-band 850/900/1900/2100 MHz
GSM/GPRS quad-band 850/900/1800/1900 MHz
Huawei ME909s-120 Most of Europe, Asia, Africa and South America LTE FDD: 2100/1900/1800/1700AWS/850/2600/900/800Mhz
(B1/B2/B3/B4/B5/B7/B8/B20)
3G: 850/900/1900/2100Mhz
2G: 850/900/1800/1900Mhz
Download Speed: 150Mbps;    Upload Speed: 50Mbps
Huawei ME909s-821 LTE FDD: 2100/1800/900Mhz  (B1/B3/B8)
LTE TDD: B38/B39/B40/B41
3G WCDMA: 2100/850/900/1700Mhz (B1/B5/B8/B9)
3G TD-SCDMA: B34/B39
2G GSM: 900/1800Mhz
Huawei ME909u-521 Most of Europe, Asia, Africa FDD LTE: 2600/2100/1900/1800/900/850/800Mhz (B1/B2/B3/B5/B7/B8/B20);
DC-HSPA+/HSPA+ /HSPA/UMTS: 850/900/1900/2100MHz(B1/B2/B5/B8),
EDGE/GPRS/GSM: 1900/1800/900/850MHz;
Download Speed: 100Mbps;    Upload Speed: 50Mbps
Huawei ME909u-523 US, South America LTE FDD: 1900/1700AWS/850/700Mhz(B2/B4/B5/B17)
DC-HSPA+/HSPA+ /HSPA/UMTS: 1900/1700AWS/850Mhz(B2/B4/5)
GSM: 850/900/1800/1900Mhz
Download Speed: 100Mbps;    Upload Speed: 50Mbps
Huawei ME906s-158 (M.2/NGFF) Europe, Asia and Oceania B28 LTE FDD:B1,B2,B3,B5,B7,B8,B20,B28
DC-HSPA+/HSPA+/HSPA/WCDMA:B1,B2,B5,B8
EDGE/ GPRS/GSM 1900/1800/900/850 MHz
Huawei ME906j (M.2/NGFF) Japan KDDI:
LTE: FDD Band 11, 18, all bands with diversity
CDMA 1X/CDMA EVDO Rev.B: BC0, BC6, all bands with diversity
GPS/GLONASS: L1
DOCOMO:
LTE: FDD Band 1, 19, 21, all bands with diversity
WCDMA/HSDPA/HSUPA/HSPA+: Band 1,5,6,19, all bands with diversity
GPS/GLONASS: L1
Huawei ME936 LTE (FDD) B1/B2/B3/B4/B5/B7/B8/B13/B17/B20
Penta-band DC-HSPA+/HSPA+/HSPA/UMTS B1/B2/B4/B5/B8
Quad-band EDGE/ GPRS/GSM 1900/1800/900/850 MHz
Sierrawireless MC7304 Most of Europe, Asia, Africa FDD LTE: B1/B3/B7/B8/B20  800/900/1800/2100/2600MHz(相对应为band 20/8/3/1/7)
WCDMA: 800/850/900/1900/2100 MHz(B6,B5,B8,B2,B1)
GSM 850/900/1800/1900MHz
Sierrawireless MC7354 US FDD LTE: 1900(B2), AWS(B4)
850(B5),700 (B13), 700(B17), 1900(B25)
UMTS/HSPA+: 2100(B1), 1900(B2), AWS(B4),850(B5),  900(B8)
CDMA EVDO/1x: BC0, BC1, BC10
Quad-Band EDGE/GPRS/GSM
Sierrawireless MC7350 US LTE: AWS(B4), 700(B13), 1900(B25)
CDMA 1x, EVDO Rev A:
BC0,BC1,BC10
Sierrawireless MC7330 Japan LTE: 2100 (B1), 850 (B19), 1500 (B21)
UMTS/HSPA+: 2100 (B1), 850 (B5) 800 (B6), 850 (B19)
Quad-Band EDGE/GPRS/ GSM
Sierrawireless MC7430 APAC FDD LTE:  B1, B3, B5-9,B18, B19, B21, B28                                                             TDD LTE:  B38,39,40,41                                                                                                    UMTS/HSPA+:2100(B1)  850(B5)/800(B6)/900(B8)/1800(B9)/850 (B19)
TD-SCDMA: B39(1900Mhz)
Sierrawireless ME3760 TDD LTE, LTE: 2600/2300/1900 (B38/B39/B40+B7);
TD-SCDMA: 2010~2025MHz/1880~1920MHz (B34/B39),
EDGE/GPRS/GSM: 1900/1800/900/850MHz;
Longsung U8301 Most of Europe, Asia, Africa FDD LTE: 2600/2100/1800/900/850MHz (B1/B3/B5/B7/B8)
DC-HSPA+/HSPA+ /HSPA/UMTS: 850/900/2100MHz (B1/B5/B8);
EDGE/GPRS/GSM: 1900/1800/900/850MHz;
Download Speed: 100Mbps;    Upload Speed: 50Mbps
Longsung U8300c TDD LTE: band38/39/40/41
FDD LTE: band1/3
TD-SCDMA: band34/39
UMTS: Band1
EVDO/CDMA1x: 800Mhz
GSM: 850/900/1800/1900Mhz
三旗 LM9206_ZAK Europe, Asia and Oceania B28 TDD LTE: band38/40
FDD LTE: band1/2/3/5/7/8/28
TD-SCDMA: none
UMTS: Band1/2/5/8
GSM: 850/900/1800/1900Mhz
三旗 LM9206_ZBK
(已经停产)
Most of Europe, Asia, Africa TDD LTE: band38/40
FDD LTE: band1/3/7/8/20
TD-SCDMA: none
UMTS: Band1/8
GSM: 850/900/1800/1900Mhz
Download Speed: 150Mbps;    Upload Speed: 50Mbps
三旗 LM9206_ZCK TDD LTE: none
FDD LTE: band1/2/5/7/8/28
TD-SCDMA: none
UMTS: Band1/5/8
GSM: 850/900/1800/1900Mhz
三旗 LM9206_ZDK Europe TDD LTE: band38/40
FDD LTE: band1/3/5/8
TD-SCDMA: none
UMTS: Band1/5/8
GSM: 850/900/1800/1900Mhz
三旗 LM9206_ZEK Europe, Asia TDD LTE: band38/39/40/41
FDD LTE: band1/2/3/5/7/8
TD-SCDMA: 34/39
UMTS: Band1/2/5/8
GSM: 850/900/1800/1900Mhz
三旗 LM9265 Europe, Asia TDD LTE: band38/39/40/41
FDD LTE: band1/3/5/7/8
TD-SCDMA: 34/39
UMTS: Band1/2/5/8
GSM: 850/900/1800/1900Mhz
CDMA/EVDO: BC0 800Mhz
ZTE ZM8620-A South America LTE TDD: band38
LTE FDD:2100/1900/1700 AWS/2600/850/900/700Mhz(B1/B2/B4/B5/B7/B8/B12)
DC-HSPA+/HSPA+ /HSPA/UMTS: 2100/1900/900/850/1700(AWS)Mhz
GSM: 850/900/1800/1900Mhz
Forge SLM630 TDD LTE: 2600/2300/1900 (B38/B39/B40/B41);
FDD LTE: 2100/1800/2600Mhz(B1/B3/B7);
DC-HSPA+/HSPA+ /HSPA/UMTS: 2100/1900/850Mhz (B1/B2/B5)
TD-SCDMA: 2010~2025MHz/1880~1920MHz (B34/B39),
EDGE/GPRS/GSM: 1900/1800/900/850MHz;
Download Speed: 100Mbps;    Upload Speed: 50Mbps
Forge SLM630b TDD LTE: 2600/2300/1900 (B38/B39/B40/B41);
FDD LTE: 2100/1800/2600Mhz(B1/B3/B7)
DC-HSPA+/HSPA+ /HSPA/UMTS: 2100/1900/850Mhz (B1/B2/B5)
TD-SCDMA: 2010~2025MHz/1880~1920MHz (B34/B39),
EDGE/GPRS/GSM: 1900/1800/900/850MHz;
EVDO/CDMA:BC0-800Mhz
Download Speed: 100Mbps;    Upload Speed: 50Mbps
LP41 FDD LTE, LTE: 450/800/1800/2600Mhz (B31/20/3/7)
Wetele WPD600N FDD LTE, LTE: 450/800/1800/2600Mhz (B31/20/3/7)

4G网络的语音解决方案

Category : 技术相关

4G商用已经有一段时间了。国内三家运营商各自使用的4G有些区别。 比如中国联通主要使用TDD LTE技术,而电信与联通主要使用FDD LTE技术。

目前4G主要有三种语音通话的解决方案:双待机、CSFB(Circuit Switched Fallback(电路域回落)和VoLTE(也及Voice over LTE)
1—-双待机:就是4G和3G/2G同时待机,4G用来上网,3G/2G则用来打电话,这种技术手机内部有两套射频发射系统,可想而知,这种技术,手机电池最多撑不到一天的,充电宝赚钱的机会是这样来的:)

2—-CSFB:就是通话时回落到2G模式(无法上网),通话结束后再恢复到4G/3G情况下,这种技术只使用一套射频芯片,现在我们4G测试主要是测试这种方案,毕竟4G网络还在建设中,有一些区域还没有完成覆盖到,这时切换很重要的。苹果用于电信的A1533的回落技术则另外取了一个名字叫做SRLTE,是一种特殊形式的CSFB。
—在国内,可以用DINGLI连三星和索爱的手机可以进行测试,有一些项目直接用IPHONE5S进行体验测试,在国外,主要用NEMO连三星,很少看到有用TEMS来测试!

3—-VoLTE:这种技术牛B呢,它是架构在4G网络上全IP条件下的端到端语音方案,接入时延大大提升,基本上没有掉话,以后肯定主要用这种技术了,毕竟2G时代快结束了,目前这种技术主要用于4G全覆盖的区域。
—测试软件方面,据说要用CHARIOT!

所以,严格的说,LTE网络只是数据网,在未实现VOLTE的情况下,LTE只能称之为3.5G,或是缺陷4G,只有包含了完美语音方案,不依赖2、3G网络的才能叫做4G网络。毕竟对于数据,语音还是很重要的。

SGLTE,SVLTE,SRLTE与CSFB的区别

Category : 技术相关

现在LTE已经广泛商用与三家运营商(中国移动,中国联通及中国电信)。 但是有些概念,我们需要分清下。比如SGLTE, SVLTE, CSFB及SRLTE。

SVLTE(Simultaneous Voice and LTE):即双待手机方式。手机同时工作在LTE和CS方式,前者提供数据业务,后者提供语音业务。

SGLTE (simultaneous GSM and LTE):LTE与GSM同步支持,终端包含了两个芯片。一个是支持LTE的多模芯片,一个是GSM的芯片。可以支持数据语音同时进行 。

SVLTE同SGLTE基本是一个概念,是一种单卡双待策略,手机插入一张卡,但可以同时工作在LTE网络和2/3G网络下(如果23G网络是CDMA,则是SVLTE,如果23G网络是GSM/UTRAN的,则是SGLTE),这样数据业务使用LTE网络,语音业务用23G网络。可以同时工作。

CSFB则是一种单卡单待的方案,终端只能工作在一个网络下,例如工作在LTE下,当有语音来电时,通过回落的方式回到23G网络下工作,因此采用CSFB方案4G网络和语音是不能同时进行的,注意这里说的是4G网络和语音不能同时进行而不是上网和语音不能同时进行,国内的3大运营商是有区别的,如下:
1.移动4G网络:
移动的3G网络就是移动的痛,移动的网络中当有语音来电时都会选择回落到GSM网络的,极少回落3G网络的,因为移动很清楚自己的3G网络无论是覆盖范围还是信号稳定度都很渣的。大家都知道2G网络不能在打电话的同时连接数据业务,因为移动4G语音回落2G会导致电脑断网的。

2.联通4G网络:
联通3G的WCDMA网络速度快,信号稳定,语音电话时会回落到42Mb/s的3G网络,WCDMA允许通话的同时连接数据业务,从这里可以看出,虽然联通的4G手机如果采用CSFB方案也不支持4G网络和语音同时进行,但是由于其回落到WCDMA网络允许通话的同时连接数据业务,因此语音通话时不会断网,但此时也不是工作在4G模式

3.电信4G网络
由于CDMA与LTE并不是一个体系中的技术,所以LTE语音通话要回落到CDMA,通话结束再返回LTE网络,电信就要在基站上做很大的改动,投入的资金较多的。全球的CDMA运营商都不会选择CSFB方案的。苹果采用了一种折中方案,会同时在CDMA 1x和LTE网络待机,这听起来有点像单卡双待,但CDMA 1x和LTE同时只能有一个进行数据的收发。如果有电话呼入,中断LTE数据业务,把电话接进来的。由于在CDMA 1x和LTE双待机,所以根本就不需要使用回落技术,只要调整阀门,关闭LTE数据收发,就能把通道腾出来,让CDMA 1x进行语音通信。
苹果的这种奇葩的方案,能够让C网运营商稍加改动网络协议就能满足iphone5的需求的,目前这种奇葩方案叫SRLTE。

综上所述,
1、如果终端设备采用的是SGLTE和SVLTE的语音方案,4G网络和语音都是可以同时进行的,不管哪个运营商。
2、采用CSFB的方案的终端设备,移动网络由于会回落到2G,2G又不支持不能在打电话的同时连接数据业务,因此会断网。而联通网络由于回到到的是WCDMA,因此因此语音通话时不会断网,但此时也不是工作在4G模式。
3、SRLTE,这个是专门针对电信CDMA网络的一个方案,采用这种方案的终端设备一样无法同时语音和数据,因此会断网。只有等电信部署好了SRLTE才有更好的体验度。

TDD LTE and FDD LTE

Category : 技术相关

As we know, the LTE mainly covers two types, which are TDD and FDD.  Let’s talk something about TDD LTE and FDD LTE’s Advantages / disadvantages of for cellular communications.

There are a number of the advantages and disadvantages of TDD and FDD that are of particular interest to mobile or cellular telecommunications operators. These are naturally reflected into LTE.

COMPARISON OF TDD LTE AND FDD LTE DUPLEX FORMATS
PARAMETER TDD LTE FDD LTE
Channel reciprocity Channel propagation is the same in both directions which enables transmit and receive to use on set of parameters Channel characteristics different in both directions as a result of the use of different frequencies
Paired spectrum Does not require paired spectrum as both transmit and receive occur on the same channel Requires paired spectrum with sufficient frequency separation to allow simultaneous transmission and reception
Hardware cost Lower cost as no diplexer is needed to isolate the transmitter and receiver. As cost of the UEs is of major importance because of the vast numbers that are produced, this is a key aspect. Diplexer is needed and cost is higher.
UL / DL asymmetry It is possible to dynamically change the UL and DL capacity ratio to match demand UL / DL capacity determined by frequency allocation set out by the regulatory authorities. It is therefore not possible to make dynamic changes to match capacity. Regulatory changes would normally be required and capacity is normally allocated so that it is the same in either direction.
Guard period / guard band Guard period required to ensure uplink and downlink transmissions do not clash. Large guard period will limit capacity. Larger guard period normally required if distances are increased to accommodate larger propagation times. Guard band required to provide sufficient isolation between uplink and downlink. Large guard band does not impact capacity.
Cross slot interference Base stations need to be synchronised with respect to the uplink and downlink transmission times. If neighbouring base stations use different uplink and downlink assignments and share the same channel, then interference may occur between cells. Not applicable
Discontinuous transmission Discontinuous transmission is required to allow both uplink and downlink transmissions. This can degrade the performance of the RF power amplifier in the transmitter. Continuous transmission is required.

 

Advantages and Disadvantages of 4G WIRELESS TECNOLOGY

Category : 技术相关

Today is the day of high data requirement in internet. In most field the wireless system is very widely used. Currently a number of technologies like 1G, 2G, 2.5G, 3G, 3.5G etc.  A new technology is introduced which is called as 4G technology.

Fourth generation wireless system is a packet switched wireless system with wide area coverage and high throughput. It is designed to be cost effective and to provide high spectral efficiency. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr. The high performance is achieved by the use of long term channel in both time termchannel in both time and frequency, scheduling among users and smart antennas combined with adaptive modulation and power control. Frequency band is 2-8 GHz. it gives the ability for world wide roaming to access cell anywhere.It uses OFDM (ortogonal frequency divisional multiplexing) and Ultra Wide Radio Band(UWB), and Millimeter wireless and smart antenna.4G uses a multi network functional device software which is very helpful for multiple user.

Advantages
-support for interactive multimedia, voice, streaming video, Internet, and other broadband services -IP based mobile system-High speed, high capacity, and low cost per bit. -global access, service portability, and scalable mobile services -Seamless switching and a variety of Quality of

-Better spectral efficiency. Service driven services.
- Better scheduling and call admission control techniques

Disadvantages
-Expensive and hard to implement
-bettery usage is more
-needs complex hardware

Conclusion
There is a need for next generation of wireless technology i.e. 4G which will be a platform for seamless technology providing widespread coverage, band width and power consumption with higher data rates (100Mbps, 150Mbps and 300Mbps, future will update to 1000Mbps, etc.).