The affair about wirelessly pullulate video to millions and millions of phone is that it ’s , like , hard .
Wireless vs. Wired
Why is it , you might be wonder , that wireless speeds ca n’t just zoom zoom , faster quicker , the manner that Verizon or Comcast seem to press a button and magically , new , faster internet speeds seem . Well , for one , it ’s not that magical — even cable and roughage oculus “ wired ” broadband cost billions of buck per year for new internet pipe , with plenty of griping from carrier about TV and soaker and other bandwidth hoggery , hence all the bombination aboutnet disinterest .
But there are more demanding restraint when it comes to wireless broadband :
• Speed : No matter what happens , wired engineering science will be faster than wireless , because electric impulses steer upon a wire , or optical impulses running through fiber , are more efficient than radio waves scattering themselves into the atmosphere in the hope of getting picked up .
• dependableness : Even when you’re able to systematically pick up wireless signaling , its potency may variegate , not just because of how close you are to the cellular phone tower or Wi - Fi hotspot , but because radio is blocked by the leaf on the trees , or the water in an aquarium .
• price : present the same bandwidth wirelessly will always be more expensive , because radio waves — due to the above constraints — require monumental amounts of great power to work well . As we ’ll see , there ’s also a matter of paying for the right field to employ tuner wave , a perquisite that is only granted after payouts in the million of dollars .
If that vocalise a snatch remedial , it ’s supposed to : Wireless always , always lags behind wired . Think of how much faster gigabit ethernet is compared to Wireless N. It ’s just how the world works . But people need wireless connections , in their pockets , for obvious reasons . What we ’re speak about is why it ’s so hard to attract off well .
What’s Coming
See that chart up above ? That ’s the growth of data point traffic on AT&T ’s connection over the past four years . Despite all the e-mail , photo , music , tweets , apps and voice information traveling across the connection , the single largest character of dealings is video . Funny thing is , the true picture blowup has n’t happened yet .
What do I mean by that ? Well , take Netflix ’s check Instantly rain cats and dogs video service , for case . Right now , the only mobile equipment it ’s usable on is the iPad , with an iPhone app promised by the closing of the yr . But Netflix ’s vision is to be on fundamentally every gimmick with a screen . envisage a world where every phone , millions and 1000000 of them , can stream about any movie over the air . Where phones with bigger , good , high rhenium blind demand serious quality video to take reward of the extra pixels . Multiply that by apps current or future apps for Hulu , SlingPlayer , ABC , CBS , NBC , HBO , Vimeo , and oh yeah , YouTube .
Not to mention cyclosis video from phone , which are on the wand of universally breaching HD tone transcription . Today , Microsoft ’s Kin earpiece — turn tail on Verizon ’s 3 one thousand meshing — mechanically upload every 5- and 8 - megapixel photo , every 720p television you record , to the cloud . They ’re just the first , to be certain .
Two years from now , that stripe at the far right hand of the chart may appear as tiny as the one at the beginning , compared to the dealings that ’s coming .
There are three major constraints on streaming video recording to a wandering gadget over the melody : wireless spectrum , backhaul , and the gimmick itself .
Need More Spectrum, Dude
Wireless spectrum , while inconspicuous , is not an myriad resourcefulness . In fact , it ’s pretty damn constricted , at least in crowded urban sphere .
To radically simplify it , an easy way of life to think about spectrum is kind of like a main road , separate into lanes . In the US , the FCC designates who and what ’s permit to travel in each lane . ( Check out theFCC ’s spectrum dashboardto see who owns what spectrum where . ) The FCC typically divides the spectrum into “ block ” ( stick with the mixed metaphor here ) that are 10- or 20 - MHz all-embracing ( so a carrier would get , say , a slice from 700MHZ to 710MHz ) . A standard contour is for a carrier is to use half of each block to transport a signal , and one-half to receive ( outbound and inbound traffic ) . Each lane / blocking can only carry so much traffic . So when you get a short ton of people pumping a ton of stuff over the airwaves in a little area , you race into issue .
The result , though , is not just to build more jail cell towers for a given absolute frequency ad infinitum — it does n’t in reality produce more radio receiver spectrum in the universe for signal to locomote on , and in fact , if you crowd too many tugboat too close together , you get crew of noise and interference . fundamentally , you do n’t paint extra bloodline on a pike in decree to make way for more motorcar .
The best solution , from a carrier perspective , is to get more spectrum deal from the FCC . Typically the rights have to be purchase for billion of dollars , as you might ’ve noticed during the frenzied devouring of the 700MHz block by AT&T and Verizon for their upcoming 4 gigabyte LTE networks . The thing about 4 G is that is use really fat channels — really wide lane — which is why they can transfer information really fast .
As a side musical note , not all spectrum is the same : If you remember your high-pitched - schoolhouse physics , lower frequencies travel farther with less energy , and dawn buildings well too . As such , they are better suited for sharing massive amounts of wireless information , hence the popularity of the 700MHz block , for carriers who generally deal with spectrum from 1700MHz to 2100MHz .
No matter how many FCC auctions , limited spectrum availability for carrier dealing with a data tsunami is going to continue to be an issue — Clearwire saysa 120MHz - wide gash of contiguous spectrum is what ’s needed for legit mobile broadband . The wireless industry connection CTIA state the whole industry needs about 800MHz of spectrum totality , as fight to around 400MHz currently allotted . That ’s whypart of the FCC ’s national broadband planis to reallocate 300MHz more for roving broadband in the next five years .
Need More Backhaul, Dude
Next up is backhaul , which is fundamentally the connexion between cell tower and the rest of the connection . Even if a carrier had a virtually infinite amount of spectrum to impart all of that data point back and forth between phones and towers in a phantasy reality with special signal strength and no interference , they ’d still demand juicy pipe prevail from each and every cell tower .
Without decent backhaul , cell towers will campaign into the same kind of congestion problem you go into at household when you ’re stress to torrent more than your internet joining can handle . Everything slows down , and it fellate . The problem is that a vast portion of the jail cell tugboat in the country are still plug in using dull copper lines , and running fiber backhaul to them is expensive . ( No carrier will reveal how much of their backhaul is actually fiber for competitive reason . )
There is also the option of a wireless microwave backhaul , but it need cell towboat that are in the same line of mess , and at some percentage point the data still has to go telegraph .
The Phones, They Are Puny
The final constraint on delivering streaming video over the air ? The headphone themselves . sure enough , the flake inside of them may technically support wireless broadband speeds of 3.6 or 7.2Mbps , or even faster , but actual speed incline to be about one-half of their theoretic maximum , in part because run full blaze would kill their bombardment that much quicker . And remember those phones with the antenna you had to yank out ? Tech may have gotten adept , but those antennas went aside for mostly cosmetic rationality — we’d be honorable off with big old metal sceptre sticking up out of our Droids and iPhones .
Let’s Talk About the Video
Okay , so let ’s verbalise a spot about the genuine video recording , and the ways it make it to you . As it reverse out , there are in reality special standard in shoes for mobile video that are a spot different from the more familiar standards for the universal net , since they ’re designed specifically for headphone . But , with phones getting right and better at handling the literal web — since they ’re just very personal computer — a break is pass , so that roving standards are more like the genuine net .
Some of the most standard , um , standards are define by the 3GPP and 3GPP2 — the 3rd Generation Partnership Project(roughly , GSM material , so in the USA , T - Mobile and AT&T ) and3rd Generation Partnership Project 2(roughly , CDMA hooey , interest Verizon and Sprint)—which lays out standards and specifications for telecommunications things , include peregrine phone multimedia system . In fact , they even have qualify container format for audio recording and video ( the data file candy coatings around the codec centre , like h.264 or MPEG-4 or MP3 ) called 3GP ( fix by the 3GPP for GSM speech sound ) and 3G2 ( project by the 3GPP2 for CDMA phones ) that most 3 G phones can play .
More importantly , though , is the 3GPP ’s specification for apacket - swap streaming help — explained in majuscule detail here(PDF)—and its protocols like Real Time Streaming Protocol and the Real Time Transfer Protocol ( RTSP and RTP ) , which delineate one of the major frameworks used to stream TV to mobile phones . The independent thing to know about is that they ’re plan to be global standard , and they ’re built to adapt to wildly varying internet conditions , adjusting bitrates on the fly . And if a flattop or divine service is serving 3GPP video to mobile earpiece , they need special servers to do it .
But because of wirelessly connect netbooks and devices like the iPad , more and more telecasting comes over mobile networks in the form of good ol’ HTTP . The hyper - text carry-over communications protocol — the basis of all vane browsers — comes in two ecumenical smell . There ’s non - adaptative HTTP streaming , which is incredibly simple , just a current pumped out at a given bitrate , no matter what the net conditions . hassle is , it ’s so simple , you ’re apt to see plenty of stutters and freeze - ups if your web connection on the spur of the moment go to the south .
HTTP adaptive streaming is what it sounds like , a smart take on HTTP streaming that it accommodate in real sentence to meshing conditions , switching to different bitrates depending on what the current bandwidth situation is like . It does n’t require a special waiter , either . It ’s actually what Apple expend as its standard for streaming video over - the - atmosphere to the iPhone and iPad . ( Theycall it HTTP survive streaming . ) Microsoft has its own spin , calledsmooth streaming .
A quick news on codecs . Just like much of the internet has anointed h.264 as the standard for cyberspace video recording , so go mobile video . Verizon and SlingPlayer , for instance , both currently apply WMV for their streams , but without promise anything , Verizon says “ h.264 seem like it ’s got a lot of promise , ” while Sling suppose they ’re definitely moving to h.264 ( as they already have on the iPhone ) , since it ’s a “ tight codec ” that ’ll help them expend a little bit less bandwidth and support ironware accelerated decipher . Of naturally , Apple ’s HTTP endure pour only supports h.264 , so if you use an app that pour video over 3 guanine , it ’s coming via HTTP live streaming , and it ’s encode in h.264 .
( In compositor’s case you were curious , most of the 3GPP video is encode in h.263 MPEG-4 , with AMR sound recording , but it ’s bit by bit shift to h.264 , too . )
An Alternative Approach to Streaming
So , there are two broad access to get television to you — unicasting and multicasting . Unicasting is what I mostly described above , and what you ’re probably most familiar with , actually . When you attend at a YouTube picture , pull up a Netflix stream , watch a video on a site , or any kind of stock internet video , it ’s probably unicast — it ’s blend to you on need , from get-go to finishing . Multicast , on the other deal , is basically broadcasting — it ’s being pumped out there continuously for any number of people to pluck up . It works best for alive result , like news or sports , but if you do n’t jump in at the start of an event , you ’ll pretermit something .
The most prolific of the multicasters in the US is Qualcomm ’s MediaFLO , which subsist as a freestanding service , and is offer through Verizon ’s VCAST and AT&T ’s Mobile TV . It expect specific phones with MediaFLO - support , since they involve the MediaFLO receiver and decoder chipset . The canonical current , if you will , is that Qualcomm takes mental object from a broadcaster , sends it out to its own national internet of broadcast tower , and phones can tune in — just like program television set , but beamed using the FLO communications protocol .
The reward of multicasting is that it ’s super scalable : For gaga alive events — say , the Super Bowl or World Cup — it ’s no more demanding to do video to a million phones than it is to ten thousand phones . And since MediaFLO apply Qualcomm ’s own apparatus , it takes strain off of the main cell electronic web for the carrier . That ’s why Qualcomm sees MediaFLO as complemental to the grow availability of streaming on - demand cyberspace TV .
The Current State of Video
What kind of video are we actually getting today , anyway ? Does it actually calculate comme il faut ? Well , here ’s a brief assessment .
Verizon ’s VCAST service adapts to the equipment — meaning they have to encode a single video several time at varying quality levels — so at the top last , a phone like the HTC Incredible would get a flow at around 256kbps and 15fps and Verizon is explore live higher , up to 400kbps with 30fps . AT&T still prefers 3GPP video , since most of its telephone set support it , streamed at bitrates between 64 - 200kbps . Qualcomm ’s MediaFLO circularize a single flow of 320×240 stream . And Apple’sHTTP live streaming specsfor cellular phone networks — which every video stream app for iPhone and iPad has to use , from Netflix to Sling — race from 64kbps to 240kbps . All of them are a long , foresighted way from HD .
Netflix over 3 G is in reality impressively watchable today . But with 4 thou connection — LTE and WiMax — and raw equipment with faster , more energy effective processors , a near - future where we ’re all streaming near - HD video anywhere and everywhere is n’t so far away , if you squinch hard enough .
https://gizmodo.com/giz-explains-why-wimax-and-lte-wireless-4g-data-will-b-5168035
You know , unless we really do explode the internet .
Still something you wanna have sex ? Send questions about streaming video recording , sprinkling , or squirtinghere , with “ Giz Explains ” in the subject line .
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