Breaking News
News & Analysis

DIDO promises wireless breakthroughs

7/28/2011 03:06 PM EDT
51 comments
NO RATINGS
Page 1 / 2 Next >
More Related Links
View Comments: Newest First | Oldest First | Threaded View
Page 1 / 5   >   >>
cmpmoab
User Rank
Rookie
re: DIDO promises wireless breakthroughs
cmpmoab   2/26/2012 6:39:11 AM
NO RATINGS
I got the impression that DIDO was being designed for large-scale distribution. "It is important to note that DIDO was designed to be a mass-market product" If so, The data center infrastructure that will have to exist would be understated as MASSIVE. Additionally, If I'm reading the white paper correctly there will be a need to have end points to perform the actual transmissions. "having many distributed antennas" once again, MASSIVE deployment Ever been around something thats transmitting at the higher end wavelengths? "frequencies from 1 MHz to 1 GHz" the energy required for 100MHz and greater, not to mention the environmental implications = wow The math that would be involved, not just at the DataCenter level, but at the recipient level to achieve receipt, goes way beyond simple tower hopping. remember even a medium size city could contain ###xMillions of nodes and none of this takes into consideration the possibilities of advanced devices being commercially available in the next 3-5-7 years This may have small enterprise applications, but I cant see it as being a progressive solution. "Merger of cloud computing, cloud gaming and cloud wireless" Now "clouds" with VM's floating /drool I may get schooled as a result of this post, but it's the first impressions I got from reading the White paper, and some of the posts.

Tie L.
User Rank
Rookie
re: DIDO promises wireless breakthroughs
Tie L.   11/6/2011 8:24:07 AM
NO RATINGS
I think this DIDO technology is another variant of spatial diversity multiple access scheme. TDMA FDMA CDMA SDMA... I wonder what will be the next big thing in wireless technology in the coming 20 years?

Bert22306
User Rank
CEO
re: DIDO promises wireless breakthroughs
Bert22306   8/20/2011 10:47:20 PM
NO RATINGS
I like innovative ideas, but not hype. What's wrong with saying that this is MIMO, with a slight twist? That's what it is. You spread out the MIMO antennas, locating each closer to a user. A couple of other thoughts. No one is violating Shannon's law here, or in MIMO. Shannon's law applies completely. In MIMO or DIDO, you treat each propagation path like a separate channel. That's all. And you use clever filtering to make sure the channels stay separate. If the same-frequency channels were separated by large distances, no one would be BSing about violating Shannon's limits, right? This is exactly the same thing. The separation is not by distance, but by propagation path. So what? Furthermore, you certainly can achieve 10X multiples using MIMO. Search on 16X16 MIMO schemes, for example. It's been done and demonstrated in the field.

p_g
User Rank
Rookie
re: DIDO promises wireless breakthroughs
p_g   8/17/2011 7:09:51 PM
NO RATINGS
But I don't find his claim of 4% if there are 25 wireless access points to be valid. I do see at-least 15-20 access points when ever I try to connect to my AP, however I get close to 50% of speed almost all the time. Also in my opinion, he over simplified his idea while presenting about DIDO. I am also not RF expert, but I dont buy his concept can really go 10x or 1000x type ratio. Infact to me it sounds more like CDMA concept where it distribute its signal on 100x or 1000x bandwidth which is shared by almost all users. Using code multiplexing each signal can be uniquely reconstructed in presence of other signal which get filtered as noise. This allow same channel to be shared by many users simultaneously and speed get compromised but not linearly. And it also reaches limits again depends on various factor and not following any theoretical limits.

oursbud
User Rank
Rookie
re: DIDO promises wireless breakthroughs
oursbud   8/11/2011 2:32:01 PM
NO RATINGS
I have worked with wireless networks for the past 15 years, both in research and in startups. I just want to make a simple statement that may shed some some light on whether this can work and more importantly how novel this invention is. Then you make up your mind (mine is made): Go to DIDO website and downoad their whitepaper. The way you can eliminate interference in wireless channels is explained there: You take many potentially interfering WiFi access points (AP) (as many as you want , 10, 100) and you link them together with wires, so they become all connected to a shared node (DIDO calls it a central "data center"). Once these 10 or 100 AP antennas are connected, what you have effectively built is a single virtual transmitting device with 10 or 100 transmit antennas. Such a device is well known to the wireless industry as "Distributed Antenna System". Now send linear combinations of all the data streams expected by the 10 or 100 users to all the antennas, but carefully select the coefficient of the combinations such that a given data stream only reaches its intended user why not interfering with the other 9 or 99 users. Simple algebra using orthogonality principle will do the trick This process is well known to the wireless industry as "transmit beamforming". Once interference is gone, you can do the same process with as many users as you like, just link more AP together (this has a cost by the way). So none of the key components of the invention are new. Now you may say, but wait Distributed Antenna Systems are known , beamforming is known, but combining these two concepts must be novel. Problem: This precisely was proposed 5 years ago by Alcatel-Lucent under the name of NETWORK MIMO. Network MIMO (also called as "CoMP") is an advanced version of Multiuser MIMO and is currently being discussed for standardization for LTE cellular networks and beyond as a way to resolve interference in cellular networks.

mcsruff
User Rank
Rookie
re: DIDO promises wireless breakthroughs
mcsruff   8/5/2011 12:23:56 AM
NO RATINGS
As already said in a previous reply, DIDO is simply Multi-User MIMO by another name. Australia's CSIRO is the world leader in this and already demonstrated real-world wireless transmissions using this technology in early 2011 - see: http://www.csiro.au/files/files/pznm.pdf .

Ming T.
User Rank
Rookie
re: DIDO promises wireless breakthroughs
Ming T.   8/4/2011 7:07:17 PM
NO RATINGS
1) Obtaining CSI takes time and it scales up with number of stations and the change of environment (e.g. moving objects around the station which change the CSI). Also, while the channel estimations are required to be done in interference-free channels. Why? while the Channel is being estimated, AP doesn't know the station's CSI. Hence, AP or cloud has no information to do the linear algebra. So clean channel is needed. So, if there are people/ objects moving, sorry, DIDO also faces the same situations that traditional wireless tech is facing. \n 2) Cell edge effect. It's reasonable to assume that no AP can cover the whole Earth. There will be some areas that a AP can cover while the other AP cannot cover as they are placed in two locations. In this case, even though a station is in the coverage area that two APs are not overlapping, the DIDO concept still request two APs to work together to give the best signal to that station. Therefore, even though the DIDO system may just want to cover a small area, it still need to handle the interference coming from the areas that are out of its intended coverage. The complexity in the cloud server is extremely high then. Think of how many users AT&T has, say 2 millions. So if DIDO want to replace AT&T, they need to do a 2M x 2M matrix inversion every mini second. Not to mention, you need to silence other 2M-1 users when your channel is being estimated as I discussed in point 1. \n

Ming T.
User Rank
Rookie
re: DIDO promises wireless breakthroughs
Ming T.   8/4/2011 7:01:39 PM
NO RATINGS
Basically, DIDO is exactly the same as distributed multiuser MIMO (MU-MIMO). In centralized MU-MIMO, a AP (base station) has M antennas, and there are M stations, each of them has only 1 antenna. The AP requests channel estimation on each station so that it can obtain all Channel State Information(CSI) of all its M antennas to that station. Once the AP has all M-by-M CSI, by simple linear algebra (matrix inversion), AP can pre-filter the signals so that each user can receive signal with free of interference from others. In the distributed version (DIDO), the only difference is that now we have M APs and each one has only 1 antenna. Basically, M APs are cooperated so that they work like centralized MU-User. The cooperation is achieve by asking all the APs sending the CSI to the centralized server (cloud). Then the cloud will do the linear algebra and request the APs to send appropriate waveform to out to the air. The DIDO idea definitely works. But there are at least two caveats (discussed in my next comments):

kartik_subbarao
User Rank
Rookie
re: DIDO promises wireless breakthroughs
kartik_subbarao   8/4/2011 5:14:06 PM
NO RATINGS
When I refreshed the page, it fixed the formatting. Go figure :-)

kartik_subbarao
User Rank
Rookie
re: DIDO promises wireless breakthroughs
kartik_subbarao   8/4/2011 5:11:12 PM
NO RATINGS
Looks like it didn't recognize the blank lines between paragraphs :(

Page 1 / 5   >   >>
Flash Poll
Radio
LATEST ARCHIVED BROADCAST
EE Times editor Junko Yoshida grills two executives --Rick Walker, senior product marketing manager for IoT and home automation for CSR, and Jim Reich, CTO and co-founder at Palatehome.
Like Us on Facebook

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
EE Times on Twitter
EE Times Twitter Feed