Factors Affecting Throughput in LTE :- Low mcs, Low sinr, Low rsrq , high prb usage, wrong earfcn Definition, no Carrier aggregation ör missing ca configuration, Pci , Route sequence index collision, Wrong tac planning, gateway security problem, etc. air quality (now sinr, rsrq, etc etc), modulation level. For example, 16QAM, 64QAM, etc. Low Throughput Issue:- 1 - Poor coverage (BLER) 2 - Availability issue 3 - Uplink Interference 4 - A poor RACH decoding SR 5 - High error on S1 link. 6 - Delay on S1 link towards MME & SGW. 7 - Accessibility issue. 8 - Handover failure. 9 - Lack of PRBs. 10 - Problematic UE. 11 - Downlink Interference (Bad CQI) 12 - MIMO Parameters 13 - High VSWR 14 - High radio errors or instability issue. 15 - Maximum number of RRC connections active per cell 16 - Maximum number of users per TTI supported per cell. 17 - Core network, MME/SGW, etc 18 - Transmission instability & bottleneck. 19 - Incorrect parameter setting. 20 - Badly tuned handover parameters...
BURST AND FRAMES :
A Burst is a formatted sequence of bits during one-time slots.
Due to TDMA structure with time slots, we do not send continuously but only in the designated time slots. The information sent during one time slot is formatted into a Burst.
Types of Burst:
1) Normal Burst (NB):
It is used to carry information on traffic and control channels.
The normal burst contains;
· 2 information fields, each with 57 bits, used for encrypted speech or data
· One training sequence to be used by the equalizer in the receiver
· 2 bits to indicate whether the burst is “stolen” to be used as a FACCH
· 3 bits in each end to serve as start and stop bits.
2) Access Burst (AB):
It is for random access and handover access.
The Access burst is as short as possible, to allow a certain delay without interfering with the next time slots.
3) Synchronization Burst (SB):
It is used for frame synchronization of the mobile. To know the when certain information is broadcasted.
4) Frequency Burst (FB):
It is used for frequency synchronization of the mobile.
5) Dummy Burst (DB):
It is used when on other type of burst is to be sent.
THE RELATIONSHIP BETWEEN BURST AND FRAMES
There are two types of multiframes
· 26 TDMA frame multiframes are used to carry TCH, SACCH and FACCH.
· 51 TDMA frame multiframes are used to carry BCCH, CCCH, SDCCH and SACCH.
The superframe consists of 26 or 51 multiframes and hyperframe consists of 2048 superframes.
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