LTE Concept and Applications

SR (Scheduling Request) is a request of scheduling radio resource for uplink transmission by the UE to the eNB. UE send SR on PUCCH when regular BSR (Buffer status report) is triggered and UE does not have radio resource to transmit this BSR to eNB.  To send this SR, UE must be configured with SR periodicity. If PUCCH resource is not configured for SR, UE start RA (Random Access) procedure. Since PUCCH resource is limited, SR periodicity should not be very less (short periodicity leads to fast resource allocation). If we fix short periodicity for SR, UE may not utilize the PUCCH for SR transmission allocated each time (UE may not have data to transmit in uplink always).   There must be a tradeoff between PUCCH load and SR periodicity.  UE always keep track of SR transmission on PUCCH. After reaching the maximum number of SR transmission (SR Max) and UE has not been allocated any radio resource for uplink transmission, it releases PUCCH resource for SR and s...

   Peak download data rate 100Mbps for 20MHz bandwidth        Peak uplink data rate 50Mbps for 20MHz bandwidth        Different spectrum bandwidth support from 1.2MHz to 20MHz        To provide best internet experience , packet based architecture        Performance should be equal up to 5KM radius from cell center        High performance mobility support up to 120KM/H        Connection maintenance up to 500KM/H        Support for at least 200 active users per cell of bandwidth equal to 5 MHz.        Packet delivery latency should not be more than 5 ms        Connection establishment latency should not be more than 100 ms. Questions are welcome.