If I have LTE system with assumption of peak data rate is 86 Mbps (only 50 resource blocks (RB) are available out of 100 RB with LTE system bandwidth 20 MHz), and there are two users with data rate 50 Mbps (user 1) and 60 Mbps (user 2), try to stream a video of 4 MB in size, I am wondering how much bits a user will get in each allocation of resources.
My current understanding is, as long as the data rate of users are below the peak data rate level, in each allocation (1 ms or one TTI) the system can always support one of the two users.
The amount of bits the system (eNode B) can give for the user 1 in each allocation (1 ms), is 50 Mb/1000 sec = 50 kbits. Is my understanding correct?
Thank you in advance.
The actual data rate depends on the scheduling procedure, SINR, modulation order, latency, etc.
Regarding your question, you may find the following link helpful.
https://www.slideshare.net/veermalik121/throughput-calculation-for-lte-tdd-and-fdd-system
Dear Uri,
According to LTE specifications, for 10 MHz bandwidth channels, the number of resource blocks= 50, each resource block is assigned 12 sub carriers for the duration of 0.5 seconds of 6-7 ofdm symbols. The number of bits in one resource block= 12x7x no. of bits per subcarrier which is equal to the log2 M , with Mis the QAM order. The highest QAM order is 64 and the highest number of bits per subcarrier=6. It follows that one resource block contains at most 12x7x6=504 bits. With 50 RBs then the total amount of data in 0.5 seconds= 25.2 kbits. The bit rate will be then= 25.2/.5ms= 50.4 Mbls. In case of 20Mhz with 100 RBs, then the maximum bit rate will be double of that which i calculated, that is 100.8Mb/s,
For 50 Mbls one has to assign x blocks= (50/100.8)x total no. of resource blocks(100)= one has to assign 50 resource blocks, and in case of 60 Mbls the number of assigned RBs= (60/100.8) 100=60.
In one second the transmitted bits will be 50Mbits and 60 Mbits respectively.
Best wishes
Hi Abdullah, thank you for the link, it is really helpful.
And also thank you Abdelhalim for such a thorough explanation. But, still the allocation is done in one millisecond instead of one second, right?
Yes, right, it is not intentional. As stated the time slot lasts .5 ms and two time slots makes out two two slots. For one 1ms, the size for transmitted bits are 50 or 60 Kbits for transmission rates of 50 or 60 Mb/s.
Best wishes
Hi Abdelhalim, thank you again for your response.. and happy Ramadhan!
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