Posts by Andrew Somerville

They REPEAT don't collect any information

And you don't receive PlaceTips from the beacon.

A BLE beacon is a small box costing around £20. It is battery powered, typically with a life of 2 years between changes. As the name implies, it's a beacon - meaning all it does is periodically announce its existence using a unique ID. These announcements can be picked up any Bluetooth enabled device nearby. The beacon doesn't know anything about devices that have picked up their announcements and they are not Internet enabled so couldn't send any such information to Facebook anyway.

It is your phone that talks to Facebook's servers telling them it has detected a particular beacon ID. The server then checks this against a database of registered beacon IDs and hence knows where you are. Therefore for beacons to work with your phone they require (a) Bluetooth to be enabled and (b) the relevant app to be running (in foreground or background).

So if you don't want to be tracked, disable Bluetooth - but remember that every time you upgrade iOS, Apple sneakily turns it on again, or close down the Facebook app.

C.L.U.E.L.E.S.S Philip Dagnan

Seconds of googling allowed you to find a camera that (1) was not available when Westminster specified their system (2) has a sensitivity of 2 lux so is a fat lot of use for seeing at night. (3) cannot stream full rate video.

Designing CCTV systems may perhaps be a little more complex than you think.

Not a directional technology

As the Cisco description makes clear, this is not about them "getting directional" - it is about using the combined signals to/from multiple antennas to produce a more consistent signal that is less affected by multipath fading. The antennas used at the access point will have spatial separation, but in most implementations would be omnidirectional (just as in 802.11n MIMO deployments). In fact Cisco emphasise the benefits of this approach over a directional/beamforming solution.

Nevertheless this does not overcome three other fundamental issues associated with poor throughput in microcellular Wi-Fi, which in my experience generally have a greater impact on enterprise wireless performance - non-optimal AP selection by clients, co-channel interference and packet loss during roaming. All these issues are solved in Meru Networks' architecture.

Maybe people think it's a phone because ...

On the Nokia site http://www.nokia.co.uk/A4630128 it's listed under "phones" and the page has a section called "Get more from your phone with Nokia accessories".

UMTS macrocells

I'm afraid the poster has got his power sums completely wrong. I'm assuming he is getting his 27.9dBW figure from Ofcom's Sitefinder. This quotes power outputs in EIRPs (effective isotropic radiated powers), so is the figure AFTER all the antenna gains and cable losses. So the actual effective power in the main lobe is 617 Watts not 770 kilowatts.

In any case, his antenna gains are way out of whack. Firstly are the six antennas all part of the same array or are they covering separate sectors? Secondly are they transmit or receive antennas - receive antennas obviously don't count towards transmit gain? Thirdly, although 2 antennas will give an increase in gain of 3dB, you need to have 4 antennas to get 6dB and 6 would give 8dB - not 15dB.

RE: Can't overlap and others

I have to agree with others that much of Mr Kewney's article is a mix of the incomprehensible and the inaccurate (perhaps it was written by the other Guy?).

However on the 'can't overlap' issue he is generally correct.

Firstly with any vendor's system you can of course overlap the coverage of up to 3 11g access points because you have 3 channels that effectively do not interfere with one another. The problem comes when you have an office that needs more than 3 APs. You then have to reuse channels and in a 3 dimensional environment it is impossible to achieve the blanket coverage needed for telephony without coverage overlap (and hence interference) between APs on the same channel. Meru's single channel technology provides an effective solution to this problem.

Secondly, standard wireless access points are NOT viewed as a single access point. They may broadcast the same SSID, but they will be uniquely identfied by MAC address and clients will associate with a specific access point. This means that they need to roam when they move from access point to access point and unfortunately the roaming mechanisms in 802.11 are client initiated and pretty bad. By using a single channel and a common virtual MAC address, Meru shifts control of roaming to the infrastructure and hence delivers a much better user experience.