The difference between OFDM and OFDMA and how they work
The difference between OFDM and OFDMA and how they work
OFDMA means orthogonal frequency division multiple access
It means that more than one user can use the channel at the same time and send and receive data on it.
The essential difference between OFDM and OFDMA is that
in OFDM, each user is assigned a channel and uses it all the time, and this is the disadvantage that it makes low channel usage utilization, which means the use of poor resources and the frequency of the channel means, in the correct sense, a waste of the channel
But in OFDMA, more than one user data is sent and received on the same channel at specific times called time slots
OFDMA is known as 802.11ax
Its advantages are that it divides the frequency band used in the system into a group of small sections called subcarriers and starts giving users a group of subcarrriers in specific time slots to send data on
The number of subcarriers is determined according to the bandwidth required by the user, which is also determined by the type of service used by the user.
Example of service types:
Web browsing
Email
Streaming
Chat / instant message
Download
Voice call
Video call
We can say that OFDMA allows more than one user to use different types of service.
They use the same channel at specific time slots, thus making channel usage Utilization
And from here. We have a term called RU, which means resource unit, and it is a combination of frequency and time
It means we will give the user a certain number of subcarriers for a certain period of time
A practical example of comprehension. If you have a channel size of 2 MHz, it will be divided into 26 subcarriers, and this is considered the least needed in the types of OFDMA channels.
The biggest thing is 77.8 MHz, which is divided into 996 subcarrrier horn antenna.
Thank you.
