LTE - Resource Structure

-
Time Domain Structure

In the time domain, the signal is structured in the following parts:




Time Domain Signal Structure

Structure Element
Description
Radio Frames
10 ms length
Subframes
1 ms length. One frame consists of 10 subframes.
Slot
0.5 ms length. One subframe consists of two slots.
OFDM symbol
Approximately 71.4 μs length. One slot consists of 7 OFDM symbols.

  
Frequency Domain Structure
Orthogonal Frequency-Division Multiplexing (OFDM) utilize a large number of subcarriers. Each subcarrier is orthogonal to all other subcarriers. Subcarrier spacing is equal to the subcarrier bandwidth, which is 15 kHz, see Figure




Resource Element
The smallest resource unit handled in LTE consists of the combination of:
• The smallest time domain unit, one OFDM symbol
• The smallest frequency domain unit, one subcarrier

This unit is called Resource Element (RE). An RE that is not used for transmission is referred to as a hole

Resource Block
A number of REs are grouped into a physical Resource Block (RB). An RB is defined as follows:
• In the time domain: 7 OFDM symbol times (one slot)
• In the frequency domain: 12 consecutive subcarriers

Scheduling Block

A scheduling block consists of two RBs adjacent in time and with the same subcarriers. A scheduling block is the smallest unit that can be scheduled to user equipment.

Popular posts from this blog

SCFT - Single Cell Function test

-
Single Cell Function test SCFT is for verifying whether individual BTS works well or not, by making a single cell function test of BTS hardware and software. Essential items to be tested are as follows: 1) BTS Transmitter Output Measurement Test 2) Initial parameter establishment (Pilot PN/System ID/Site ID/Frequency, Neighbor List) 3) Call Origination and Termination Test 4) Softer Handoff Test/Antenna installation check (Direction, Tilt, Transmission Line) 5) Single Cell Coverage Test 6) Noise Floor Test 7) Parameter check.
Read more

Troubleshooting for GSM KPIs (SD Block & SD Drop)

-
KPIs to be monitored: ·             SD Blocking ·             SD Drop SDCCH Channel: ·    SDCCH channel is a dedicated channel which is using for LAC updation, Call Setup, SMS in Ideal mode. It works in UL & DL SD Blocking: ·    SD Blocking means that you are not getting SD resource for the call origination. When MS connects with Network then RACH and AGCH are provided. After AGCH, SDCCH is provided but if SDCCH is not provided at this time due to some problem or due to unavailable of SD by BSC. KPI Formula in Ericsson: ·             SDCCH CONGESTION = (CCONGS / CCALLS) * 100 ·             CCONGS - Congestion counter. ·  ...
Read more

PS core network

-
Image
The PS core network consists of two parts, the traditional General Packet Radio Service (GPRS) core network and the new Evolved Packet System (EPS) core network. The PS core network connects mobile subscribers to Packet Data Networks (PDNs) such as the Internet, corporate networks or operator services networks.  a functional overview of the PS core network. Logical entities and interfaces are shown in black and form a 2G/3G network, while the blue boxes and lines in Figure  show the LTE/EPC related parts. The LTE/EPC network can be regarded as an extension and evolution of existing 2G/3G networks. From a node implementation perspective, there is no strict border between the two networks. The corresponding logical entities of GPRS and EPS networks can be deployed concurrently in Ericsson PS core nodes, such as the SGSN-MME and EPG; these are marked in red. In addition, Ericsson GPRS nodes can be upgraded with EPC functionality by software only. Network evolution i...
Read more