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How to do VoLTE CSSR Optimization?

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VOLTE CSSR (Call Setup Success Rate) measures the success rate of establishing VoLTE voice calls, calculated as [L.E-RAB.SuccEst.QCI.1] / [L.E-RAB.AttEst.QCI.1] * 100. Degradation is commonly caused by X2AP procedure conflicts, S1 signaling failures, RRC connection issues, or core network processing delays. Main Principle X2AP Procedure Conflicts: During X2-based handovers, E-RAB (QCI 1) setup may conflict … Read more

How to do optimization of PS CSSR in LTE?

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To optimize PS CSSR (Packet Switched Call Setup Success Rate) in LTE, focus on improving RRC (Radio Resource Control) and E-RAB (Evolved Radio Access Bearer) setup success rates. Below is a structured approach based on technical principles. 1. Root Cause Analysis Weak Coverage: High TA (Timing Advance) values and cell-edge users cause RRC NoReply failures. … Read more

How to do RACH Optimization in 4G?

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To improve the RACH Completion Success Rate (RACH SR) in LTE, focus on optimizing parameters related to PRACH false alarm detection, RSI (Root Sequence Index) planning, and uplink interference mitigation. Below is a structured approach: 1. Principle Mechanism RACH SR degradation is often caused by: PRACH false alarms: eNodeB falsely detects preambles from UEs, leading … Read more

NR Drop Rate Optimization

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Case Study: High NR NSA Drop Rate on Top 11 Cells Problem:In a live NR NSA network, a consistently high drop rate was observed across the top 11 NR cells. The issue was persistent and impacting overall user experience, particularly for data and VoLTE services. Analysis:Initial checks included reviewing alarms, OPTLOGS, and BRD/CHR logs for … Read more

Massive MIMO with SU/MU MIMO

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Massive MIMO leverages large antenna arrays to enhance spectral efficiency through SU-MIMO and MU-MI MO techniques, improving coverage and capacity. 1. SU-MIMO in Massive MIMO 1.1 Uplink Receive Diversity Uplink Single-User MIMO (SU-MIMO) uses 32/64-antenna receive diversity to improve signal quality. The base station applies Maximum Ratio Combining (MRC) or Interference Rejection Combining (IRC) to … Read more

What are key differences between OFDM in 4G and F-OFDM in 5G?

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5G F-OFDM enhances 4G OFDM by improving spectrum efficiency through filtering, enabling higher data ra tes and flexible resource allocation. 1. Core Differences 1.1 OFDM in 4G 4G uses Orthogonal Frequency Division Multiplexing (OFDM) with fixed 15 kHz subcarrier spacing and large guard bands, achieving ~90% spectrum utilization. It lacks dynamic filtering, leading to higher … Read more