zanny :
Absolutely. The USA is backwards in few things. Healthcare, measurement units, and CDMA. The rest of the world has adopted ETSI standards rather than some proprietary <mod edit>. If AT&T was not the absolute worst company in the world (tied with Verizon, Comcast, Disney, Haliburton... and others) they would be a much better choice because they use the international standard networking tech rather than ancient crap.
Um, you know CDMA won the GSM vs CDMA war, right? Most implementations of 3G on GSM use CDMA or wideband CDMA.
https://en.wikipedia.org/wiki/3G#Break-up_of_3G_systems
See, GSM originally used TDMA - time division multiple access. Basically each phone communicating with the tower got a timeslice, and the tower cycles through each phone with an active voice or data connection one at a time. The problem is, each phone gets an entire timeslice regardless of whether or not it needed the full timeslice to transmit data, or even if it didn't have any data to transmit. This resulted in a lot of GSM data bandwidth being wasted. If a dozen GSM phones were maintaining a data connection, the most any single phone could ever get was 1/12th the total bandwidth. Even if all 11 other phones weren't transmitting data at that time.
CDMA (code division multiple access) doesn't dedicate a timeslice or frequency to a single phone. All phones can transmit simultaneously. The tower tells them apart by the orthogonal codes they use. Kinda like writing one message horizontally on a piece of paper, another message vertically. As long as the codes (letters) are distinct (orthogonal), you can tell them apart even though they're overlapping. So data bandwidth on CDMA scales automatically. If only a single phone is transmitting, it can use all the available bandwidth. If a dozen phones are transmitting, each phone sees the transmissions of the other 11 phones as noise, and its bandwidth gets shrunk to 1/12th the total bandwidth due to a lower signal to noise ratio. if one of those phones finishes its data use and stops transmitting, the noise level drops slightly and the remaining phones each automatically get 1/11th the total bandwidth. In CDMA, all the bandwidth is used all the time, and when multiple devices are transmitting the technology by its very nature gives each phone a proportional share of the bandwidth.
There's no way GSM could compete with that, so they were forced to license CDMA and implement it to stay competitive with CDMA data speeds. They were just too butt-hurt about it to call it CDMA, so instead they named it UMTS or HSPA or HSDPA. That's why GSM phones could talk and use data at the same time - they have a TDMA radio for voice, and a separate CDMA radio for data. The old CDMA phones couldn't do that because they only had a single CDMA radio which could only operate in voice mode or data mode, but not both simultaneously. If you think back to when we transitioned to 3G, CDMA got 3G speeds about a year before GSM networks did. Because GSM had to license CDMA, create new specs, and make new phones with CDMA data radios.
Most LTE implementations use OFDMA - orthogonal frequency domain multiple access. Like CDMA, it uses orthogonality to use 100% of the available bandwidth. Except instead of using orthogonal codes, it uses orthogonal frequency allocations. It requires more processing power than CDMA, which is why it matured later. The processors needed to decode OFDMA required so much power that until the last few years it would've drained a cell phone battery too quickly. WiMAX used OFDMA, and my old 2010 phone which could go 12+ hours downloading over 3G would die in 4-5 hours on WiMAX.
If the U.S. hadn't been stubborn about allowing CDMA and had instead forced the adoption of GSM, our phones would probably be stuck at 2G data speeds today. Competition is wonderful for correcting stupid decisions made by bureaucrats who are clueless about the actual technology they're creating standards for (enshrining TDMA as the "global" standard).
alextheblue :
Agreed. This isn't about the technology, but about how Verizon (and Sprint to a lesser extent) use it. You can't just stick a phone on a CDMA network without the carrier explicitly allowing it. They make it extremely difficult to get any outside phones on their network, even if they are CDMA-capable and support all the right bands. If you try to force the issue they can delay and stall you almost indefinitely and at great financial cost. That's why MS opted not to enable the CDMA bits in the 950 series.
Sony doesn't put out CDMA versions of their phones either. One of the nice things about the Nexus phones is that there is no GSM vs CDMA version. They all support both GSM and CDMA. (Some do have an International vs U.S. version, with different LTE frequencies supported to reflect which LTE bands are used most often in each country.)
silbaco :
Verizon already did rethink their business model when they decided to adopt LTE. Shutting down the CDMA network which currently serves over 100 million devices to transition to GSM is not in anyone's best interest. It would cost both Verizon and consumers billions and would serve no purpose when everything is transitioning to full LTE anyway. Traditional GSM and CDMA networks are being phased out so all spectrum can be refarmed for LTE/VoLTE.
See above. OFDMA (LTE) is more efficient than CDMA (allows faster signaling, thus higher speeds). If DSPs were low-power enough back in the 2000s, we probably would've jumped straight to OFDMA instead of CDMA since conceptually and mathematically they function the same way. But DSPs didn't drop in power consumption enough until about 2012-2013 for OFDMA to really be practical with the size battery found in most cell phones.
Agreed that voice over LTE or voice over the next thing will be the future. Same as how VoIP has gradually been taking over landline phone networks (Vonage, Ooma, Magic Jack, etc).
Facebook
Twitter
Instagram