Shurish Subbramaniam

Reasons for low throughput in LTE Low throughput in LTE networks can be attributed to numerous factors spanning radio conditions, network configuration, and protocol behaviors. Radio Conditions 📡 Signal and Quality Issues: - Low SINR. - Poor RSRQ. - Downlink interference. - Uplink interference. - High BLER. - Modulation and Coding. - Resource Limitations (capacity). Network Configuration Issues 👨‍💻 - Cell Configuration (PCI, Wrong TAC planning, Incorrect parameter settings..) - Advanced Features (Carrier Aggregation, MIMO..) - Mobility Management (Handover). - Hardware Issues (High VSWR, Antenna, UE problems..) Core Network and Backhaul Issues 🌐 - Core network issues (MME/SGW, etc.) - Transmission instability and bottlenecks. Protocol Level Issues 🧾 TCP Performance Problems: - Limited TCP receive window. - Undesired TCP slow start occurring mid-flow upon packet loss. - Significant bandwidth underutilization. - Large buffers causing high queuing delays and increased RTT. - Inefficient application data transfer patterns. Protocol Overhead and Retransmissions: - HARQ inefficiencies. - RLC retransmissions. - Packet loss leading to additional retransmissions. - Poor RACH decoding SR. #Free_Palestine #Gaza #4G #5G #throughput #optimization #RF #وعلم_ينتفع_بة #Prophet_Muhammad (ﷺ) said: "The best of people are those who are most beneficial to people".

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Microwave Link Configuration 1+0 Definition: A single transceiver and antenna are used for transmission and reception without redundancy. Use Case: Suitable for applications where no backup is required and cost is a constraint. 2x(1+0) Definition: Two independent 1+0 links are used in parallel to provide higher capacity or for separate services. Use Case: Used for capacity enhancement or segregation of traffic. 1+1 HSB (Hot Standby) Definition: Two transceivers and antennas are configured on the same frequency (f1), with one acting as the active link and the other as a standby link. The standby link activates in case of failure. Use Case: Provides redundancy with automatic switchover for critical systems. 1+1 FD (Frequency Diversity) Definition: Two transceivers operate simultaneously on different frequencies (f1 and f2) for redundancy. If one frequency fails, the other continues operation. Use Case: Used in areas with high interference or fading conditions. 1+1 SD (Space Diversity) Definition: Two antennas at different physical locations (to mitigate multipath fading) transmit and receive on the same frequency (f1). Both antennas feed the same transceiver. Use Case: Ideal for environments prone to fading caused by terrain or obstructions. XPIC (Cross-Polarization Interference Cancellation) Definition: Two transceivers operate on the same frequency (f1), but each uses a different polarization (horizontal or vertical). The interference is canceled out electronically. Use Case: Maximizes capacity in a single frequency channel using polarization multiplexing. N+1 Definition: N working transceivers operate on distinct frequencies (f1, f2, ..., fn), with one additional transceiver serving as a protection unit. The protection unit takes over in case of any working transceiver failure. Use Case: Commonly used in multi-channel links to ensure service continuity with minimal redundancy cost.

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Here’s a simplified SRVCC call flow : SRVCC stands for Single Radio Voice Call Continuity. It is a 3GPP standard feature that enables the seamless handover of an ongoing voice call from an LTE (4G) or NR (5G) network to a circuit-switched (CS) network like 3G (UMTS) or 2G (GSM) when the user moves out of LTE/5G coverage. [1] UE – Active VoLTE Call via IMS ↓ [2] eNodeB detects poor LTE radio ↓ [3] eNodeB → MME: SRVCC Handover Required ↓ [4] MME → MSC-S: Prepare Handover (via Sv interface) ↓ [5] MSC-S allocates CS resources in UTRAN (3G) ↓ [6] MSC-S → MME: Handover Command ↓ [7] MME → eNodeB: Forward Handover to UE ↓ [8] eNodeB → UE: Command to Handover to 3G ↓ [9] UE connects to UTRAN (RRC connection) ↓ [10] 3G NodeB → MSC-S: Call Setup Complete ↓ [11] IMS → ATCF: Switch voice path to 3G leg ↓ ✅ Call continues on 3G without dropping

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Capacity optimization - 4G/5G To ensure that the user gets sufficient resources in the radio network (especially during busy hours), it is imperative to equip the radio access network with the right amount of capacity. Capacity should not be under or over provisioned. Over-provisioning leads to inefficient network whereas Under-provisioning can lead to poor customer experience by degrading key KPIs such as accessibility (no resources), mobility (Handover issues), integrity (poor user throughput) etc. 💠 To avoid scenario of under/over provisioning of capacity, following reports can be looked at : – ·      Busy Hour Utilization – measures the utilization of equipped resources in terms of Resource blocks or CCEs and its correlation with user experience such as throughput. ·       Traffic volume - measures the traffic carried by each cell (identify outliers). ·       Blocking – when resources are unavailable in the cell to use (for control & shared channel)- indicates which cells to be addressed first. ·       Backhaul congestion – Resources at the backhaul are insufficient & to be addressed. 💠Some of the ways to resolve capacity related issues – ·       By ensuring radio resources among control and shared channels are allocated appropriately (e.g., allocation of resources among PCFICH, PHICH, PDCCH (CCEs), PDSCH etc.) ·       By improving quality of the network (reducing weak coverage, overlapping, overshooting, interference etc.) as better quality helps to send more bits in same no of resources. ·       By enabling load balancing among different cells in a cluster. ·       Lastly by adding capacity in terms of new antenna, cells, sites, backhaul or carrier (if available). Note - There are few other actions that can be taken but above are the key actions be taken during capacity optimization. 👉 To learn more about the network optimization, refer to the course - https://lnkd.in/e9TpSHzF

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🔊 𝗩𝗼𝗟𝗧𝗘 𝗠𝘆𝘀𝘁𝗲𝗿𝘆: 𝗧𝗵𝗲 𝗢𝗻𝗲-𝗪𝗮𝘆 𝗩𝗼𝗶𝗰𝗲 𝗣𝗿𝗼𝗯𝗹𝗲𝗺 The call connects successfully… …but only 𝗼𝗻𝗲 𝘀𝗶𝗱𝗲 𝗰𝗮𝗻 𝗵𝗲𝗮𝗿 𝘁𝗵𝗲 𝗼𝘁𝗵𝗲𝗿. 👉 A nightmare for subscribers — and a classic troubleshooting case for engineers. ⸻ 📡 𝗪𝗵𝘆 𝗜𝘁 𝗛𝗮𝗽𝗽𝗲𝗻𝘀 One-way voice in VoLTE is almost never about signaling. It’s a 𝗺𝗲𝗱𝗶𝗮 𝗽𝗮𝘁𝗵 𝗶𝘀𝘀𝘂𝗲 (𝗥𝗧𝗣). 🔍 𝗧𝘆𝗽𝗶𝗰𝗮𝗹 𝗥𝗼𝗼𝘁 𝗖𝗮𝘂𝘀𝗲𝘀: 1. 𝗥𝗧𝗣 𝗔𝗻𝗰𝗵𝗼𝗿𝗶𝗻𝗴 𝗙𝗮𝗶𝗹𝘂𝗿𝗲 • Media path isn’t anchored correctly at the IMS border (P-CSCF/SBC). 2. 𝗖𝗼𝗱𝗲𝗰/𝗦𝗗𝗣 𝗠𝗶𝘀𝗺𝗮𝘁𝗰𝗵 • Caller and callee negotiate incompatible codecs (e.g., AMR-WB vs AMR-NB). 3. 𝗡𝗔𝗧 𝗧𝗿𝗮𝘃𝗲𝗿𝘀𝗮𝗹 𝗜𝘀𝘀𝘂𝗲𝘀 • Firewalls or NATs block RTP flow in one direction. 4. 𝗕𝗲𝗮𝗿𝗲𝗿/𝗤𝗼𝗦 𝗙𝗮𝗶𝗹𝘂𝗿𝗲𝘀 • Dedicated bearer (QCI=1) setup fails → media can’t flow properly. 5. 𝗜𝗻𝘁𝗲𝗿𝗰𝗼𝗻𝗻𝗲𝗰𝘁 / 𝗥𝗼𝗮𝗺𝗶𝗻𝗴 𝗜𝘀𝘀𝘂𝗲𝘀 • Media path broken across different operator networks. ⸻ 🛠️ 𝗧𝗿𝗼𝘂𝗯𝗹𝗲𝘀𝗵𝗼𝗼𝘁𝗶𝗻𝗴 𝗖𝗵𝗲𝗰𝗸𝗹𝗶𝘀𝘁 • Check SIP traces → INVITE / 200 OK SDP (codec negotiation). • Capture RTP streams → see if one side is missing RTP packets. • Verify bearer establishment in EPC (default + dedicated). • Look for NAT/firewall blocks (common in VoWiFi scenarios). • Compare KPIs: • VoLTE Call Setup Success Rate (OK but voice fails). • Dedicated Bearer Success Rate. • MOS / RTP Packet Loss. ⸻ ✅ 𝗧𝗮𝗸𝗲𝗮𝘄𝗮𝘆 If your VoLTE calls connect but users complain of “𝗜 𝗰𝗮𝗻’𝘁 𝗵𝗲𝗮𝗿 𝘁𝗵𝗲𝗺”, it’s a 𝗺𝗲𝗱𝗶𝗮 𝗽𝗹𝗮𝗻𝗲 𝗽𝗿𝗼𝗯𝗹𝗲𝗺, 𝗻𝗼𝘁 𝘀𝗶𝗴𝗻𝗮𝗹𝗶𝗻𝗴. Fixing RTP anchoring, codec alignment, and dedicated bearers is the key. ⸻ 👉 Have you faced one-way voice in your network? Was it more often 𝗰𝗼𝗱𝗲𝗰 𝗺𝗶𝘀𝗺𝗮𝘁𝗰𝗵 𝗼𝗿 𝗯𝗲𝗮𝗿𝗲𝗿 𝗳𝗮𝗶𝗹𝘂𝗿𝗲? #VoLTE #IMS #Troubleshooting #CoreNetwork #Telecom

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🚀 Demystifying 5G NR & VoLTE: The Backbone of Modern Voice Communication 📶 As we transition into the 5G era, understanding how voice services evolve is crucial. Let’s break down two key technologies: VoLTE (Voice over LTE) and VoNR (Voice over New Radio) — the voice engines of 4G and 5G respectively. 🔍 What is VoLTE? VoLTE allows voice calls over the 4G LTE data network using packet-switched protocols. It replaces legacy circuit-switched systems and offers: 📞 HD voice quality ⚡ Faster call setup 📶 Simultaneous voice + data 🎯 Guaranteed QoS via dedicated bearers 🔍 What is VoNR? VoNR is the 5G-native version of VoLTE, built on the 5G Standalone Core (5GC). It delivers: 🧠 Cloud-native, modular architecture 🕸️ Ultra-low latency 📡 Seamless voice over 5G NR without LTE fallback 🛠️ Dynamic QoS and scalability 🧠 Architecture Comparison: VoLTE vs VoNR. 🧩 Both rely on the IMS Core for call control and multimedia services, but differ in their core network: EPC (Evolved Packet Core) for VoLTE 5GC (5G Core) for VoNR, using Service-Based Architecture (SBA) 💡 Why It Matters Voice is still king in mobile communication. VoLTE and VoNR ensure that voice services are: 𝗥𝗲𝗹𝗶𝗮𝗯𝗹𝗲 𝗛𝗶𝗴𝗵-𝗾𝘂𝗮𝗹𝗶𝘁𝘆 𝗙𝘂𝘁𝘂𝗿𝗲-𝗿𝗲𝗮𝗱𝘆 Whether you're optimizing networks or designing next-gen apps, understanding these technologies is essential. Please Like and follow for more interesting content . I am open for discussion , please let me know your thought about it . #5G #VoLTE #VoNR #Telecom #NetworkArchitecture #IMS #TechSimplified #DigitalTransformation

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