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Friday, November 23, 2012

AnandTech Article Channel

AnandTech Article Channel

Nexus 4 Includes Support for LTE on Band 4 (AWS)

Posted: 23 Nov 2012 01:40 AM PST

I noted in my review of the LG/Google Nexus 4 that the device included hardware necessary for LTE on at least some of its bands, namely bands 1 (2100 MHz), 2 (1900 MHz), and 4 (AWS 1700/2100) based on what I saw in my teardown. Enabling LTE on a given device requires everything in the cellular chain to include support — the cellular baseband to support it must be present and loaded with the appropriate software, the transceiver must be the appropriate kind, and finally the right power amplifiers (PAs) have to be in place for the wider channel bandwidths that LTE brings (up to 20 MHz) over WCDMA  (5 MHz). 

 
Nexus 4 on Band 4 LTE (Left), Band Preference Setting in *#*#4636#*#* (Right)

In the case of the Nexus 4, the hardware includes the latest and greatest cellular hardware from Qualcomm with MDM9215M, its third generation 28nm Category 3 LTE multimode baseband, and a WTR1605L transceiver. I tore down the Nexus 4 to ascertain whether PAs were present that could work with LTE, and saw indeed that at least bands 4, 2, and 1 did have Avago power amplifiers (A5704, A5702, and ACPM–7251) which noted support for LTE. The remaining piece of the puzzle was software stack, both in Android and inside the version of the AMSS (Advanced Mobile Subscriber Software) running onboard MDM9215M.

Recently some Nexus 4 owners in Canada posted on XDA that they had working LTE support on Band 4 if they enabled the appropriate "Preferred Network Type" in the dropdown menu there. This menu is inside "Phone Info" which has been part of Android forever and can be accessed on almost every Android phone either by dialing *#*#4636#*#* (INFO) or using an app called Phone Info which launches that activity directly. 

Recently, Anritsu graciously loaned me an MD8475A signaling tester and LTE/WCDMA/CDMA2000 base station emulator for me to test and evaluate devices with. I tested the Nexus 4 on DC-HSPA+ for the review but didn't think to try testing LTE on the appropriate bands since Google and the FCC documents are both explicit about only WCDMA/GSM being present. I tested for LTE on all the bands that the Nexus 4 includes UMTS support for, starting with 5 MHz wide LTE channels. It appears that Nexus 4 only has support for LTE on Band 4 (AWS) with bandwidths up to 20 MHz in fact. I put together a table for easier parsing. If a band isn't listed, it isn't supported.

Nexus 4 LTE Band Coverage
E-UTRA (LTE) Band Number Commonly Known Frequency (MHz) Bandwidths Supported
1 2100 No Support
2 1900 No Support
4 1700/2100 5, 10, 20 MHz
5 850 No Support
8 900 No Support

Because testing the 2x2 MIMO configuration requires cabling up the Nexus 4 to the antenna leads directly, and my LG-appropriate antenna connectors haven't arrived yet, I only can test with a 1x1 configuration. The Nexus 4 does include Rx diversity for every band, and thus it's entirely possible on Band 4 that users will see the full 2x2 MIMO rates (37 Mbps on 5 MHz, 73 on 10 MHz, 100 Mbps on 20 MHz), but I can't confirm it directly. For the 1x1 configuration I could test, however, I saw the expected ~75 Mbps on 20 MHz FDD LTE which is very close to the maximum of 75.376 as shown. 

The conclusion is that the Nexus 4 at present curiously includes the software profile on MDM9215M that enables support for LTE on Band 4 (AWS), and users only need to set the appropriate network type preference in Android to use it. None of the other bands that there are even power amplifiers for have LTE support, which is unfortunate for users in places where carriers aren't running LTE on AWS, such as the USA. For example, in the USA, AT&T previously discussed plans for LTE on Band 4 but has only rolled out LTE on Band 17 to date, and is rumored to be turning to refarming its PCS (1900 Band 2) and Cellular (850 Band 5) holdings for additional LTE capacity, perhaps in the stead of AWS. T-Mobile US however will use AWS for LTE. Nexus 4 LTE support is definitely unofficial (and somewhat surprising) at this point, but if you're lucky enough to be in a place where your carrier has rolled it out on Band 4, it's just a setting away.

Source: XDA Developers

Fractal Design Node 304 mITX Case Review: Paving the Way to the Future

Posted: 22 Nov 2012 08:01 PM PST

We've said it before but it bears repeating: desktop systems are getting smaller. ATX is becoming less and less necessary, and mini-ITX-based machines more and more offer the same performance and features that their bigger brothers do. That's just the direction of the technology industry as a whole, cramming everything we need into a space half as large. What's specific to cases is their own evolution running parallel with the technology we're putting into them.

Fractal Design's Node 304 is in many ways a surprising jump forward in case design. We've seen SilverStone, BitFenix, Lian Li, and Cooler Master all try their hands at mITX cases with varying degrees of success, but there's just no set design language when you get down this small. The conventions we take for granted in ATX case design don't really apply here, but Fractal Design has tried for something fairly different with the Node 304, even by mITX standards. Read on to find out where they've deviated from an already unpredictable design language.

Patriot Gauntlet Node 320 Review: Wireless Storage for Tablets

Posted: 22 Nov 2012 11:08 AM PST

One side effect of the current march towards ultramobility is the nearly complete abandonment of expandable/upgradeable local storage. No modern smartphone or tablet allows for upgradeable internal storage, and it's not exactly common to find microSD slots or USB ports on them either. This is particularly a problem if you're shopping with Apple, where expandable storage has never been a part of the iPhone or iPad. As a result, you're encouraged to buy enough storage to last you until the next upgrade - as well as rely heavily on cloud based storage and streaming services.

Huge amounts of high performance NAND can be pricey. Modern SSDs are finally below the $1/GB price point, which when applied to a tablet should mean that the difference between 16GB and 32GB of storage is no more than $20. The reality however is far worse. NAND costs even less than the ~$1/GB that we pay when buying an SSD, and manufacturers tend to charge anywhere from $50 for 16GB to $100 in the case of Apple. For lower cost devices there may not even be higher capacity versions. All of the sudden that simple solution of just buying as much storage as you need up front becomes a lot more complicated. If you take into consideration the fact that smartphones and tablets are quickly replaced with much better versions, there's a good chance that you'll want a new device before you run out of storage if you buy the largest capacity offered.

A number of players in the storage industry have recognized this problem and are attempting to find the perfect solution. Just like there's still movement in determining the best mobile form factor, there have been a lot of early attempts to get wireless external storage for mobile devices right. We covered some of these in the past (e.g. Kingston's WiDrive and Seagate's GoFlex Satellite) but more recently Patriot Memory threw its hat into the ring with the Gauntlet Node and the Gauntlet Node 320.

Crucial v4 (256GB) Review

Posted: 22 Nov 2012 09:01 AM PST

As with virtually all consumer electronics devices, there is market for various types and levels of SSD. Not everyone is ready to pay the premium for the fastest possible SSD but on the other hand, there are users who aren't ready to settle for products meant for the mainstream. Value SSDs have existed for years and we have seen various outcomes, some good and others not so good.

Today we're looking at Crucial's v4, the first value SSD from Crucial. Previously, Crucial's lineup has only consisted of one SSD at a time but that changed when Crucial launched the v4 but kept selling the faster m4 alongside. The v4 uses a somewhat unknown (at least for desktop SSDs) Phison PS3105 controller, which is in fact a SATA 3Gbps controller unlike most modern controllers. Read on to find out how the v4 performs and whether it's worth it to cheap out on an SSD.

SandForce TRIM Issue & Corsair Force Series GS (240GB) Review

Posted: 22 Nov 2012 09:00 AM PST

SandForce and TRIM—that has always been a tricky combination. SandForce SSDs have always behaved a bit differently when tortured and TRIM'ed due to their internal design. When a non-SandForce SSD is tortured, write speed degrades and sooner than later you will end up with a read-modify-write situation. SandForce, on the other hand, uses a real-time compression engine which minimizes NAND writes; thanks to that, write speed doesn't degrade when the drive is tortured with easily compressible data. However, in exchange, read speed is affected if the drive is tortured with compressible writes. Incompressible data will also push SandForce to a corner as it can't take advantage of compression, and that's a corner even TRIM can't pull the drive out of.

Quite a few new SandForce SSDs are using a newer 5.0.x firmware, which does not have a fully working TRIM. Some are still using 3.x.x firmware without the TRIM issue but if you have a SandForce SSD that was recently released, there is a good chance its TRIM is broken. To test the TRIM issue, we used Corsair's new Force GS SSD with firmware 5.0.2, and Corsair was also kind enough to send us the 5.0.3 firmware that supposedly fixes TRIM. Read on to find more about the TRIM issue and how Corsair's Force GS performs.
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