Currently viewing the tag: "Qualcomm"

84kb cropped version The Small Cell Americas Conference and Small Cell Forum events are taking place this week in Dallas, Texas. This makes me think back in time….smallcellsamerica I first started discussing small cells as a product in 2002, at Samsung, and 11 years later we have progressed very little in the way technology normally goes. From what I can say, there have been 3 major hurdles that have not helped here. 

1. Big iron OEMs make lots of $ from macro cells. They have not seen a business plan that makes sense to them, you know where they introduce a product that essentially cannibalizes their existing revenue stream and converts $40K units into $400 units.

2. The operators are not exactly sure what to do here. Firstly, they have a business model that is pretty tight. They price a flashy new user device at an attractive price (normally break even or lossy), then subsidize this purchase with the anticipated 2 year service revenue. Notice there was no cell in the spreadsheet that was for small cell in that revenue plan. I’ve witnessed arguments between company executives over whom would actually ‘pay’ for the device, example, is it a marketing expense or is it an operations expense? Let’s call this one chicken and egg.

The egg: chickenegg1

They ask themselves, what will the consumer think of us, or another way, does sending a consumer a small cell signal to the public that our coverage is poor (even if it really is, and forget that it’s cheaper to operate a good network than a poor one)?

Here is an example of the back of napkin numbers that US wireless guys go through in this argument….

Per New subscriber: (So operators outside of the US have a similar calculation, but with smaller numbers- US customers are just gouged that way and, no, Called Party Pays is not the difference.)

  1. New device cost: -$899
  2. Customer Paid: $200
  3. Lifetime Service Revenue: (ARPU X 24) ($109.67x 24 = $2632.08)
  4. Small Cell Cost:$599
  5. Total Adjusted Revenue: $2033.08

Then they say something like, “Now you can plainly see we can’t afford this device at this price” and you are supposed to agree.

Naturally, the chicken would be:

…a small cell to ensure this coverage is perfect at that spot. Don’t forget, the OEM’s are not exactly cheering on the operator’s executives to figure this one out either. Count on these OEMs to throw anything that is really smoky on this campfire pow wow.

3. Exactly what is the business plan for the small cell manufacturer? Before chipsets came to the rescue, they needed to spend many millions on R&D to create a small cell, all very hard to justify at really low unit prices without large commitments in volume. Compounding the problem here: operators not promising small cell unit volume based on challenges above. This situation marginally improved when Qualcomm, Ubiquisys, MindSpeed+picochip, TI etc came with that piece but there are still large investments to make to bring one to market. R77_Small_Cells_T1

So, making a low cost device is not without market promise of volume. Unfortunately, there have been very limited distributions of small cells from operators and the numbers aren’t there.  I won’t talk about the other costs (based on complexity) of integrating the SIP based femto core into the networks- that’s a fiasco story for another day.

There are other hurdles but they are minor in comparison. Anyway, for all the promise of small cells, the only definitive thing that’s happened is WiFi is everywhere. You know, THAT, Wifi, that the carriers haven’t been able to monetize… It’s getting depressing- ugh, I’ll stop here…but as you know the story continues…We can finish this chat later….

Oh yeah- here’s a cool presentation from today’s conference….


The unprecedented growth in mobile data consumption, driven by smart phones and other data intensive devices, highlights the need for improved coverage and increased data throughput for subscribers. More than 70% of mobile voice and data traffic is generated indoors (Informa 2008). Unfortunately, macro base stations are located outdoors. Providing coverage from the “outside in” can result in a poor end user experience. In a macro network, user experience can be affected by several factors:

  • Cell size
  • Users distance from the cell tower
  • Backhaul
  • Number of users
  • Traffic levels

Femtocells allow operators to target capex where it is needed by bringing the network access point closer to the mobile user. This enables a higher data connection and an improved user experience. Qualcomm’s femtocell platform helps mobile operators stay competitive and respond to emerging technologies, while increasing coverage and the overall mobile network capacity with greater spectrum reuse for the operator. The Qualcomm platform will provide a flexible, fully integrated System on Chip (SoC) that allows equipment manufacturers and operators to deliver a best-in-class solution with the highest levels of integration and performance.

Increased interference is a concern when operators consider dense femtocell deployments to improve performance. Qualcomm has completed extensive performance analysis, simulations and field tests and developed innovative techniques to address the issue of interference management. These techniques and algorithms will ensure that the femtocell platform delivers a reliable user experience as a mobile phone moves from femtocell to macrocell.

Qualcomm is an active member of the Femto Forum and a key contributor to the Femto Forum white paper, Interference Management in UMTS Femtocells. As a result of research associated with this paper as well as extensive simulation and analysis done independently, Qualcomm has determined four key areas to successful interference management.



OK, this is the third update thanks to the upcoming Mobile World Congress (MWC.) Altair made their PR about their updated part last night after this list went public so I have added Altair’s latest processor to the matrix. 
Samsung CMC221

**Updated with GCT Semi, Renesys**

 OK, I’ve been industrious lately.I needed some information to improve a model that used LTE devices. I  was able to use the left overs and put them into a table here and did my part for recycling. Here’s the data, hopefully you can find some use for it.

Anyway, I remember reading lately in various blogs and news outlets that Qualcomm is about to get pressed as far as competition and they had better look out.

You can see from this chart that (A) the competition is already here and (B) they are still ahead. It looks like Qualcomm took the CDMA 1X dilemma and made lemonade.

Probably the best 4G per specifications seems to be Altair and Sequans seem to be slightly ahead of everyone else, attributable to their SDR architecture. They both have interference cancellation techniques which will become required for all future vendors to keep up. Broadcom, Marvell and Renesys are fairly close in published standards and seem to be only 1 generation behind Qualcomm.sqn3120

Another curious thing popped out at me, Apple is nearly alone at the top with a multi-chip solution. The SoCs are winning lots of marketshare. The partial exception is the Samsung Galaxy S3, which requires a 2nd chip for CDMA 1x, but that is rumored to be fixed in the next version. 

One other anomaly, Cavium purchased Wavesat with Odyssey and so far looks to be doing nothing with their $10M USD investment.




Column guide:

  • 3GPP Release = Supported features from the latest LTE 3GPP Release (Ex; Carrier aggregation support is in Release 10)
  • 3G = 3G on board or off board. 3GPP = HSPA/WCDMA and 3GPP2 = 1XCDMA/EVDO
  • UE Category (See table at left.) A category 4 UE is capable of 150Mbps.


Full table after the Next…


cell density increasing So here we are again, another insanely busy week of reviews, document development, product development etc… I did manage to sneak some time to check out these presentations on small cells. If you are new to small cells or not fully engaged 100% of the time with this area, I think these 2 presentations together are quite good. My friend Zahid Ghadialy posted the first one from Airspan presented to the Small Cell SIG titled “Non-Line-of-Sight Wireless Backhaul for LTE Picocell/Metrocell Deployments.”  

The story opens with a description of the small cell concepts and features that pertain to LTE. The plot thickens with deployment and backhaul requirements with a surprise ending. I do think the backhaul + small cell approach is a pretty good one.

Check it out.

Next I am pulling out an older one from Qualcomm (December 2012.) This presentation is titled “1000x: Higher Efficiency.”  It gives a great overview of the types of things driving small cell interest and Qualcomm’s view on how to use them. 

I will add these to the small cell section.
This is a very interesting area of the market and I believe it will be the primary focus of network expansion/deployments within 3 years.

iPad LTE pic I have written about my ire with Apple regarding their design decisionsThe basic complaint I have with the OEMs (Apple, Samsung, etc…) is that their LTE product design forces the end user to purchase a network specific mobile device. For example, I purchase a Band 13 device (VZW), I cannot then change my mind and go to ATT (Band 17) etc… Of course network operators don’t prefer this capability but let’s ignore that for the moment. Technologically, the ability to do this was limited by (A) the requirements of the devices and (B) the capability of the components in the devices.

Requirements as drivers to network locked devices.

Today’s mobile networks topologically, in the US from a data perspective,  are LTE overlays on existing 2G and 3G network coverage. This is a deployment scenario caused by the reality of the economy, risk aversion of operators etc and whatever. The requirement/expectation is end user  device is usable throughout the entire network coverage area of the network’s operator. Thus, if the LTE coverage ends, the device must gracefully hand down/over to 3G and resume data communications. This means a 3G radio and 4G radio is required to interact with the 2 networks (3G/4G.) 

Currently voice is carried over 3G and not VoLTE yet so this sets up more of the same 3G/4G multi-radio requirements.

Summary: Pure LTE device like a smartphone that uses something like VoLTE  for voice requires one radio and path at a time, today’s voice enabled devices require 2 radio paths. Data only devices can utilize a single radio path but are still hamstrung by the spectrum used for EVDO/HSPA as a fallback to LTE coverage holes ultimately requiring dual radio performance for smooth transitions. Oh yeah, CDMA EVDO handovers are better with eHRPD blah blah but I’m assuming a perfectly state of the art, fully capable device and network.

Capability of components

ipad3 teardown picI have written about the iPad radio design, and the key take aways were the RF chain required Apple to include band specific components to facilitate the multiple radio and/or paths required. There have been some improvements since I’ve moaned and I will go through some of those.


Firstly, let’s look at the antenna. If your load (includes antenna) is RF mismatched in the circuit with the amplifiers, duplexers, filters etc…the efficiency of the radio transmission/reception could suffer a great deal. This means more energy required to transmit/receive, possible harmful interference control measures required and end users end up paying more for poor performance in the end. I mention this because the previous crop of device antennae were not well suited for wide band use, like 700MHz through AWS 2100MHz in the same elements. 

Skycross,Skycross Logo a Fremont, CA company has recently announced some technology that can be helpful here. Here is information from their site:

SkyCross’ three core technologies contribute to addressing the growing number of frequency bands required for LTE and carrier aggregation.

  • iMAT allows a single antenna to act like multiple antennas through the use of multiple feedpoints. Each feedpoint accesses the single antenna as if it were two or more independent antennas, highly isolated from each other. This enables very efficient and compact antenna designs. Developers can combine the iMAT design with other antenna requirements to form a multi-band, multi-protocol antenna module.
  • VersiTune provides an advanced tunable antenna solution for multi-band 4G LTE devices in a single antenna structure. SkyCross can therefore actively tune an antenna from frequency band to frequency band accurately so that the antenna meets the many needs of a single operator or the frequency band requirements of multiple operators simultaneously.
  • MatchTune enables a single antenna structure to uniquely fine tune within a given LTE frequency band, which both enhances performance for a given frequency or for multiple simultaneous frequencies when employing carrier aggregation.

These technologies also enable ODMs and OEMs to improve the performance of their mobile devices, while concurrently reducing costs and shrinking the form factor of their products.

Here’s a good paper about their Isolated Mode Antennas (iMat).

So, yesterday’s devices required either poor efficiency or multiple antennas to support multiple air technologies and bands and now there is Skycross technologies that address these issues. OEMs can design true MIMO devices with good efficiency, in a reasonably small package. I think Apple at some point mentioned this problem with respect to their support for SVLTE in the Verizon version of their devices. Check this off the list of problems.

The next item on the list is the transceiver. I have mentioned Qualcomm’s WTR1605 previously, and this part essentially offers an expansion of bands and radio technologies over previous generations such that a typical 3G/4G band scenario that requires support for Bands 1,4, 12,13, 17 and 25 for LTE and PCS/AWS/800MHz cellular for CDMA. Furthermore, simultaneous support for 11 RX ports and 9 TX ports allow simultaneous multiple radio paths with dedicated PA/LNAs.

AnandTech went into some detail on the WTR1605L for your purchasing or RF hardware engineering pleasure in their blog: The State of Qualcomm’s Modems – WTR1605 and MDM9x25 (Actually, I liked the detail since Qualcomm didn’t publish any.)

WTR1605L RFIC by QualcommQualcomm says:

The WTR1605 will be Qualcomm’s first Radio Transceiver in Wafer Level Package and will be a highly integrated radio transceiver with multi-mode (LTE FDD, LTE TDD, CDMA, WCDMA, TD-SCDMA, GSM) and multi-band support. The WTR1605 will be optimized for low power consumption and small footprint and will integrate a high performance GPS core with GLONASS support. Samples of the MDM9615, MDM8215, WTR1605 and PM8018 are anticipated to be available in late 2011.

Lastly, the 3G/4G MODEM (baseband) is solved with Qualcomm’s 9200/9215 and 9600/9615/9625 parts support GSM/EDGE/WCDMA/CDMA/EVDO/and LTE the technologies of interest here. So we are nearly there with 3 parts. There is something missing though.

The Missing Link

the missing link image

So what’s stopping us from a single multimode multi-band design to serve all networks and end users? The Power Amplifier (PA) and Low Noise Amplifier (LNA) situation. I’m not going to go too deep here because for multiple reasons but on the face of it there are many extra components that would be needed to support all of the Bands 1,4, 12,13, 17 and 25 with MIMO for LTE and PCS/AWS/800MHz cellular for CDMA. It’s not impossible and there are some design decisions that can be made if the OEM is willing to live with extra band specific LNA/PA’s on board. The downside is without any magic, they will take up extra space, create more heat and consume power with or without use. I think there is a better way (Custom silicon) that Apple and Samsung could probably bring to bear more quickly than any other OEMs.  

There You Go

So as you can see, there are 2 paths and on 1, we are tantalizingly close to having universal mobile devices. Oh yeah, as I have mentioned before you will probably need a removable UICC too and Apple has this design presently.  The Path 1 fix with a universal mobile device, when to expect the LNA/PA/duplexor/filter solution? Like I said, an innovator like Apple or Samsung could knock it out rapidly (assuming quickly with core purchased IP from SkyWorks, TriQuint etc…) like mid this year. Else, the groundhog will see it’s shadow and we’ll be having to check at the end of next winter. On the Path 2 fix, implement VoLTE, make LTE ubiquitous and stop using 3G networks, that will take a wee bit longer.



Welcome to Las Vegas CES Been awfully busy this year and end of last so I’m wayyy off my desired schedule. The Consumer Electronics Show (CES) is quite the boondoggle and this year was no exception. There were a couple of things that were noteworthy to me with respect to the mobile industry and 4G that I would like to share with you.

Firstly, Qualcomm’s keynote. Usually Microsoft handles such things but this year Microsoft minimized their CES profile by not having a big booth etc… This is not really surprising to me as it was to some as they are exactly duplicating any/everything Apple does w.r.t. mobile.  Anyway Qualcomm tried the shock and awe approach to keynotes and added a bunch of colorful characters into the talk like Desmond Tutu, Big Bird, Steve Balmer, Guillermo Del Toro, Star Trek’s Alice Eve etc… Bottom line is they are going to continue to work hard to be the epicenter of wireless.

They unveiled their Snapdragon 800 mobile processor which supports everything including Ultra HD and it’s expected we will see that in next versions of mobile devices. Qualcomm also discussed their wireless charging (Inductive Power Transfer) technology a little, the brand they are selling is Halo and they are focused on getting it into vehicles initially. Wireless charging is the next logical step for all electronic devices so this makes a lot of sense. I will also mention they mentioned, with Big Bird’s help, their version of augmented reality. This is another technology I expect to be ubiquitous this year.

Cracks me up that after years of trying to talk them into small cells, they are suddenly the center of the small cell universe too. Better late than never. Ok I digress…Video of Qualcomm’s keynote highlights to your left. 

Following the keynote there were the strictly routine level of show floor booths, demo days, meetings in conference booths on/off the show floor, night out etc… This is a CES so the main focus is mainly non-mobile, and there was a lot of buzz around the forthcoming UltraHD (4K) TV’s and the always heralded but never sold in stores OLED versions of TVs. OK, 4K/OLED is cool and the only tie to mobile is you can expect these technologies on the 4th screen (mobile device.) 

Almost forgot, Samsung demoed their “Youm” bendable display. It doesn’t have anything to do with 4G but you could see one on a Samsung G4 or Galaxy 5.


There was an interesting group of demos around wireless power charging. Yes what’s old is what’s new. There are many companies in the developing ecosystem and I won’t really go into each one but they are aligning into alliances or industry trade groups.This is the same technology battle that happens when standards compete, so Rocky-Balboa-movie-20for example, with Betamax v VHS, Firewire v USB, CDMA v GSM or LTE v WiMAX, there will be winners and losers and the loser may have the superior technology, or not. So one approach was QI by the Wireless Power Consortium Wireless Power Consortiumrepresenting 100 companies, and by 130 announced products so far. They claim all QI certified devices are going to be interoperable (wireless charging wise.) Their technology is wireless but immobile, based on induction through charging pads etc…

 The second is the 25ish member Alliance for Wireless Power. A4WP Logo The big differentiator here is they allow more flexibility in how close/far the charging devices may be placed up to 50mm from the charger. (wireless, not quite mobile) What this group lacks in numbers they make up for in strength of their supporters.

Lastly, the third major exhibitor was the 30ish member strong Power Matters Alliance.Power Matters Alliance The technology differentiation is less clear to me, a wireless charging surface based approach but I guess their focus here is integration into public places. Yes, Starbucks is a member. 

Oh yeah, the waterproofing guys were back with a better process. I love little things like Liquipel! They offer a waterproofing coating for your mobile device that allows full submersion for a limited amount of time, like when your phone falls out of your front shirt pocket into a water fountain etc… (feel free to substitute your experience here.) Liquipel waterproof iphone


So all in all, the state of the art is inching forward. No major LTE Advanced announcements. 

Verizon @ CES

Oh wait, Verizon announced they are planning on launching an Evolved Multimedia Broadcast Multicast (eMBMS) service in the future. This was from the CEO Lowell McAdam. There were no specifics like timelines or what type of content but overall it makes sense to utilize their investment as much and as wisely as possible. 

Verizon has a site dedicated to eMBMS and they state they are working with Ericsson. 

Verizon Keynote here… 

OK, looking forward to this stuff now…

Real quick, AT&T execs are supposedly working to launch LTE Advanced next year!  I first saw this on TechSpot. Their Article is here:

AT&T executives confirm 4G LTE Advanced rollout will start next year

I think this is very plausible considering the standards will be in place at that time and they have this other spectrum that gives them some lower700MHz frequency space for one of the key features, Carrier Aggregation. Right now that spectrum is unpaired and unused and they paid billions for it so it makes sense to me.

  Oh yeah, 


Qualcomm is sampling their LTE-Advanced MODEM chipset the Qualcomm Gobi MDM9625/9225, now too. Hmmm...



 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

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. :)

 So there were tons of rumors swirling around the blogosphere and the actual media regarding the iPhone 5. Turns out, once again, the leaks from the 3rd party manufacturing companies revealed most of the hardware story correctly. On a side note, does anyone else find it weird that the leaks from Apple’s manufacturing chain make it to the press and others, say, Samsung who fancies themselves as an Apple does not get the benefits of this type of leaking? I also noticed that Sammy has hired some agencies to make/post unflattering comments…(searches show patterns) it’s so very childish…anyway…wait one more thing, I wonder if you could outsource/crowdsource negative blog posts to Amazon’s Mechanical Turk?  ok…

Here are my observations on the iPhone 5 LTE related design features.

 First: LTE inclusion in iPhone 5. 

Firstly, yes, it’s LTE enabled!

To me, the vast majority of ‘typical consumers’ will now begin to use LTE thanks to Apple’s marketshare and their inclusion of LTE in an easy to use package. 

As I mentioned previously, I do believe FaceTime video conferencing, as an application, will drive utilization of LTE bandwidth but it’s really only part of a bigger package of capabilities the iPhone brings to the market. And yes, not biased, Android will soon have all of these capabilities too.


I was looking at the iPhone 5 LTE availability and saw (from Apple’s site):

Model Number2

LTE Band Support3


Supported LTE Networks

Model A1428
(GSM model)


17 (700b MHz)

United StatesAT&TCanada

  • Bell (including Virgin)
  • Rogers (including Fido)
  • Telus (including Koodo)

Model A1429
(CDMA model)

(2100 MHz)

(1800 MHz)

(850 MHz)

13 (700c MHz)

25 (1900 MHz)

United States

  • Sprint
  • Verizon


Model A1429
(GSM model)

(2100 MHz)

(1800 MHz)

(850 MHz)

GermanyDeutsche TelekomUnited KingdomEverything Everywhere

  • Orange
  • T-Mobile


  • Optus (including Virgin)
  • Telstra


  • SK Telecom
  • KT

Hong KongSmarToneSingapore

  • M1
  • SingTel
  1. Data roaming depends on supported bands and carrier policies. LTE roaming may not be available. Contact your carrier for more details.
  2. To identify your iPhone 5 model number, see Unlocked iPhone 5 models may support LTE networks outside the country of purchase when using a valid SIM from a supported carrier. Contact your carrier for more details.
  3. LTE band support is based on the iPhone 5 model number and configuration for either CDMA or GSM networks. Band support does not guarantee support on all LTE networks running on the same bands.

Some features may not be available for all countries or all areas. Click here to see complete list.

Read Full Article →


I just wanted to add a link to Qualcomm’s latest HD Voice Video. It has some good description of the voice improvements going into their chipsets. This is probably a strong reason not to jump off their platform but there are other ways to create these same improvements.

HD Voice is starting to get some attention with the recent launches by Orange and Sprint. As the hypeometer’s needle climbs, there will be a lot of attention focused in this area. I just wanted to put a few facts out there to keep it all straight. These operators have actually different technologies behind their HD Voice launches that eventually merge at VoLTE. I saw some silliness about the HD Voice launches in AnandTech and other places so let’s get started…


First a brief history of the universe, starting with current voice technologies used with 3G networks.

Narrowband voice coding has been used in digital cellular systems since the beginning. Today’s smartphones typically employ EVRC for CDMA2000/3GPP2 based networks with a fraction of those employing the more advanced EVRC-B algorithm and AMR for UMTS/3GPP networks. EVRC and AMR are CODECs to transform voice into digitized speech using low amounts of bandwidth/throughput with a primary technique being limiting the input frequency ranges.

This chart shows the tradeoffs involved…

The measurement of voice is based on sampling a population of listeners that rate the quality of the spoken sentences after coding and decoding by an algorithm. Listeners are asked to (subjectively) rate the recordings they heard vs a reference standard. The reference standards are like (A) direct recording of voices or (B) Pulse Code Modulation (PCM) at 64Kbps known in standards as G.711. Here is an example of the rating questions:

This is an experiment to determine the perceived quality of speech over the telephone. You will be listening to a number of recorded speech samples, spoken by several different talkers, and you will be rating how good you think they sound.
Use the single headphone on the ear you normally use for the telephone. On each trial a two- sentence sample will be played. After you have listened to the sample, determine the category from the list below which best describes the overall quality of the sample. Press the numeric key on your keyboard corresponding to your rating for how good or bad that particular passage sounded.
Select the category which best describes the sample you just heard for purposes of everyday speech communication.
4 – GOOD
3 - FAIR
2 – POOR
1 – BAD

EVRC compresses each 20 milliseconds of (300-3200 Hz), 16-bit sampled speech input into output frames of one of three different sizes: full rate of 171 bits (8.55 kbit/s), half rate of 80 bits (4.0 kbit/s), eighth rate of 16 bits (0.8 kbit/s). EVRC has a peak bitrate of 8.5Kbps, a minimum of 0.8Kbps and ‘conversational’ planning rate of 6Kbps. 

3GPP2 EVRC Standards:  3GPP2 C.S0014-D

The AMR (Adaptive Multi-Rate) codec encodes narrowband (200-3400 Hz) signals for each 20 milliseconds of 8000 Hz at variable bit rates ranging from 4.75 to 12.2 kbps with toll quality speech starting at 7.4 kbps. AMR has a peak bitrate of 12.2Kbps, minimum of 4.75Kbps, ‘typical’ conversational rate of 4Kbps.

3GPP AMR Standard: TS 26.071

The goal of these narrowband VOCODERs is to reduce bandwidth during a conversation while delivering acceptable call quality. You will achieve near ideal speech quality but not full lifelike sound in perfect network conditions.

If you are reading this then likely you have first hand experience with the voice coders used in 3G networks. Moving forward …

Qualcomm (the main commercial influence for EVRC) has developed a more advanced (newer) line of CODECs they call 4GV which include EVRC-B and EVRC-WB (wide band.) Alternatively, there is a small consortium of companies that drive patents for AMR including Voice Age, Nokia, Ericsson, and France Telecom, and they have evolved their narrowband AMR with AMR-WB (you guessed it, wide band.) Lastly, there is SiLK, propelled by Skype. 





EVRC-WB is based on a split band coding paradigm in which two different coding models are used for the signal by independently sampling the low frequency (LF) (0-4 KHz) and the high frequency (HF) (3.5-7 KHz) bands.

MOS: 3.24( Street Noise, 15 dB SNR  )

EVRC-WB white paper by Qualcomm      EVRC-WB test results from 3Gpp2 testing

3GPP2 EVRC-WB Standard C.S0014-D_v1.0_EVRC

AMR-WB provides improved speech quality due to a wider speech bandwidth of 50–7000 Hz.

  • Configuration A (Config-WB-Code 0): 6.6, 8.85, and 12.65 kbit/s (Mandatory multi-rate configuration)
  • Configuration B (Config-WB-Code 2): 6.6, 8.85, 12.65, and 15.85 kbit/s
  • Configuration C (Config-WB-Code 4): 6.6, 8.85, 12.65, and 23.85 kbit/s
MOS: 3.14 ( Office Noise, 15 dB SNR  )
3GPP AMR-WB Standard TS 26.204
AMR-WB Whitepaper by VoiceAge

Comparison of AMR-WB and EVRC-WB…

SILK negotiates one of four modes during call setup: Narrowband (NB): 8 kHz sampling rate o Mediumband (MB): 8 or 12 kHz sampling rate. Wideband (WB): 8, 12 or 16 kHz sampling rate. Super Wideband (SWB): 8, 12, 16 or 24 kHz sampling rate. The purpose of these modes is to allow the decoder to limit the highest sampling rate used by the encoder.

MOS: 3.22 ( Office Noise, 15 dB SNR   )

Skype: Silk Data sheet and IETF Standard

Nokia paper comparing Silk and AMR-WB. (Note they are a patent holder for AMR-WB and the paper does slant that way.)

HD Voice is a broad term marketed by operators that seems to refer to the voice coding, more specifically the use of the wide band CODERs like AMR-WB and EVRC-WB. Therefore, under typical conditions, the additional bandwidth used will provide a more lifelike sound between the caller/called.

Operator Deployments

Orange in the U.K. began marketing HD Voice in September of 2010. They have a 3GPP based UMTS network thus they are using the AMR-WB vocoder. They have 7 handsets on their website as supporting the AMR-WB vocoder.

Sprint recently announced the launch of HD Voice with their launch of HTC EVO 4G LTE. Apparently they are using Transcoder Free Operation (TrFO) to support this feature. The basics of this are the 2 end points (Caller and Called) must have the EVRC-WB supported to be able to enjoy the additional sound quality. (It also means the network accepts Service Option 73 requests…)


3G phones have the VOCODERs built into the device and they only work with the connected 3G network infrastructure for voice calling. VoLTE uses an IP Multimedia System (IMS) architecture, that essentially is an application that runs over the LTE channel. The devices (UE) have an IMS client that uses Session Initiation Protocol (SIP) signaling to place calls. The IMS is functionally equivalent to their 3G counterparts but slightly more flexible as you can have various architectures such as distributed, localized, centralized etc… Some interesting flexibility exists in the IMS client, as it is possible for the IMS client to have variable VOCODERs and the IMS has a flexible architecture that will allow support for various VOCODERS. This probably means you can upgrade/downgrade to/from HD voice while mobile, and operators will likely support (free/incremental cost) wide band coding when on high rate connections such as WiFi, femotcells etc.. This makes life more interesting. 

On the flip side, the only official VOCODER supported with 3GPP for LTE networks right now is AMR. Some of you need to push SILK and EVRC-B into the 3GPP standards. Mobile calling could be so much more interesting than it is today.

OK, that was a huge wind up for a little paragraph. The point is HD Voice is available on a few operators over 3G today and likely available almost everywhere with VoLTE using mostly wide band VOCODERs that provide higher MOS scores but also use slightly more bandwidth than 3G voice calls. It will be interesting to see how OTT providers like Skype fit in as they can easily integrate into the IMS/3GPP/VoLTE architecture and may have more to offer in some cases.

 First ran across this story in After reading through the presentations and watching some of the video presentations, I was initially very skeptical. After thinking about it a while, it strikes me that this seems very sound approach even if the exact implementation for a commercial wireless networking infrastructure is different than what Dr. Amir Khandiani has outlined. So going a step further, I’m going to say this is a legitimate candidate for improving LTE and useful as a cornerstone to a 5G wireless. 

Firstly, there is a patent, Methods for spatial multiplexing of wireless two-way channels 7,817,641that covers most of the technology in this discussion.

From his presentation, the summary of the patent is: 

  • New methods for antenna design
  • New RF and base‐band processing brings degradation in SNR due to self‐interference close to zero.
  • Support for asynchronous clients (superimposed networking)
  • Support for MIMO
  • New applications for full‐duplex wireless
  • Hardware, RF and DSP complexities are virtually the same as half‐duplex units.
The technology is a layered approach that first utilizes a symmetrical antenna design including symmetrical pairings of multiple antennae to create nulls relative to TX and RX signals.

2D Symmetrical Antenna

MIMO Symmetrical Antennae

His presentation shows a null of around -15dB on a scope just for antenna nulls. This deserves a checkmark for simplicity.

The second layer of this technology involves active cancellation that is not-syncronized to the TX. He suggests if using a single TX chain, then just go to active interference cancellation. This is done today in multiple over the air technologies, comparable to Qualcomm’s QLIC etc… For multiple TX he suggests using ‘corrective’ beam forming. Beam forming allows a null (think of it as silence) to be created by the TX at the RX. He also suggests you can possibly have a mode where you use existing MIMO antenna and add an ‘auxiliary’ TX just for the purpose of interference nullling.

The last thing he shows in this layered approach is a final synchronous interference cancellation and equalization step in the base band. Performance example he gives is:

Residual Self Interference to Noise Ratio:

  • Antenna structure alone: about 40dB
  • After corrective beam‐forming: about 2dB
  • After base‐band subtraction: about 0.4dB 
So all in all this bit of technology is similar to, or can be thought of as, creating a electromagnetic set of ear muffs for the transmitter so the receiver can listen for distant signals at the same time the transmitter is singing. While there is nothing earth shattering about that as interference cancellation (IC) schemes are being employed on uplink and downlink in LTE today, it is important to note that this approach is a possible solution to the vexing self interference dilemma (If I shout, I can’t hear you at the same time…) with a repeatable, orderly system of layers. 
Lastly he mentions something I’ve been thinking of for some time, and that’s a shift from source based communications (unique signal stream including MIMO) The best way I can summarize it to be simple is, instead of using an isolated signal for transmission, focus on using the interference.

Media = The universe

Overall you can see the pieces of a wireless evolutionary step. I think the layered IC could be added after 3GPP Release 11 to further increase throughput/capacity and security of wireless transmissions. It’s very compelling if we shift to using mixed TDD/FDD modes and now you have the basis of a new range of applications including super low latency communications, extremely high security and so on. Throw in some cognitive radio and we are really capturing the lightning in a bottle. My hat is tipped to Dr. Amir K. Khandani, he found a good way to tie together different pieces of the puzzle to move the needle forward.

Links: E&CE Department, University of Waterloo, Qualcomm,,,

It may be very worthwhile attending his seminar 2PM on June 18th, 2012.

Dr. Amir K. Khandani
Department of Electrical and Computer Engineering, University of Waterloo

Shaping the Future of Wireless: Two-way Connectivity

Monday, June 18, 2012

2:00 pm

DC 1302

Their summary below.. 


Two-way (True Full-duplex) Connectivity: The Future of Wireless

Amir K. Khandani 
[email protected], 519-8851211×35324



Current wireless systems are one-way (similar to walkie-talkies), meaning that disjoint time or frequency segments are used to transmit and to receive. Realization of two-way wireless has challenged the research community for many years, generally believed to be impossible. This talk establishes the theory and presents practical realization of two-way wireless. In contrast to the widely accepted beliefs, it is shown that two-way wireless is not only possible, but is fairly simple, with virtually no degradation in signal-to-noise-ratio. More importantly, it is shown that two-way wireless can do much more than just doubling the rate. The innovation is in the antenna design and multiple levels for cancelling self-interference. Methods are developed to support multiple antenna (MIMO) two-way transmission, and asynchronous two-way links (useful in networking applications). These findings are expected to have a profound impact on wireless transmission, networking and security in the near future, more significant than other major breakthroughs in the last few decades.A number of new applications are introduced, showing that two-way wireless: (1) Facilitates wireless networking. (2) Enhances security through “desirable jamming”. (3) Provides the ground to realize unbreakable security (beyond computational or information theoretical security). (4) Enables a new method of wireless communications (to be introduced in this talk) based on embedding data in the transmission media by changing its RF properties in contrast to embedding data in the transmitted signal, and thereby significantly exceeding some of the known theoretical limits on channel capacity. (5) Enables realizing multi-node distributed & collaborative networking, which has been topics of extensive research in the context of Network Information Theory, but still far from practice. (6) Doubles the point-to-point throughput.

The developed hardware uses off-the-shelf components, antennas have a simple structure, are omnidirectional, do not suffer from bandwidth limitations, have a small size/spacing (comparable to current one-way systems), and the increase in signal processing complexity vs. one-way is virtually zero.

BIO: Amir K. Khandani is a professor of electrical and computer engineering at the University of Waterloo. He received his degrees from Tehran University, Iran, and McGill University, Canada, in 1984 and 1992, respectively. He joined uWaterloo in 1993. He currently holds the RIM-NSERC Industrial Research Chair on Network Information Theory and a Canada Research Chair (Tier I) on Wireless Systems. Prior to the RIM-NSERC Chair, he held an NSERC Industrial Research Chair funded by Nortel. He has supervised more than 40 PhD students, 30 master’s students, 30 post-doctoral fellows and 10 research engineers. His former team members have successful careers in industry and academia across the globe.



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