Questions about CDMA2000, HSPA and WiMax

[geek_boy]

CDMA2000, HSPA and WiMax

1)If your service provider runs on CDMA2000, then is it necessary that it would also support HSPA and all other 3G features?

2)If WiMax and GSM networks, both use 900Mhz frequency spectrum for communication, then why don't the signals interfere?

3)Is WiMax really a good choise to be used as a common mobile phone? If it is, then I've heared that the reception at the very end radius of WiMax tower is not good enough, while of GSM is pretty good. Is it true?

Plz forgive me if questions sound stupid!

 

[kishore2k4]

Re: CDMA2000, HSPA and WiMax

1) IIRC, CDMA2000 and 3G are two very different standards though both of them are based on Direct Sequence Spread spectrum, they have different specifications.

2) Where did you get the idea that WiMax uses 900MHz? As far as I know the two major profiles are 2.3Ghz and 2.5Ghz with 3.x Ghz etc. WiMax 802.16e-2005 is only specified for frequeincies 2Ghz and upwards. There is some speculation that WiMax may be adapted for UHF frequencies considering that Analog Switch-OFF will vacate a lot of UHF spectrum but nothing has been standardised yet. The UHF spectrum may be used for future wireless services.

Also understand that GSM900 doesn't exactly operate at 900 Mhz, it uses two different frequencies below and above 900 Mhz for uplink and downlink.

3) WiMax is way more advanced than GSM and has adapatibiliy features for each and every user requirements. As far I know WiMax is meant for Wireless Broadband Access with possibility of VoIP but it has bigger problems. WiMax isn't designed to operate at high speeds (travelling speeds like in cars and trains). GSM works at 250km/h, WiMax not so much.

 

[geek_boy]

CDMA2000, HSPA and WiMax

IIRC, CDMA2000 and 3G are two very different standards though both of them are based on Direct Sequence Spread spectrum, they have different specifications.

CDMA2000 is a part of 3G networks, right? So they operate on almost same spectrum but have different specification. So which one in 3G supports HSPA? CDMA2000 or any other?

And also what are the major advantages you get for using a high frequency signal for transmission? specially in these cases?

 

[kishore2k4]

Re: CDMA2000, HSPA and WiMax

IIRC, CDMA2000 and 3G are two very different standards though both of them are based on Direct Sequence Spread spectrum, they have different specifications.

CDMA2000 is a part of 3G networks, right? So they operate on almost same spectrum but have different specification. So which one in 3G supports HSPA? CDMA2000 or any other?

And also what are the major advantages you get for using a high frequency signal for transmission? specially in these cases?

CDMA is sort of 2.5G/3G but not in 3GPP(GSM 3rd generation) but a seperate evolution of IS-95(cdmaOne). CDMA2000 is designed to operate in many frequency ranges including 2100Mhz used by 3GSM.

3GSM uses W-CDMA (Wideband-CDMA) and no they are not compatible. Just go through some articles are on the net and you can get a lore more information and their corresponding histories.