06/06/2011
Network World
The 2011 Marconi Prize, sometimes described as the Nobel Prize in Information Technology, has been awarded to two major contributors to cellular communications: Qualcomm Co-founder Irwin Jacobs and the late information theorist and professor Jack Wolf.
Jacobs and the family of Wolf will split the $100,000 prize that comes with the honor given annually [...]
It’s a jargon engineers or physicists are using.
It’s a promise.
It’s about describing a ratio between two quantities.
How big is the one compared to the other?
For example, Chan’s height is 40 inch and Han’s height is 80 inch.
Han is two times higher than Chan.
Using dB, we say
10 log (p2/p1) = 10 log 2 = 3 dB [...]
02/18/2010
Associated Press (AP)
n this Feb. 17, 2010 file photo, a man walks past a banner at the Mobile …
By Peter Svensson, AP Technology Writer
BARCELONA, Spain (AP) — Silicon Valley is looking like a winner in the tug-of-war with wireless carriers over who will control the new world of Internet-connected phones.
The tension between the largely U.S.-based [...]
For high data rate, simply send fast.
Which one is high data rate ? 2 bits for 1 second vs. 2 bits for 6 seconds.
So, if you want a high data rate, your sending rate should be fast.
Time and frequency relationship is reverse. Short time duration means wide bandwidth.
That’s why wide bandwidth is need for faster [...]
First, think about the definition of spreading factor (SF): the number of chips for each symbol.
Second, remember that a chip duration is fixed.
Third, what is symbol? Each symbol can represent some amount of bits. e.g., QPSK, each symbol represents 2 bits.
SF: 2 SF vs. 512 SF
Time: 2*delta vs. 512*delta
Data: 1 symbol vs. 1 symbol
where delta [...]
