Gaurang Radadiya

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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4G LTE Call Flow (VoLTE) – IMS Based Voice Call Step-by-Step Call Flow --- 1. UE Attach to Network: UE → eNodeB → MME: Attach Request MME → HSS: Authentication MME → SGW → PGW: Create Session Request (Default bearer for IMS APN) 2. IMS Registration: UE → P-CSCF → I-CSCF → HSS → S-CSCF Authentication with IMS (using SIP REGISTER) 3. SIP Voice Call Setup (MO Call) UE → SIP INVITE → P-CSCF → I-CSCF → S-CSCF S-CSCF → Terminating UE via P/I/S-CSCF: INVITE 4. Voice Bearer Setup: IMS core instructs both UEs to establish RTP bearer eNodeB → SGW/PGW → Internet (voice media path using RTP) 5. Call Connect: SIP 200 OK exchanged → ACK → Voice call active 6. Call Termination: SIP BYE from either side → SIP 200 OK → Call ends #5G #4G #VoLTE #VoNR #CallFlow #IMS #CoreNetwork #Telecom #Telecommunications #WirelessTechnology #MobileNetworks #RANEngineer #NetworkEngineer #SystemIntegrator #KnowledgeSharing #LearningNeverStops #TelecomTraining #TechCommunity #TechPost #Infographic #TrendingTechnology #FutureOfConnectivity #DigitalTransformation #eNodeB #gNodeB #MME #AMF #UPF #PDU #QoS

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📡 𝗩𝗼𝗡𝗥 𝗥𝗲𝗴𝗶𝘀𝘁𝗿𝗮𝘁𝗶𝗼𝗻 𝗙𝗮𝗶𝗹𝘀 — 𝗪𝗵𝗲𝗻 𝗜𝗠𝗦 𝗗𝗼𝗲𝘀𝗻’𝘁 𝗙𝗼𝗹𝗹𝗼𝘄 𝟱𝗚 𝗥𝘂𝗹𝗲𝘀 In LTE, IMS registration is usually smooth. But in 5G Standalone (SA), many engineers are seeing something strange: ✅ 5G coverage is strong ✅ PDU session established ❌ IMS registration fails Why? Because IMS in 5G doesn’t play by the same old EPC rules. ⸻ 🔍 𝗪𝗵𝗮𝘁’𝘀 𝗔𝗰𝘁𝘂𝗮𝗹𝗹𝘆 𝗛𝗮𝗽𝗽𝗲𝗻𝗶𝗻𝗴 In VoNR (Voice over New Radio), the IMS registration still uses SIP over IP — …but it rides on a 𝟱𝗚 𝗤𝗼𝗦 𝗙𝗹𝗼𝘄 instead of an LTE bearer. That means policy, routing, and QoS enforcement now depend on: • 𝗔𝗠𝗙/𝗦𝗠𝗙 for session setup • 𝗨𝗣𝗙 for user-plane routing • 𝗣𝗖𝗙 for IMS-related policy control When any of these are misaligned → IMS traffic never reaches the P-CSCF. ⸻ ⚠️ 𝗧𝘆𝗽𝗶𝗰𝗮𝗹 𝗙𝗮𝗶𝗹𝘂𝗿𝗲 𝗖𝗮𝘂𝘀𝗲𝘀 𝟭. 𝗗𝗡𝗦 𝗥𝗲𝘀𝗼𝗹𝘂𝘁𝗶𝗼𝗻 𝗙𝗮𝗶𝗹𝘀 • IMS FQDN not reachable via 5G DNS (different domain from EPC). 𝟮. 𝗤𝗼𝗦 𝗙𝗹𝗼𝘄 𝗠𝗶𝘀𝗰𝗼𝗻𝗳𝗶𝗴𝘂𝗿𝗮𝘁𝗶𝗼𝗻 • Missing 5QI=5 (signaling flow) → SIP packets get dropped. 𝟯. 𝗣𝗖𝗙 𝗣𝗼𝗹𝗶𝗰𝘆 𝗡𝗼𝘁 𝗔𝗽𝗽𝗹𝗶𝗲𝗱 • IMS traffic not classified as high-priority → blocked at UPF. 𝟰. 𝗦𝗲𝗰𝘂𝗿𝗶𝘁𝘆 𝗣𝗼𝗹𝗶𝗰𝘆 𝗠𝗶𝘀𝗺𝗮𝘁𝗰𝗵 • Incorrect NASS/AVP parameters → IMS rejects REGISTER request. 𝟱. 𝗜𝗣𝘃𝟲-𝗢𝗻𝗹𝘆 𝗥𝗼𝘂𝘁𝗶𝗻𝗴 𝗜𝘀𝘀𝘂𝗲𝘀 • IMS core not reachable from IPv6 PDU sessions. ⸻ 📈 𝗞𝗣𝗜𝘀 𝘁𝗼 𝗪𝗮𝘁𝗰𝗵 • 𝗩𝗼𝗡𝗥 𝗥𝗲𝗴𝗶𝘀𝘁𝗿𝗮𝘁𝗶𝗼𝗻 𝗦𝘂𝗰𝗰𝗲𝘀𝘀 𝗥𝗮𝘁𝗲 (%) • 𝗣𝗗𝗨 𝗦𝗲𝘀𝘀𝗶𝗼𝗻 𝗘𝘀𝘁𝗮𝗯𝗹𝗶𝘀𝗵𝗺𝗲𝗻𝘁 𝗦𝘂𝗰𝗰𝗲𝘀𝘀 𝗥𝗮𝘁𝗲 • 𝗦𝗜𝗣 𝟰𝟬𝟯/𝟰𝟬𝟰/𝟰𝟴𝟬 𝗙𝗮𝗶𝗹𝘂𝗿𝗲 𝗥𝗮𝘁𝗶𝗼 • 𝟱𝗤𝗜 𝗙𝗹𝗼𝘄 𝗖𝗿𝗲𝗮𝘁𝗶𝗼𝗻 𝗦𝘂𝗰𝗰𝗲𝘀𝘀 𝗥𝗮𝘁𝗲 ⸻ 🛠️ 𝗧𝗿𝗼𝘂𝗯𝗹𝗲𝘀𝗵𝗼𝗼𝘁𝗶𝗻𝗴 𝗔𝗽𝗽𝗿𝗼𝗮𝗰𝗵 • Trace SIP REGISTER messages from UE → UPF → IMS. • Check DNS resolution in 5G domain (IMS APN vs default APN). • Correlate SMF/PCF logs for missing policy rules. • Validate QoS Flow (5QI=5) creation and enforcement in UPF. ⸻ ✅ 𝗧𝗮𝗸𝗲𝗮𝘄𝗮𝘆: 𝗩𝗼𝗡𝗥 𝗶𝘀𝗻’𝘁 𝗷𝘂𝘀𝘁 𝗩𝗼𝗟𝗧𝗘 𝗼𝗻 𝟱𝗚. IMS registration in 5G depends on SMF, PCF, and UPF cooperation — not just MME and SGW anymore. If any of those layers fail to route or prioritize SIP traffic, voice disappears before it even starts. ⸻ 👉 Have you tested VoNR registration in your network? Did your failures come from IMS policy misalignment or UPF routing issues? #5G #VoNR #IMS #CoreNetwork #Telecom #Troubleshooting

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VoLTE (Voice over LTE) is a technology that enables voice calls as IP packets over 4G LTE networks using IMS. It provides HD voice quality, faster call setup, and simultaneous voice and data, delivering a seamless all-IP communication experience in modern mobile networks.. Step-by-Step IMS LTE VoLTE Voice Call Flow 1. **Initial Network Attach (EPS Attach):**   - UE (User Equipment, e.g., mobile) sends an RRC Connection Request and completes authentication with LTE EPC (MME/S-GW/P-GW). Default bearer with QCI=5 is established for signaling. The IMS APN is used for SIP traffic. 2. **P-CSCF Discovery & SIP Registration:**   - UE discovers the IMS Proxy-CSCF (P-CSCF) via DHCP or ISIM.   - UE sends SIP REGISTER to P-CSCF; this is routed to I-CSCF and S-CSCF in the IMS, with HSS handling authentication through a nonce-challenge. On success, 200 OK is sent to UE; IPsec security is established for SIP signaling. 3. **Voice Call Initiation (SIP Invite):**   - UE generates a SIP INVITE containing SDP (Session Description Protocol) offer with media types, codecs (e.g., AMR-WB for HD voice), and QoS requests.   - INVITE routes via P-CSCF → S-CSCF→ (optionally TAS, ENUM, BGCF, MGCF if terminating off IMS). 4. **Call Progression and Bearer Setup:**   - Each hop responds with “100 Trying.”   - The terminating UE replies with “183 Session Progress,” providing an SDP answer.   - Dedicated LTE bearers with QCI=1 are established for voice packets using PCRF, guaranteeing low delay and packet loss. 5. **Reliability & Resource Reservation:**   - Calling UE sends PRACK (Provisional Response ACK) to acknowledge the 183 message.   - Negotiated codecs and confirmed media settings are confirmed with SIP UPDATE/200 OK UPDATE. 6. **Alerting & Answer:**   - “180 Ringing” indicates the destination is alerting.   - Called party answers, sending “200 OK” for the INVITE. 7. **Call Establishment & Media Flow:**   - Calling UE sends final SIP ACK; bi-directional RTP flow for voice media starts directly between UEs on dedicated bearers.   - The IMS/SIP path manages any mid-call signaling or supplementaries . High-level IMS/LTE/VoLTE call flow diagram example: 1.UE → eNodeB → EPC (MME / SGW / PGW) → IMS: P-CSCF → I-CSCF → S-CSCF 2.SIP Messages sequence: REGISTER, INVITE, 100 Trying, 183 Session Progress, PRACK, UPDATE, 180 Ringing, 200 OK, ACK 3.RTP media: Direct between UEs over LTE. Please follow for more informative content. ... #IMS #VoLTE #LTE # #Cloud

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🔧 Understanding the Role of PRACH Index in LTE Systems 💡 In LTE networks, the Physical Random Access Channel (PRACH) is a crucial component that allows User Equipment (UE) to connect to the network for services like initial access and handovers. But ever wondered how the network differentiates each access attempt? That’s where the PRACH Index comes into play. Here’s a breakdown of why the PRACH Index is so important for efficient random access: 🔸 What is PRACH Index? It’s a unique identifier used by UEs to select specific preamble sequences for random access. Think of it as the “address” of a request, telling the eNB when and where the request is coming from. 🔸 Why It Matters? The PRACH Index ensures multiple UEs can simultaneously send access requests without collisions. This is key in high-density areas where many devices are trying to connect at once. 🔸 How Does It Work? 1️⃣ The UE selects a preamble based on available PRACH Indexes. 2️⃣ The eNB receives the request, determines the source, and responds with a random access response (RAR). 3️⃣ The UE then adjusts timing to finalize the connection. 🔸 What Does This Mean for Network Performance? A well-managed PRACH process ensures efficient access, preventing overloads and delays in establishing connections. The PRACH Index makes the process smooth and collision-free, even in high-traffic conditions. 📊 Key Takeaways: PRACH Index helps to manage random access requests efficiently. It ensures proper timing and frequency allocation for each connection attempt. A properly configured PRACH process is critical for network stability in busy environments. By optimizing the PRACH Index settings and configurations, we can improve network performance, reduce RAB failures, and ensure a seamless user experience. How have you optimized the PRACH process in your network? Let’s discuss! 🔍

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🔍 RF Optimization Insight: Don't Overlook TA in Load Balancing! While PRB utilization is a commonly used metric for load balancing in LTE networks, it’s equally important to analyze Timing Advance (TA) distribution. 📶 Why TA Matters? High PRB usage doesn’t always mean true congestion. Sometimes, distant users with high TA values occupy more radio resources due to poor radio conditions. Simply offloading based on PRB can result in ineffective load distribution if TA isn’t considered. ✅ Best Practice: Combine PRB utilization with TA histogram analysis to identify cells with far-away users. Offloading such users to nearby cells (where possible) improves spectral efficiency and real load balancing. 👨‍💻 As RF professionals, it’s our job to ensure intelligent optimization—not just threshold-based actions. #RFOptimization #LTE #LoadBalancing #TAAnalysis #PRBUtilization #NetworkPerformance #RANOptimization #5GReady

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