LTE TDD # Technology Definition

Hello my teammates , my article today will discuss LTE TDD Basic knowledge when an operator have been decided to start deployment LTE TDD beside currently LTE FDD band. We will discuss LTE TDD band definition and CS voice call methodology.

Global LTE TDD Spectrum distribution:

Below snap shows that most common LTE TDD spectrum globalization

Power budget calculation have been effected for LTE TDD vs LTE FDD: this is important factor for LTE TDD that have lower inter-site distance than FDD that because UEs power limitation in UL that will contribute 50% in Tx power if UL/DL ratio configured is 1:1. Assuming same transmit power . The main reason for reduced coverage is that the uplink device power is used part of the time for TDD but continuously for FDD . As an example, an 1:1 UL/DL allocation means a duty cycle of ~50% in the uplink which contributes to a ~3dB reduced link budget In capacity driven deployments, there is no coverage advantage.

That requires to deploy LTE TDD in hotpots areas with better smoothly HO toward FDD while UE modes away from cell center to cell edge :: Move far away from cell center --gt; TDD To FDD coverage base HO.Serving below cell center --gt; May implement TDD+FDD Carrier Aggregation to throughput enhanced regarding Cell center Users.

What is methodology for CS Voice call for LTE TDD:

Is similar to FDD as we have two options:

CS Fallback to legacy technologies (3G/2G).or VoLTE call on TDD or FDD with enabling SRVCC to legacy technologies (3G/2G)

Reference :: QualCoMM articles.