Currently viewing the tag: "US Cellular"

 I was looking at the Press Releases from US Cellular regarding their LTE market launches. You can see them here. Anyway the key things to me were, firstly the where…. 

The November rollout expands the 4G LTE footprint in select cities in Iowa, Wisconsin, North Carolina and Oklahoma, and brings 4G LTE coverage to some of U.S. Cellular’s leading markets in Illinois, Maryland, Missouri, New Hampshire, Vermont, Virginia and West Virginia. The next wave of market launches will follow shortly in Rockford, Ill., Medford, Ore., Yakima, Wash., and Knoxville, Tenn.

And this…the how…

King Street Wireless, L.P. currently holds 700 MHz wireless spectrum in 27 states and is partnering with Chicago-based U.S. Cellular to deliver high-speed 4G LTE service to U.S. Cellular’s customers in several of the carrier’s markets

So I was looking at some of these areas, and yes, there are Channel 51 DTV interferers in some of the same areas.

 Random pick, how about West Virginia? 

power | 15 kW  (kilowatts)  (effective radiated power)
height above average terrain | 0 feet
height above ground level | 187 feet
height above mean sea level | 1106 feet
directionality | directional
Yikes!

As you will note from the chart, there is a 15KW transmitter at Channel 51, so huge interference with the lower 700MHz UEs…  So looking a little closer at the spectrum ownership, they have a B channel/block in that market. So all this wind up to say:

1) Kudos to US Cellular for deploying lower 700MHz LTE

2) Unlike what Qualcomm was trying to convey in their report to the FCC, US Cellular is using the lower 700MHz Channel B without issue, probably some sharp eNB filters are helping out.

 It’s time for the rest of the market to jump in and play here. 700MHz LTE is a game changer based on the rich variety of spectrum owners and owing to the physics that the propagation of 700MHz channel is great compared to the typical 1900MHz or 2100MHz channels used for 3G. 

Keep up the good work US Cellular.

 Oh yeah, they have a cute video too. Check it out. :)

 Here are some thoughts about the questions I get around SVLTE.

Notice the pic and remember this day? This was Verizon and Apple answering questions about the iPhone 4. The biggest technical tidbit of the day was that the 3G iPhone 4 would not allow a simultaneous voice and data session. Of course this was dictated by the 1X CDMA network architecture, not the phone.

Here is a good graphic sort of illustrating that difference.  


Yes, The same issue exists for LTE and CDMA voice!

See, there is a confusion based matrix of items to enable the use of data during a voice call. There is some technical detail to get into to understand what the problem is.

Some of the blame goes to the phone OS, some the phone HW and some is on the network.

HSPA/WCDMA 3GPP networks like ATT and Tmobile support this feature and so the remainder is inside the mobile device. 3GPP2 based Verizon and Sprint on the other hand don’t have this capability inherently in the network. 

 

UE (Mobile Device) UI Capability/function

The device User Interface (UI) manages the integration of voice and data services for us. As you know, for example, the iPhone visually displays a dial pad for voice calls and has other apps for data like browsers, email, FaceTime/Skype etc… Not so obviously, the multitasking nature of the UI and Operating System  that supports multiple execution threads etc, facilitate and encourage data use such as it is so convenient. The interface makes it easy to switch between these tasks and actually encourage parallel data/voice simultaneous use. So Smartphone = Attention Deficit Disorder (ADD) device.

UE (Mobile Device) Hardware (HW)

Beyond the user interface, the device needs to be enabled with the capability to transmit data and voice simultaneously (or apparently so.)

Many USB based devices are data only (much like the old flip phones were primarily voice only) and only have HW to facilitate a data transmission. No voice HW present, but no need either. Result is simple and cheaper device. Smartphones sort of beg dual use, and often have HW to support data transmission and voice encoding/transmission. Now for the caveat (confusing part), of course it’s possible to have a data application for voice like Skype and that would technically eliminate the need for separate HW however the first deployments in the US are only partial data overlays over extensive voice networks, thus most devices base their connectivity on 3G voice and need to have voice compatible HW onboard for those non 4G or 3G data covered areas. Secondly, the quality of voice in voice networks is currently more assured, or higher priority than the existing non assured data services. So in the case of Skype over 4G, your voice packet gets the same priority (currently by default) as my web browsing packet. (With the PCRF this doesn’t have to be true but operators have not really unleashed this tiered type of service over LTE yet.)

So hardware wise, UEs utilize (baseband) processors capable of 3G to in addition to LTE to be capable of communicating with both networks. The first devices had 2 chipsets, 1 for 3G processing and a second for LTE processing. Only recently has there been multi generational (and multi protocol) capable chipsets that are able to process both 4G data and 3G in one chipset. 

To be clear, a device that has a single RF/baseband processing path may only be communicating on one network at a time.

Here is a typical data + voice capable device architecture showing Qualcomm components. 

So if the processing is in place, the next thing in the chain is the Radio Frequency (RF) chips. You can’t physically interface to the network without the capabilities here so it’s essential for the device to be able to interface to the voice and data spectrum bands and modulate/demodulate the signals correctly. This whole subject is so deep, more in a follow up post on this.

 Qualcomm is arguably the market leader in UE components and architecture. The pictures are the previous MSM8960 components which were 2 pieces of silicon for 3G and 4G processing and others for RF. The MSM9600 chipsets that are shipping now are essentially 1 piece of silicon for 3G and 4G processing with a second for the RF interface.

UE Network Communication Protocol

In the US, MetroPCS, Sprint, US Cellular, Verizon are networks that utilize CDMA 1X technology. 1XRTT (IS-95)/CDMA2000 or 3GPP2 based voice is a circuit switched voice protocol, with all the bells and whistles of 1.25MHz channels, RCs, Walsh codes, PNs etc… For high rate data, these networks utilize 1xEVDO (Evolution Data Only) a code and time division protocol and have slots, 1.25MHz channels, DRCs and so on. In summary, CDMA2000 uses 2 separate radio channels with 2 protocols for data and voice communications. ATT, T-Mobile and others have deployed 3GPP based WCDMA networks with 5MHz channels for voice and HSxPA with 5MHz channels for high rate data. 

Just to be doubly confusing, functions and G’s aren’t necessarily the same. There is 3G high rate data and 4G high rate data, and there is 4G voice and 3G voice. 

The communications protocols for voice on 3G on CDMA networks uses Qualcomm’s EVRC (Enhanced Variable Rate Coder) and on WCDMA networks is AMR (Adaptive Multi Rate) coding. The coding converts sound to data bits. Just to stay confusing, 4G voice, under the Voice over LTE (VoLTE) framework uses AMR also, but the rest of the voice protocol is very different than 3G. 

Data story is similar with 3G high rate data on 1X CDMA 3Gpp2 based networks is EVDO (now Rev A is most common) and on WCDMA 3GPP based networks is HSPA (now HSPA+ is becoming the most common.) For 4G we will only focus on LTE which happens to be 3GPP based.

There’s a lot of complexity in communicating the bits back and forth from the network when you compare 3G and 4G and CDMA 1xRTT with WCDMA/HSPA. Due to technical and cost constraints, most devices up to date have been either CDMA 3GPP2 capable or WCDMA 3Gpp capable. As an example, Qualcomm Gobi based devices have support for just about every situation in one component whereas Marvell only supports 3G WCDMA/HSPA and LTE.

A strong desire exists for every device to support every scenario, however the complexity and risks sort of dictated this approach of multiple networks, separate devices. See this seamless mobility chart, key point is you need both protocols, 3G and 4G for now.

 

Wireless mobile networks have had this multilayered architecture to support 3G circuit switched voice and high rate packet data at the same time for a while now. Adding in LTE is another layer of complexity that manifests itself as a battery and size constraint for today’s UE designs (more HW + more communicating layers in the devices), and in fact Steve Jobs specifically mentioned it as a barrier to LTE implementation in the iPhones.

UE Parallelism/simultaneous use

So now we are clear a device that has a single baseband processing path may only be on one network at a time. That was very long windup and I apologize. Back to the problem of the Verizon iPhone vs the ATT iPhone and voice and data simultaneously…

A mobile device that only supports a single network (voice or data) device will have to pause communicating with the data network if a voice call is to be made or received and vice-versa.  

The first generation of 3G/LTE capable devices have 2 physical components, a 3G path processor and a LTE path processor.  Qualcomm, TI, Marvell and others are beginning to ship components to enable the 2nd generation of LTE devices, those with 2 paths and shared silicon (fewer components.) The first devices are hitting the shelves. The benefits will be improvements to battery life and form factor, however neither will be as best they can be yet. Have a look at a slide from Qualcomm presentation comparing various architectures based on heat (energy waste) output. So it takes 2 radios to have a 3G and LTE flow from the device at the same time in order to support true simultaneous data and voice use.

 

 

 

 

 

 

 

 

 

 

 

The next step in device design will either be VoLTE and/or a software defined radio approach that allows more effective conservation of resources but that’s a topic for another day. Back to voice+data.

 

 

OK so the ability to make 3G voice calls and use data at the same time can be broken into smaller pieces.

  • For 3G 1X or 3GPP2 based networks like Sprint, Verizon, MetroPCS etc…, 1X (voice) + EVDO (data) is called SVDO. Some devices support this but most networks do not…As an example, the Verizon iPhone either communicates data or voice at one time.
  • For 3G WCDMA or 3GPP based networks, the voice and data bearers can be controlled from a single control point, (before HSPA it was on the same channel) therefore the voice and data can flow effectively in parallel. I won’t go deeper but this is the end effect although there are some finer points.
  • 4G LTE based networks need to have Simultaneous Voice and LTE (SVLTE) capability on both network and devices to operate in parallel.  It’s a specific function that allows better control of the voice and data over the networks. 

Today’s 3G + LTE networks carry voice over 3G networks as circuit switched voice. In a circuit switched paradigm, voice is carried in a point to point stream and requires real time connection between the two points, much like 2 tin cans with string, or a wired phone. Voice over packet, such as voice over IP networks use a connectionless paradigm, no open line is required. The world is starting to prefer it because this method also allows the use of the time in between the sound pulses to carry other data. Skype is and example of voice over packet (sound is quantized and sent over packets on the internet.) 

So the next iPhone launch with Verizon (3GPP2 based) will require specific upgraded network functionality like enhanced High Rate Packet Data (eHRPD) to be deployed as well as a multitasking OS, and multiple connectivity chipsets to enable simultaneous use whereas ATT (3GPP based) will have an easier time and only require the UE capabilities.

As of right now, the Qualcomm MSM9600 chipsets appear to support the SVLTE functionality and based on their use in The New iPad it appears Apple is headed down this path so it will be up to Verizon and others to deploy the necessary network upgrades.

Hope this helps.

Interesting slides on VoLTE….

Download (PDF, Unknown)

Voice over LTE

LTE Benefits to the End User

Thought I would have some fun and go through the top 5 reasons the average consumer should adopt LTE. The point was to verify there were some end user benefits vs operators seeing all the benefits. I did my best to limit myself to today’s benefits, so there’s no HD Voice or global roaming etc in the list. See if you can think of better ones. Here are my top 5…Drum roll….

  1. Increased competition between carriers
  2. Supports ever growing Multi-mega pixel camera trend
  3. Safer to use at the sandwich shop than WiFi
  4. Low(est) mobile wireless latency
  5. Alternative to DSL at home
What? Here it is atom by atom.

1. Increased competition between carriers:  In the US, a less competitive wireless market, ATT, MetroPCS and Verizon already offer LTE, Clear, CSpire, Sprint, T Mobile, US Cellular are launching this year. I don’t like paying $25/GB/mo so I’m hoping the price competition will pressure down those prices. Yes supply and demand effects will have me using more and paying more, the low end is a mental barrier that needs to be crossed. Secondly, the increased competition with the identical services will result in greater focus in performance. The networks themselves will improve as a basis of competition further making end user experiences better.

 

2. Supports ever growing Multi-mega pixel camera trend: For this one , it’s bandwidth. Tip of the iceberg example, no way 3G is going support transporting your 17Mega pixel pictures of the puppy rolling over very quickly. LTE’s bandwidth will help out greatly here. Also, it looks like we are finally wanting to video call each other which is not very pleasant out on the road on 3G.

 

3. Safer to use at the sandwich shop than Wifi: Security of LTE vs WiFi is very deep and I won’t go into all of the nuances. Suffice it to say, at the lowest common denominator, it’s not free to begin stealing your data if on an LTE network. It takes significantly more effort than that. All that being said, I don’t want my instant messages to my wife on the internet. (yeah, ok, assume I have some end to end secure IM client.)

 

4. Low(set) mobile wireless latencyGaming. ‘Nuff said. Actually since the latency is so much lower than other wireless technologies, it’s going to make Push To X (PTx) services finally really usable. It also benefits chat and video calling a great deal. All of these apps are far more possible, pleasant etc on LTE than 3G or even WiFi under low loading in some cases.

 

 

 

 

 

 

 

 

5. Alternative to DSL at home:For this one  Tie it to your ‘stick it to the man’ strategy. Don’t know about you but it’s only recently I’ve had choices in wired networking. Another option never hurts when it comes to connectivity at home. More competition, and better pricing, better service as mentioned above.  

 US Cellular announced that they are rolling forward with their LTE deployments. Their networks are going live in areas in Iowa, Wisconsin, Maine, North Carolina, Texas and Oklahoma, and their key markets of Milwaukee, Madison and Racine, Wis.; Des Moines, Cedar Rapids and Davenport, Iowa; Portland and Bangor, Maine; and Greenville, N.C. In March and they noted that 

U.S. Cellular is the first wireless carrier to offer 4G LTE in several of these markets. Bravo!

 Naturally they are launching Android based Samsung tablet and a Samsung Smartphone.  

Most interestingly, they are launching within their lower 700Mhz so this would be a first mover in the band, potentially first of many. With their 3G in PCS and AWS, they can easily support Simultaneous Voice and LTE (SVLTE) using the lower 700MHz. Here is a map of their current spectrum holdings.

Read Full Article →

 Right under our noses, Samsung’s SCH-R930, a Galaxy device similar to the Samsung Indulge on MetroPCS’s network is launching as was parroted in the blogosphere. What I realized about this was the interesting thing is FCC testing shows that it’s an all band player, with AWS, PCS, Cellular and yes,

Lower 700MHz covered for 5MHz and 10MHz channels. US Cellular is slated to launch this device, as they Tweeted last week, in April.

BTW, the Huawei Honor they are launching does not support this band so to me this points to US Cellular launching LTE on AWS. On the other hand there are a lot of lower 700MHz spectrum owners who have a hole burning in their pocket right about now…Good luck and keep the lines orderly!

Notice Samsung is very understated on this device. Hmmm…

 

Links: FCC, Engadget

Read Full Article →

Friday US Cellular (USCC), a regional operator in 26 US states with around 6M subscribers, announced their intention to launch LTE by the end of the year.

This is the culmination of over a year of trials with multiple vendors in various configurations. Overall, I am impressed by their thoroughness in their preparations. Verizon, MetroPCS, Cellular South, etc…have been launching this technology for a while, but US Cellular went through the analysis and testing all the way through, from multiple RAN vendors to EPC and IMS options. To me, that’s good decision making. It should be no surprise then that USCC also happens to be a spectrum rich operator. See the overview charts:

As you can see, they are able to deploy 5MHz and in some cases 10MHz channels with new spectrums, and perhaps eventually refarm their 850/PCS spectrum that carries 1X and EVDO today. More after the break.

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