Tuesday, December 22, 2015

WiFi: What is beacon bursting? What are the tradeoffs?

Beacon bursting is a mechanism by which beacon frames for all the BSSs (Virtual APs) running on that radio are sent out one after the other instead of spreading them out equally in time over the beacon interval. The other approach to sending beacons is to spread them out equally over the beacon interval.

For example, consider the beacon interval is 100msec and you have 5 VAPs beaconing, then, with bursting all the beacons are sent back to back after the beacon interrupt. However, if you are not using bursting, beacons are spread across the 100msecs. Hence, every 20msec the radio will send out the beacon of a different VAP.

Wednesday, December 2, 2015

WiFi: Comparison of WiFi Direct vs WiFi Aware vs BLE vs Adhoc mode (802.11)

WiFi Aware - service discovery that helps setup WiFi Direct links.
BLE - service discovery and P2P connection.
WiFi Direct - P2P connection
WiFi Adhoc mode - basic P2P connection (legacy mechanism)

We will now differentiate between each of these protocol suites and their applications.

WiFi Aware vs BLE
- WiFi Aware has a longer range (because of wifi power limits)
- works with existing WiFi chips (protocol overlay - Phy is mostly the same)
- higher bandwidth than BLE (faster for gaming etc) - this is because it will use WiFi Direct once wifi aware discovers the service.

- WiFi aware works across brands of phone vs ibeacons which will work only on iPhones for e.g.

Tuesday, November 17, 2015

Reliable Multicast for Enterprise WLANs

In this work, we have presented a complete end-end architecture to employ the rate-less codes. We have developed a new architecture Rate-less Codes Multicast (RCNC). This architecture is shown to provide high throughput gains, reliability and near optimal throughput performance.

Sunday, November 15, 2015

Idea: Smartphone dongle for police radar detection

Police radar detectors are still expensive - ranging up to $650 for good ones.  I was contemplating why good products in this area are not available for a lower price?

Possible Challenges:
1. Complex software running the blip detection (software DFS like?)

Friday, November 13, 2015

Uplink Airtime Fairness Control

Problem statement:
There is currently no direct way to control uplink airtime usage of wireless clients on a WLAN without actually implementing something on the client. This is not always possible because of multiple reasons:
Diversity in the operating systems and hardware of client devices.
Privacy issues
General aversion to install 3rd party control software.

Abstract of the idea:
In this case, we address the issue of limiting the airtime used the clients in the uplink direction by controlling the TCP window size in the uplink direction. We do this by doing a deep packet inspection of open TCP sessions for every client and then appropriately limiting the advertised TCP window based on bandwidth consumption by the clients.
Download PDF
Download Citation

Tutorial: 4 simple steps to create a quick heatmap in excel

  • Setup the data in your excel file:

  • Select your table and follow the next step

Tuesday, November 10, 2015

Hybrid Wireless Virtualization Architecture

This project presents the design of the hybrid wireless virtualization (HWV) controller based network architecture. Using a HWV controller, an unified approach can be taken for provisioning and management of virtualized heterogeneous radios, irrespective of their MAC and PHY mechanisms. It is shown that the airtime occupancy by transmissions from different slices or groups can be used as a single metric for tying these virtualized platforms.

Saturday, November 7, 2015

Multiuser support in WLANs versus Cellular networks

About a year back I was reading about the physical layer design of 802.11ac networks, and I started wondering about what would be the similarities or differences between cutting edge cellular networks and WiFi networks. The reason I started thinking about this is because cellular networks seem to be gradually moving towards smaller cells (nano-cell, pico-cell designs), which are similar in RF footprint to regular WLANs.