* Posts by bminish

10 posts • joined 27 Dec 2009

Big barrier to 5G cracked by full-duplex chippery


Difficult to do at power

This will be difficult to do at the higher powers needed an a real world environment since a proportion of the transmit signal will be reflected back from the nearby environment. In the Real world this means things like walls, the ground etc.

Nonetheless this is an impressive achievement that may help us edge yet closer to the Shannon Theorem Limits

Pond, rocks or quicksand in your 1km garden? Get a rugged DECT phone


DECT + Mobile

Why can't I have a Mobile that also has DECT support that I can register to our DECT system(S) It would be much kinder on battery and more reliable than SIP over Wifi

If 4G isn’t working, why stick to the same approach for 5G?


Pesky Claude Shannon

We are very close to the Shannon theorem theoretical limits in terms of spectrum efficiency, From here (LTE) significant gains in terms of throughput for a given amount of spectrum can only come from making cell sizes much smaller for better frequency reuse.

This would also allow under some circumstances for less attractive but less congested spectrum above 3.5Ghz to be used, where block sizes tend to be bigger too so making more spectrum available ( but far less desirable in terms of coverage.). This is further complicated by trying to fit global standards in around national spectrum availability, this is already a real headache for LTE globally.

Small cells only make sense where there's enough profitable usage to justify the costs of building and maintaining a much denser site deployment.

As long as operators can continue to meter for usage then the easy and familiar lever will be volume based pricing combined with the minimum density required to deliver basic coverage. Get the headline speeds up but ration usage, it's the option that will best satisfy the shareholders.

Not a pretty future..

US boffins demo 'twisted radio' mux


I fail to see how this is any different from using Horizontal and Vertical Polarization. H/V if carefully set up allows for 2 separate paths with good Isolation. This is Widely used today

Brit balloon bod Bodnar overflies North Pole


Wizard Anorak engineering by the builder. I was able to hear and track it out to 274Km. The builder did a great job with the Radio engineering.

As an added bonus, at this stage it looks like there are good odds on it overflying the original launch site too.



It got within 12Km of my House and as a fully licensed anorak I was able to track it on packet radio, Still hearing it although it's now about 50km away

Google Fiber says it's happy to let Netflix onto its 'fast lane' for free


North america seems to lack neutral peering exchanges.

We ISP's in Europe are able to connect directly to the content networks and other ISP's at the nearest neutral peering exchange. Peering exchange members pay port charges based on the size of the port they require, not a charge based on traffic balance.

In terms of our company ( an ISP) this means we get ~70% of our peak customer traffic delivered directly to us from content providers across neutral peering at INEX.

This is a model that makes sense when you consider traffic flows between ISP's and content providers. But it's hard to deploy in existing markets that have evolved without the concept of neutral peering and it 'may' deprive Tier one transit providers of revenue by creating more direct connections between content and consumers.

Now we know why UK spooks simply shrugged at SSL encryption


With traffic analysis on a grand scale it simplifies the matter of deciding what to decrypt later.

The charge of the alternative gadget chargers


WiFi Charger is snakeoil

The power density of the microwave E/M radiation (Wifi etc) in any place (bar the insides of a microwave oven..) will be several orders of magnitude less than that available for harvesting in the visible part of the E/M spectrum.

In simple terms power densities at microwave frequencies from Wifi 3G etc will be very very small indeed, thousandths of a mW per M2 .

Optical radiation on the other hand (Light ) will be of the order of 10's to hundreds of W per square meter. Even comparing the amount of energy to light up a room with the amount of energy required to run a Wireless access point (which typically radiate 30mW or less) should indicate that this 'WiFi charger' is nothing more than snake oil since at best it could only manage to harvest thousands of times less energy from it's surrounding environment than the equivalent sized solar panel would manage

If it sounds too good to be true then it probably is..

Devolo dLan AVplus

Thumb Down

OFCOM & Enforcement

Actually they can. Just because a device has passed test does not mean that it is complaint with the EMC regulations when actually deployed.

A device can be fully complaint with the relevant EMC standards ( & these Powerline device are fare from compliant) yet not comply with the EMC directive when operated. one of the essential requirements of the directive is

"the electromagnetic disturbance generated does not exceed the level above which radio and telecommunications equipment or other equipment cannot operate as intended"

Enforcement where devices are preventing radio services operating as intended is the responsibility of national regulators, in the UK's case, OFCOM

EMC directive is readable in full here.



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