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EPC EUTRAN LTE Mobile Networks Notes RF

LTE (4G) – TMSI & GUTI

We’ve already touched on how subscribers are authenticated to the network, how the network is authenticated to subscribers and how the key hierarchy works for encryption of user data and control plane data. If the IMSI was broadcast in the clear over the air, anyone listening would have the unique identifier of the subscriber nearby […]

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EPC EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Mobility Management – 3. Processing Location Updates

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. Let’s look at how the Tracking Area Updates work from the point of view of the network. Let’s take an example of a […]

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EPC EUTRAN LTE Notes RF

IMTx: NET02x (4G Network Essentials) – Mobility Management – 4. Changing MME and SGW

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. As we’ve seen earlier, the eNB needs a connection to an MME and a S-GW. However different eNBs may connect to different S-GWs […]

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EPC EUTRAN LTE Notes RF

IMTx: NET02x (4G Network Essentials) – Mobility Management – 2. Balancing Location Update Load

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. As we saw before larger Tracking Areas minimize the number of UEs between terminals to update their location. The problem is the cells/eNBs […]

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EPC EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Mobility Management – 1. Managing Location

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. As we saw with the Network Triggered Service Request, the network needs to know which eNB / cell the UE is currently being […]

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EPC EUTRAN LTE Notes RF

IMTx: NET02x (4G Network Essentials) – Management of Sporadic Data Flows – 3. Standby Modes

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. As we discussed before when no data has been sent by a UE for a period of time the eNB will switch from […]

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EPC EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Management of Sporadic Data Flows – 4. UE Triggered Service Request

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. As we just saw when a terminal moves to ECC-Idle while in EMM-Registered state, it releases it’s radio resources, so what happens when […]

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EPC EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Management of Sporadic Data Flows – 2. UE Connection to the Network

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. One of the common themes we cover over and over in the 4G discussion is the desire to preserve energy on the UE […]

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EPC EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Management of Sporadic Data Flows – 1. Attach and Detach Procedures

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. A LTE UE has permanent IP connectivity for as long as it is connected. As soon as the UE powers up it requests […]

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EPC EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Management of Data Flows – 7. NAS and Global View of Protocol Stack

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. The LTE architecture compartmentalises the roles in the mobile network. For example the eNB concentrates on radio connection management, while the MME focuses […]

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EPC EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Management of Data Flows – 5/6. S1AP Connection

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. Each MME can manage millions of UEs. To handle this load the requirements of each subscriber for the MME must be as minimal […]

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EPC EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Management of Data Flows – 3. Identifying & Managing Tunnels

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. As we’ve talked about traffic to and from UEs is encapsulated in GTP-U tunnels, with the idea that by encapsulating data destined for […]

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EPC EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Management of Data Flows – 2. GTP Protocol

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. When a packet arrives from an external network, like the internet, it is routed to the P-GW. The P-GW takes this packet and […]

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EPC EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Radio Interface – 7. PDCP & Global Vision

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. The Packet Data Convergence Protocol PDCP protocol stack sits ontop of the radio interface stack, and manages the connection the EPC. There is […]

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EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Radio Interface – 6. Random Access

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. LTE mostly relies on reservation based protocols, meaning resources are broken up into smaller elements which are reserved and allocated dynamically as needed. […]

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EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Radio Interface – 5. RLC Protocol

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. As we just discussed the MAC layer multiplexes streams from the RLC layer. This allows mutliple streams of data to share the same […]

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EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Radio Interface – 4. Transmission Reliability in Radio

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. Radio is always subject to interference, we talked before about how coding is used on the physical layer to try and correct these […]

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EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Radio Interface – 3. Packet Allocation

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. Allocation Tables To inform UEs of which resources are allocated to it, the eNB regularly publishes Allocation Tables with this information. Resources are […]

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EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Radio Interface – 2. Resource Blocks & Sub-Frames

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. As spectrum is sparse and expensive, so it must be used wisely and shared across multiple users. LTE shares spectrum in both frequency […]

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EUTRAN LTE Mobile Networks Notes RF

IMTx: NET02x (4G Network Essentials) – Radio Interface – 1. Radio Transmission

These are my lecture notes from IMT’s NET02x (4G Network Essentials) course, I thought I’d post them here as they may be useful to someone. You can find my complete notes here. The E-UTRAN relies on Phase Shift Keying to modulate data. The downlink uses orthogonal frequency division multiplex (OFDM) while the uplink uses SC-FDMA […]