Modules
- Modelling and Simulation of Physical and MAC Layer for WLAN (2.4 GHz & 5 GHz) for IEEE 802.11n & 802.11ac.
- MAC layer: Rate adaptation algorithms
- Coexisting WLAN networks
- Downlink Performance of OFDMA 802.11ax WLAN Networks in dense deployments.
Modeling and Simulation of Physical and MAC Layer for WLAN
Standards considered: 802.11n & 802.11ac at 2.4 GHz and 5 GHz
Performance metrics
–Throughput
–Latency
–Packet Error Rate
–Range
Models for various scenarios
–Scenario 1: Client at different distances from an Access Point
–Scenario 2: Client in motion WRT a single Access Point
–Scenario 3: Client in motion while covering multiple Access Points
Simulation Setup in MATLAB
![Matlab_Sim](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2020/09/Matlab_Sim.png)
MAC layer: Rate adaptation algorithms
- Rate adaptation is used to deal with variations in channel and interference
- Transmitter adapts its modulation and coding scheme (MCS) to get different rates
- A crucial algorithm that affects performance of Wi-Fi networks
- Factors that affect throughput:
- Dynamic nature of channel
- Interference from other WiFi transmitters
- Heterogeneous receiver capability
- Goal: Maximize throughput while containing packet error rate
Comparison of DRCA, Ideal RAA, and Minstrel:
![wi-fi-modelling (15)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-15.jpg)
Matlab’s Dynamic Rate Control Algorithm (DRCA):
![wi-fi-modelling (2)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-2.jpg)
Ideal Rate Control Algorithm:
![wi-fi-modelling (3)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-3.jpg)
Benchmarking: Ideal vs. DRCA (802.11ac):
![wi-fi-modelling (4)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-4.jpg)
Minstrel-HT Rate Control Algorithm:
- Evaluating the Matlab implementation of Minstrel-HT with a reference known as MinstrelHTWifiManager from NS3.
![wi-fi-modelling (6)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-6.jpg)
- Response of algorithm (MCS selection and MRR update) to packet failures/success given the same initialization and randomisations were matched.
![wi-fi-modelling (7)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-7.jpg)
MAC layer: Rate adaptation algorithms
- WLAN co-existence analysis inside a plane
- Analysing throughput between interfering APs
![wi-fi-modelling (8)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-8.jpg)
![wi-fi-modelling (9)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-9.jpg)
- Minstrel-HT integration with multi-node system-level simulations
![wi-fi-modelling (10)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-10.jpg)
- Simulated Rate adaptation in an increased number of WLAN networks
Downlink Performance of OFDMA 802.11ax WLAN Networks in dense deployments
- Gain of the MU-OFDMA feature of the 802.11ax standard provide
- 11ax vs 802.11n simulations: Implemented in Matlab
- 11n vs. 802.11ax
- Throughput-based scheduling for extreme fairness
![wi-fi-modelling (11)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-11.jpg)
- Scheduled access as opposed to contention-based access.
- Different RUs for different STAs depending on channel conditions.
- 11ax: OFDMA for MU transmissions
- Compare per-node throughput and latency
![wi-fi-modelling (12)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-12.jpg)
- Round-robin vs. throughput-based OFDMA scheduler
![wi-fi-modelling (13)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-13.jpg)
![wi-fi-modelling (14)](https://labs.dese.iisc.ac.in/zenlab/wp-content/uploads/sites/2/2023/06/wi-fi-modelling-14.jpg)
Ongoing and future work:
- Default round-robin scheduler in Matlab:
- RUs allocated based on the number of previous transmissions.
- STAs with the least number of transmissions at the start of each frame are allocated RUs.
- Throughput-based scheduler:
- RUs allocated based on the running value of throughput.
- STAs with the least throughput at the start of each frame are allocated RUs.
- Scheduled access vs. contention-based access:
- Allocating RUs based on SINR per RU for each STA.
People
Other Team members: Amol Bhindwale, Rushabha Balaji, Sourav Mukherjee, Vinay U Pai