Friday, December 16, 2011

How much do you know about 3G and CDMA? (part 1)

Below you can find a 10 questions regarding 3G. From these questions you can determine the level of your knowledge in that field, because many of you might feel that he/she needs to learn more about 3G network or the person who is not sure of how much he/she knows regarding this topic so i will start by this pre-test to determine your level of knowledge and later on i will provide some tutorials that would strengthen your 3G background.

now concentrate and try to answer these questions.
 1) CDMA is an acronym for which of the following:
a) cellular division multiple access.
b) code domain multiple application.
c) cellular domain multiple application.
d) code division multiple access.

2) A mobile radio system is assumed to consist two fundamental network elements which are:
a) UTRA, core.
b) radio access, core.
c) radio access, system.
d) UTRA, backbone.

3) CdmaOne is considered a technique from the:
a) 2nd generation.
b) 3rd generation.
c) 1st generation.

4) Which standard body is responsible for global 3G standardization :
a) CCITT.
b) ITU-R.
c) ETSI.
d) ANSI.

5)  A number of interfaces have been standardized  between the various network elements for UMTS. What is the  interface between the UTRAN and core network which implements the functional split between the access network and the core network.
a) Iu.
b) Iub.
c) Iur.
d) UTRA.

6) Which standard does CdmaOne IS-95 define?
a) core network.
b) air interface.
c) base station functionality.
d) mobile station functionality.

7) What is the equivalent term for a BTS ( Base transceiver station) in 3G?
a) RNC.
b) SGSN.
c) NODE B.
d) MSC .

8) What does the acronym UTRA mean:
a) UMTS Telephony Radio Access.
b) Universal Telephony Radio Access.
c) UMTS Terrestrial  Radio Access.
d) Universal Transmission Radio Access.

9) The WCDMA is technique employed  by UMTS on the air interface uses direct sequence spreading with a nominal bandwidth of 5MHz. this allows the data rates of _____ and _____ to be achieved, in fact data rates up to _____ can be provided under limited conditions.
a) 64kbps, 128kbps, 384kbps.
b) 128kbps, 144kbps, 1.5Mbps.
c)144kbps, 384kbps, 2Mbps.
d)384kbps, 1.5Mbps, 2Mbps.

10) The ITU-R made (recommended) two frequency band available for 3G these two bands are:
a) 890-915 MHz, 935-960 MHz.
b) 824-849 MHz, 869-894 MHz.
c) 810 - 825 MHz, 940 - 965 MHz.
d) 1885 - 2025 MHz, 2110 - 2200 MHz.


Now after finishing answering these questions you can check the answers in the bottom of this post and then determine your knowledge level. This is would be a great start because now you know how much more you need.

Hope this would help you in your studies and / or work. And as I've said in the future i will post more tutorials to cover this topic and anyone who needs anything or needs extra tutorials can email me and i will do my best to help.


Answers 1 - D, 2 - B, 3 - A, 4 - B, 5 - A, 6 - B, 7 - C, 8 - C, 9 - C, 10 - D

Wednesday, December 14, 2011

Is Wireless Technology Invading Laser Frequencies?

Rohm a Japanese semiconductor company  has created a 1.5mm X 3mm semiconductor with an antenna, this chip can transmit 1.5Gb per second but that's not it, Rohm is planning to reach 30Gbps.

For those who doesn't understand these numbers your current wireless router can deliver data with speed up to 300Mbps (theoretical value for IEEE802.11n), which means that this chip -so far- can deliver data 5 times faster than your current wireless router.

But what is the secret behind this very high data rate for such a small chip? The answer is using high frequencies and that's actually what Rohm did, they have used frequencies between (300GHz - 3THz) for transmission and reception of data. which will offer fast transmission and large bandwidth and eventually higher data rates.


As it is known the higher the frequency is the more directional the signal becomes and the less the ability to penetrate materials, this means that this chip -which works in terahertz band (same frequency range of the light)- needs line of sight to communicate with others and cannot penetrate water nor metallic materials, in other words this chip would work in device to device communications such as ad-hoc connections but won't replace the current 2.5 - 5 GHz wireless connections.

Rohm company says that the chip should cost less than $5 and it should come to market in few years, so from now on when we talk about terahertz it's not only lasers we are talking because wireless technology has invaded this frequency band.