A Maharastrian Wedding

Talking about wireless all the time can be quite boring and doing it all day is definitely not happening. Decided to take a break, I went to my friend's wedding in Western Mumbai today.

My friend is a Maharastrian from Mumbai. Maharastra is a Western part of India situated along the coastline of the Arabian sea. India's demography is very diverse. Every state has its own autistic people and language. Sometimes I wonder how these states, widely apart in their identity, glue together and resonate harmoniously to one tune called India.

Nevertheless, ride to the wedding was effortless. I boarded a train from my place, got off at a station, piggy-backed in my colleague's car and headed for the wedding. We lost our way in the middle, but after series of queries with the the side walker and few U turns we reached our place. After diligently parking the car at a risky place we entered into the hotel.

First thing that took my breadth was the agility with which the wedding was pacing. Almost, within two hours of its inception, the wedding entered into its final stage: The Reception.

Maharstrian wedding is generally shorter, lasting only for hours, than the average duration of weddings in India. Strategically organised on weekends to force large attendance, it is constantly hammered with the unavailability of space and cost that sometimes justify its premature ending.

It starts off with Bride and Groom standing in front of each other. A long white cloth separates them. They hold garlands in their hands, made up of handpicked flowers, patiently waiting for the priest to complete his perennial chantings of rituals. Guests, in the meanwhile, shower the couple with the flowers occasionally digressing into their own animated conversations. When the priest finally finishes, the bride and groom exchange garlands and the wedding is complete. There is no time for "Saath Phare" which is quite common in Northern India.

After this the lunch party begins and begins a hustle to get a nice picture with the couple on the stage. The parents of both the party also stand with them. I also walked up to the stage and congratulated the newly weds. Then, after sharing some light moments with my Colleagues and Friends over there, it was the time for me to go back home.

802.16e Network Architecture

First, A question: Who do you think is responsible for IEEE 802.16e Network architecture development? IEEE? No! Ironic to the common belief, Wimax network architecture development is the task of Network Working Group (NWG) of Wimax Forum.

I will cover this topic briefly because I, myself, have a very limited knowledge of this topic. This topic is so vast in itself that it is almost impossible to cover it into one posting or in one Blog. So, I will give you some pointers in the end that will impart deeper knowledge of networking in the Wimax.

Wimax network is an all IP network, supports all usage model(fixed and mobility) and has a provision to support different Quality of Service(QOS). It has open interface for both within the Radio Access Network(RAN) and between the RAN and the core network. It supports all type of Voice, Data and Multimedia services.

Wimax Network, as shown above, consist of two important element: Network Service Provider(NSP) and Network Access Provider (NAP). NAP has two important elements: Base station and Access Network Gateway(ASN). Where as ASN gateways connects and manages different Base stations, NSP provides connectivity to different backhand networks(e.g. IMS). Wimax network supports both IPv4 and IPv6 protocols.

Multiple ASN profiles has been provided in the Wimax to manage diversity in ASN implementation and usage.There are three different ASN profiles(A,B,C) that depends upon the location of ASN and BS and also on the status of different interfaces (R1, R2...). Interfaces provides physical and logical connection between various network entities. They can be open(Vendor specific) or closed(NWG specified).

You can find more information about network architecture here

Okay, in the next blog we will be starting introductory Medium Access Control(MAC) of Wimax. Cheers!

Wimax Forum

From now on, we would be going into the depths of Wimax. But first, there is a good comparison of the existing wireless standards, I have displayed at the top of this blog. The wimax row is encircled in red. Notice that LTE is much much higher in throughput than the Wimax. Neways, we are not going to talk about the LTE here, we are loyal to wimax :)

Okay, today I will talk about the operating frequency bands of the mobile Wimax. I will also introduce the Wimax forum. It should be noted that the IEEE only makes the standard- It only talks about the PHY and MAC. What lies behind is specified by the the Wimax Forum. WiMAX Forum is a non profit organization formed to promote the adoption of WiMax compatible products and services. It is the job of the Wimax Forum to ensure interoperability among the devices from different vendors. Wimax Forum also dictates the band of operations, various PHY and MAC profiles to be included in the releases and over all architecture of the Wimax network. Those who passes the conformance and interoperability test can claim their product is "Wimax certified". Others adopt names like "WiMAX-ready", "WiMAX-compliant", or "pre-WiMAX", if they are not certified by the Wimax Forum.

Wimax Forum talks about the band of operation in terms of system profiles. Currently, only two system profiles are being certified: 1)2.4 - 2.6 Ghz 2)3.3 - 3.5 Ghz for the 10 Mhz band. I have also heard that the 700 Mhz profile is also being introduced, the auction for which has already been taken place in North America. The frequency plays a major role in the success of Wimax, as the range decreases rapidly with the increase in operating frequency, it will be good to operate at lower frequency in rural areas. I have a cellular phone which works in a 1800 Mhz band, and trust me I hardly get any signal inside my home. I have to go out to make a decent quality call. Products for both the profile are already available in the market. I will post a related document soon. In my next blog, I will talk about the network architecture and MAC layers of the Wimax.

Wimax Wifi Fight

There is a big misconception that Wimax is a replacement of Wifi. Perhaps, this doc will clear many misconceptions about Wimax. Click on the wimax myth buster under the heading wimax related stuff. Wimax and Wifi are completely different technologies with different goals. While Wifi is designed for the LAN (Local Area Network), Wimax has been engineered for MAN (Metropolitan Area Network). More simply, Wifi is for indoor and Wimax is for outside coverage.

Although underlying physical layer technology is same for both the cases (OFDM). It’s the MAC (medium access control) that differentiates between the two. MAC is needed to coordinate transmission between many to one situation. Wimax Mac is connection oriented. A logical connection is first established before data can flow through. This guarantees a minimal quality of service (QOS). We will talk about Wimax QOS later n our discussion.

Wifi is connection less and more contentious with its CSMA (Carrier Sense Multiple Access) Mac. In this type of MAC, a competing subscriber station (SS) listens to the channel, and when the channel is free, request for the transmission. Quite a different stuff altogether!

Wifi is also limited in range. Owing to free 2.4 GHz ISM band it operates in, wifi energy in the air is restricted to only couple of 100 meters. Where as Wimax works in a licenses band and can go up to ten's of kilometers.

In my next blog, I will be talking about the bands of operation of Wimax and Wimax forum.

Wimax: Part I Introduction

Hi there! I am sorry, extremely sorry. I had been crazy busy with the work I absolutely didn't get time to write. Nevertheless, as they say, better late than never. Let’s kick off and explore Wimax.

Wimax- Wireless Interoperability for Microwave Access. Purported as the last mile solution, this technology can deliver ubiquitous coverage in the range of 30 – 75 Mbps. But, before we go any further, we need to ask ourselves a simple question: why do we need Wimax? There are dearth of other wired and wireless technologies available, like: ADSL, Wifi, CDMA and GSM. So, why wimax?

If look at the statistics of wireless internet demand over the years, it should be pretty clear that, with the advent of multimedia rich mobile applications like you tube, web messenger etc, the demand for high speed internet is increasing exponentially.

Early usage of wireless internet was limited to e-mails and content browsing. But this is now changing very rapidly. We want to download music, watch videos, view content rich email attachments and do video conferencing. All these stuffs put tremendous burden on the existing wireless technologies that have very limited data rates.

But some may argue: we do have ASDL. Don’t we? Yes, we do have ADSL, but then is it possible to cover entire globe with wires? Don’t we feel liberated whenever we have a wireless substitute? The problem is more exaggerated in the case of developing countries, where the existing infrastructure is insufficient to support wired access to every one. So, in order to fill this huge gap of coverage and capacity, Wimax has been developed.

So, till I write my next blog, convince yourselves that we really need Wimax. I would be glad, if you invent some and write here based on your experience. In the next blog, I would be comparing Wimax with Wifi; An obvious comparison that comes in everybody’s mind.

Why max ?

Okay, I have figured out the contents of the wimax series. I will be covering all aspect of wimax, except handover (Coz haven't done it myself :)). In two months, I will tell you about:

1)Introduction (1 week)

2)Medium Access control (3 weeks)

3)Physical Layer (3 weeks)

4)Summary + Practical issues (1 weeks)

The focus will be more on practical than academics. I will not go into deep, but you are welcome to ask question pertaining to the discussion. For more clarity, I will be providing online consultancy in my off work hours through Bit wine consultancy. You can book a prior appointment. To know more about me visit peak2average.blogspot.com

Your comments are welcome!!

Coming Soon !

Starting from October 1, I will be writing an educative series on Wimax 802.16e. Covering Phy and Mac, you will get a comprehensive view of this exciting technology. You can also get your doubt (except IPR) solved through my Bitwine personal consultancy at a very nominal rate. I will be posting the link to which soon. So check my blog regularly !