WiFi

I saw a survey result on the WiFi alliance pressroom.

Okay, the first question might be who or what is the WiFi Alliance ?

The Wi-Fi Alliance is a global, non-profit industry association of more than 250 member companies devoted to promoting the growth of wireless Local Area Networks (WLANs). With the aim of enhancing the user experience for mobile wireless devices, the Wi-Fi Alliance’s testing and certification programs ensure the interoperability of WLAN-Wireless Local Area Network.

Let me just give an idea on WHAT IS WiFi. Back in 2005 in Paris in the La D`efe'nse Metro Station, I saw something called a WiFi HotSpot Area. This really got me interested into the world of WiFi.

WiFi and related technologies like WiMax which is a derivative of WiFi is, a big rival for the "cellular networks" and there is a sort of "WAR" between the UMTS/HSDPA networks and the WiFi networks of hotspots. The next big question will be :- WHO will win in this war ?

The answer will be a function of quality of access, economic needs.
Also I think the two technologies should co-exist mututally complementing their respective natures.

Lets get into the basics of WHAT is a WiFi and how it can enhance your life ?

Wi-Fi, also, WiFi, Wi-fi or wifi, is a brand originally licensed by the Wi-Fi Alliance to describe the underlying technology of wireless local area networks (WLAN) based on the IEEE 802.11 specifications.

A person with a Wi-Fi device, such as a computer, telephone, or personal digital assistant (PDA) can connect to the Internet when in proximity of an access point. The region covered by one or several access points is called a hotspot. Hotspots can range from a single room to many square miles of overlapping hotspots

How WiFi Works ?

An Access Point broadcasts its SSID (Service Set Identifier, "Network name") periodically. There is a hardware on the WiFi Client which can be called a WiFi Card.

Based on the settings (e.g. the SSID), the client may decide whether to connect to an AP. Also the firmware running on the client Wi-Fi card is of influence. Say two APs of the same SSID are in range of the client, the firmware may decide based on signal strength to which of the two APs it will connect.

Some examples of WiFi Devices

Some of the prominent examples of WiFi devices could be Wireless Routers, VoIP Wi-Fi phones(the phones suck, in my opinion!!!). Infact,GSM phones with integrated Wi-Fi & VoIP capabilities are being introduced into the market and have the potential to replace land line telephone services.

There are several advantages and disadvantages of WiFi. I will take that up in a later post !!!

QoS in GPRS

Note :- This is a technical article. I have tried to make it look as simple as possible.

Web applications are of different types :-

a) I might be seeing and listening to a music video in YouTube on a mobile phone.
b) I might try to be accessing my email on my mobile phone.
c) I might try to talk using an IP phone.
d) I might try to download a video clip/application.

As we have different types of applications which I have labeled as a), b) c) and d) we also require a quality of service for each of the above web based application.

"a)" is an application whose nature may be defined as "streaming multimedia may require guaranteed throughput"

"b)" (and sometimes "d)" ) are examples of elastic web applications whose nature is very flexible. (elastic applications can take advantage of however much or little bandwidth is available.)

"c)" requires strict limits on jitter and delay.

Now given the different nature of the above web applications, How can GPRS (as a service) address these demands.

The answer, my friend, is QoS aka Quality of Service.

The QoS is a collection of different parameters which have been defined, redefined, abused from release to release. Let us have a quick look on the different parameters of QoS from a GPRS point of view.

Important note of the author
These are just major Release 99 parameters defined in the 3GPP specifications)

a)Precedence class :- This indicates the precedence/priority of an application. Once gain we have precedence 1 , precedence 2 and precedence level 3 classes.

b)Delay class :- The delay parameter is defined as the end to end transfer time between two MSs or between a MS and Gi interface (see Figure 3-1) to an external IP network

c)Reliability Class :- This talks about the reliability of a data transfer of an application.What are the dangers for a packet in a packet network ? It might get corrupted, it can get lost , it can be duplicated or it can be out of sequence. Reliability classes can be 1,2 or 3. 3 provides error correction and is not error sensitive at the receiver end. 1 is error sensitive and provides ZERO error correction.

d)mean throughput :- This is perhaps the most important and visible feature of the QoS. It is the mean octet per sec measure at the Gi interface!!!!

e)peak throughput class :- This is the peak octet rate per sec.

A realistic bit rate is 30–80 kbps, because it is possible to use max 4 time slots for downlink.

A change to the radio part of GPRS called EDGE(sometimes called EGPRS or Enhanced GPRS however it actually stands for Enhanced Data rates for GSM Evolution) allows higher bit rates of between 160 and 236.8 kbit/s.

IPTV anyone ?

IPTV is just TV programming services offered using internet.But the big question is :-
Do users really switch on to IPTV ? Is it really going to take over television ?
Is it going to result in an epic battle between the mobile operators like Ericcson and Orange ?

Or is it going to be a damp squib ?

The answer is simple.

Time will tell.

IPTV will definitely attract more subscribers because of its obvious advantages :-

a) I can see a program at any time I want see it.

b) Suppose I am watching a sports match. I dont like commentator "X". I can select a commentator "Y". This is something which is not under user control. (Atleast, right now , in India).

c)Suppose a reality show(or say a fashion show ) is being shown on IPTV , I can select the camera of mychoice and check out the program. (Okay I admit this is an advanced option, and it actually turns the user into a cameraman).

d)The last but not the least, you require an internet connection and a device like a PC or even as small as a 3G phone.Just imagine after a hectic meeting, you just switch on your mobile phone and watch a good comedy, presumably discreetly.You can also have a small screen in your car too.

e)Now suppose you watch an ad for a book. And you may click on it and an order and a delivery can be made. An instance of interactive advertising . This promises agressive advertising (which can smetimes be mailicious too)

The disadvantages of IP TV (according to me ) :-

0. Slow. You have to admit it. Right now an IP TV is in its infancy.But it may not match the quality of our regular broadcast Television

1. Many a time, I just want to switch on TV and browse a channel and just lay back. I may not know what exactly to watch !!

So as I saw the news article on zdnet, I thought I should pen my thoughts on IPTV :-)

Related links :-
a) ZDNET
b) iSuppli's survey on IPTV