Rasp Pi electric mains control

http://electronicsforu.com/newelectronics/video/detailvideo.asp?id=2458

Rasp Pi with C

http://electronicsforu.com/electronicsforu/circuitarchives/view_article.asp?sno=2054&title+=+Raspberry+Pi+GPIO+Access+Using+C&b_type=new&id=13409&group_type=cool_stuff

Is Engineering field a dead end career in Singapore

http://www.quora.com/Is-the-engineering-field-a-dead-end-career-in-Singapore-Why

NEL Delay

http://www.channelnewsasia.com/mobile/singapore/north-east-line-delay/1707978.html?cid=FBSG

Microcontroller-Based Solar Charger

http://www.electronicsforu.com/electronicsforu/circuitarchives/view_article.asp?sno=475&title+=+Microcontroller-Based+Solar+Charger&id=4706&article_type=2&b_type=new&ss=+449521

Nokia and NTT DoCoMo targets 10Gbps 5G by 2020 Tokyo Olympics

Ref: http://fossbytes.com/nokia-ntt-docomo-reach-2gbps-speeds-5g-trial-mwc-2015/

Nokia and NTT DoCoMo Reach 2Gbps Speeds in 5G Trial: MWC 2015

BY ADARSH VERMA · MARCH 3, 2015

5G is going to be the next big revolution Wireless networking. At this year’s Mobile World Congress, 5G is a hot topic. The most advanced wireless technology being used currently is 4G which a major improvement was over 3G. But, 5G – the next big thing in the internet of things – is going to break all speed records.

At the ongoing Mobile World Congress, Barcelona, Nokia and NTT DoCoMo have teased an amazing 5G speed of 2Gbps. The companies have done this by using previously unused spectrum of high-frequency bands which includes millimeter waves. DoCoMo is Japan’s largest mobile operator and Nokia is world’s third biggest equipment maker.

Finland’s Nokia and Japan’s NTT DoCoMo are gearing up to showcase the technology at the 2020 Tokyo Olympics. They said that they’ll be giving a demo of their early progress of 5G radio equipment during the Mobile World Congress this week.

NTT DoCoMo’s chief technology officer, Seizo Onoe said, “We believe that high-frequency spectrum shall be used not just for small cells as a means to complement the existing network, but also for building solid area coverage through coordination with existing lower frequency bands. The success of this indoor trial with Nokia Networks using the 70GHz band marks an important step forward in our 5G vision for 2020.”

Image: CNet

The current 4G bands gives download speeds up to 300 Mbps, but the practical speeds seen are pretty lower. The 5G band from 10 to 100 GHz is expected to be freed for use by 2019 by International Telecommunications Union.

Nokia expects to see a 10,000 fold growth in data traffic in next twenty years and about 50 billion devices will be using mobile networks by 20125. Back in September 2014, Nokia made an announcement that it was trailing 5G in Finland.

Also, read about the Nokia’s comeback and its Nokia C1 phone and Nokia N1 tablet running on Android.

Qualcomm on 802.11ai

Ref: https://www.qualcomm.com/invention/research/projects/wi-fi-evolution/80211ai

Improving the Wi-Fi user experience.

Qualcomm is leading the way in developing IEEE802.11ai based technologies that significantly improve Wi-Fi user experience as well as address many Wi-Fi deployment pain points for operators.

Operators are increasingly relying on Wi-Fi to enable Cellular offload and offer Wi-Fi-as-a-Service. However, users often turn off Wi-Fi when they encounter an unsatisfying experience such as poor connectivity, long connection times, poor roaming experience, reduced bandwidth due to spectral inefficiency (excessive management frames), etc. Qualcomm Research has developed 802.11ai based technology to solve such issues which are pervasive in today’s public Wi-Fi networks.

Benefits of 802.11ai

·         Fast Initial Link Setup (FILS): Legacy Wi-Fi link setup in operator managed networks may require exchange of up to 27 messages between the STA, AP and Authentication Server. 802.11ai based FILS reduces the number of link-setup messages to 4, significantly improving link-setup speed and robustness, while also reducing signaling overhead. By using FILS, the initial link set-up time can be improved ~15x.

·         Fast Wi-Fi Roaming: Good user experience in operator managed Public and Community Wi-Fi networks requires fast and seamless roaming of STAs across APs with different SSIDs and Subnets. Legacy Wi-Fi link setup and roaming procedures either completely stall or cause a 9-10 second outage when roaming across different SSIDs and/or Subnets, thereby inhibiting seamless user experience and making it unsuitable for real-time voice and video applications. 802.11ai enables fast Wi-Fi roaming by assisting STAs to quickly choose and connect to the right AP, bringing the interruption down to less than ½ a second.

·         Increased Capacity: For users already connected to a Wi-Fi AP, the arrival of a large number of new users can cause what is known as “probe storms” and/or “association storms” and consequently lead to a temporary service outage. This is a common problem in busy train or subway stations and airports. Also, operators of dense Wi-Fi networks observe decreased capacity as 20-60% of the medium is occupied by management frames overhead.

802.11ai FILS and probe storm reduction techniques can significantly reduce the medium overhead attributable to probe requests/responses, beacons and link setup signaling, resulting in increased capacity and better user experience even as hundreds of new users try to access the Wi-Fi network.

·         Additional Operator Benefits: 802.11ai enables a flexible Wi-Fi deployment model for operators, with no need for a central AP controller. APs from multiple OEMs can be easily deployed and the network can be configured with different SSIDs and subnets while maintaining good user experience and roaming performance. Additionally, 802.11ai authentication methods are designed to eliminate interaction with and reduce load on operator HLR/HSS.

Related Videos

 https://www.qualcomm.com/videos/wi-fi-advanced-airbrush-overview

Qualcomm on 802.11ah

Ref: https://www.qualcomm.com/invention/research/projects/wi-fi-evolution/80211ah

Improving whole home coverage and power efficiency.

IEEE 802.11ah is a new PHY and MAC design that operates in the sub-one-gigahertz (900MHz) band. 11ah is intended to support extended range Wi-Fi, and the Internet-of-everything (IoE). The 11ah PHY and MAC are optimized from the ground up for extended range, power efficiency, and scalable operation. The new 11ah design enhances link-budget compared to 2.4GHz technologies. 11ah supports mandatory and globally interoperable 1 and 2 MHz bandwidth modes which open up new use cases for Wi-Fi: IoE, home automation, smart grid, wearable consumer electronics, low-power sensors, etc. 11ah also supports 4, 8, and 16 MHz bandwidths for higher-data rate applications (e.g. in the US where 26MHz is available in 900 MHz band). 11ah extends the range of Wi-Fi beyond the limited range of 2.4 and 5 GHz by leveraging the improved propagation and penetration of 900MHz radio waves through walls and obstructions. With 11ah, Wi-Fi coverage improves in previously hard to reach places such as garages, back yards, attics, buildings, factories, malls, etc.

A single 11ah AP can provide whole home coverage. It can also support low cost battery powered sensors operating without a power amplifier and which use interoperable 1&2 MHz bandwidth modes. A 150 Kbps minimum data rate results in short on-time for sensors with short bursty data packets thus lowering their power consumption. Overall power is also reduced by using lower power MAC protocols such as smaller frame formats, sensor traffic priority, and beaconless paging mode. 11ah MAC is also optimized to scale to thousands of nodes by using efficient paging and scheduled transmissions. 11ah leverages the Wi-Fi ecosystem & IP network for easy setup & pairing to AP/mobiles. 11ah devices are interoperable across vendors.

11ah is being standardized in IEEE with a draft 2.0 version expected in mid-2014. Our Wi-Fi Advanced, along with other participants, have been leading these standardization efforts.

Qualcomm on 802.11ac

Ref: https://www.qualcomm.com/invention/research/projects/wi-fi-evolution/80211ac

Pushing capacity and performance improvements.

IEEE 802.11ac is the next evolution of Wi-Fi—to push capacity into Gigabits-per-second in order to meet the 1000x challenge. 11ac mandates operation in the 5 GHz band where there is relatively less interference and more channels are available, compared to the 2.4 GHz band used by previous 11 a/b/g/n standards. 11ac uses wider bandwidth and up to eight spatial streams to achieve a maximum of 6.93 Gigabits-per-second theoretical throughput. 11ac also enables new use cases such as multiple HD video streams throughout the home by improving spectral efficiency.

With an ever-increasing number of Wi-Fi-enabled devices present in enterprise and home (i.e., higher attach rates) 11ac is the ideal evolution in the Wi-Fi standard, using advanced techniques that leverage spectral efficiency and higher bandwidth, ultimately providing needed capacity and performance gains. Qualcomm VIVE includes an entire ecosystem of 11ac solutions that will accelerate the transition to next-generation of Wi-Fi.

11ac is fully backward compatible with 802.11n. It operates in the 5 GHz band and uses up to 160 MHz bandwidth. In addition, it uses spatial division multiple access (SDMA) techniques to enable multi-user MIMO or MU-MIMO. Operating in 5 GHz band reduces interference and antenna size requirement, allowing for smaller antenna sizes for portable devices, leveraging wider bandwidths (20, 40, 80, and optional 160 MHz) and increases in data rates.

We have demonstrated MU-MIMO PHY operation running on a prototype 11n module with a MU-MIMO software overlay. Results showed a 3x improvement in PHY rates compared to 11n. This is shown in this video (link).

All of the above features have been standardized in IEEE under 11ac which are explained in this white paper (link). Qualcomm Research, along with other participants, lead the standardization efforts for these features.

Related Videos

https://www.qualcomm.com/videos/wi-fi-advanced-11ac

Related Documents

·        

IEEE802.11ac: The Next Evolution of Wi-Fi

824KB PDF 

Charge Only MicroUSB Cable (DCP - Dedicated Charging Port)

Ref: http://blog.seani.am/2011/08/charge-only-microusb-cable/

Charge Only MicroUSB Cable

 

I’ve been using either Verizon, Sprint, or AT&T’s mobile broadband service for over five years. I’m now on my fourth technology iteration and I have a hard time remembering what it was like when Internet was only available at home, office, and the café. I refuse to return to those dark ages!

Until recently I used Verizon’s first generation of MiFi hotspot, the Novatel 2200. It’s a great little device that did exactly what I wanted it to. When I needed it to be a WiFi hotspot, it was a hotspot. When I was on the road and needed to charge it via my laptop’s USB port, that worked perfectly as well. Recently however, my company upgraded me to the newest MiFi hotspot, the Novatel 4510L. For the most part the new device is faster, shinier, has better reception… it goes to eleven!

The problem is, and I consider this to be a design flaw, is that when you plug the device into a PC, with the USB cable provided, it will only charge the device. The 4510 will neither operate as a WiFi hotspot, nor will it operate as a USB connected modem. I learned this the hard way last week when I spent most of the day at the green mermaid coffee shop waiting for the mechanic to finish my car repairs. As it was a crowded day in laptop land, I only managed to get access to a single power outlet. When the batteries on my MiFi hotspot were nearly tapped, I had to resort to swapping between the laptop charger and the MiFi charger every hour to make it to my car pickup.

Armed with a soldering iron and heat shrink tubing, this was an easy hack. A USB cable has four wires; two for power, two for signal. If you cut open the cable and clip the signal wires, then you effectively create a charging cable. Based on a support forum thread at Verizon Wireless (http://bit.ly/pBqf1h), I also learned that you can trick the 4510L into thinking it’s attached to its AC charger if you additionally short the signal wires on the MicroUSB side. So, I closed the circuit on the green & white signal wires on the MicroUSB end of the cable. Important: The signal wires on the host or USB A end of the connection must remain open or you risk shorting out your USB port or damaging your computer.

Typical USB cable color coding: Red +5v, Black, GND, White Signal+, Green Signal-

Tie the power wires together, solder & insulate. In order to trick the Novatel 4510L into thinking it’s connected to its AC adapter, short the signal leads on the device or MicroUSB end. Be sure to leave the signal wires on the host end of the cable open. Insulate all of the wires with electrical tape or heat shrink.

Finished product. I only made the cable 6″ long so as not to add to the rats nest of cables that I already keep in my backpack.

[Update 2011-08-16 10:06 PDT]: According to Verizon Wireless, the shortcoming of not being able to charge and operate the Novatel 4510L while plugged into a PC USB port is a design constraint and not a design flaw. Many PC USB ports fall short of the 500mA power spec and do not provide enough energy to both charge the batteries and power the MiFi radios. My MacBook Pro happens to have enough juice (http://bit.ly/niXKgJ), so I feel it is safe to operate with my hacked cable. You may want to check the specs on your laptop’s USB ports before you proceed.

Ref: http://forums.androidcentral.com/asus-fonepad/291812-asus-fonepad-not-powering-up-2.html
1) Check the voltage across the battery. It shows nearly zero volts.(optional)
2) Now we have to charge the battery externally.
i) Remove the battery connector
ii) Cut any USB cable. Mostly you'll have 4 cores(Red, Black, Green and white) inside. Leave the green and white cores. connect the red cores to red terminal of battery and black to black.
iii) Connect the USB to ASUS charger and charge for 5 mins. You can check the voltage across the red and black terminals of battery while charging. It would be about 3V.
3) Now disconnect the charger and check the voltage across the red and black terminals. It will show about 3V.
4) Now connect the battery connector to tablet and connect it to a charger. Now the tablet starts with zero battery icon followed by battery charging indication.
5) Charge the tablet for some time and switch it on.