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GSM Mobile Networks

GSM with Osmocom: SS7 & Sigtran

SS7 Basics and Osmo-STP as a Signaling Transfer Point

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GSM Mobile Networks

GSM with Osmocom: NanoBTS

Setting up ipaccess NanoBTS on Osmocom’s OsmoBSC

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GSM Mobile Networks Voice over IP

GSM with Osmocom: Call routing in GSM

How call routing in GSM works and it’s application in the Osmocom suite

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GSM Mobile Networks RF

GSM with Osmocom Part 9: Calls & SMS at last!

So now we’ve covered the basics of what’s involved let’s get some traffic on our network. For starters we’ll need to start each of our network elements and bring up whichever BTS hardware we’re using. In order for our calls to have audio, we’ll need to set a parameter on the Media Gateway. We’ll cover […]

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GSM Mobile Networks

GSM with Osmocom Part 8: The Mobile Switching Center

Setting up the Mobile Switching Centre for a GSM network using OsmoMSC.

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GSM Mobile Networks

GSM with Osmocom Part 7: The HLR – Home Location Register (and Friends)

What the Home Location Register (HLR) does in GSM, how to set it up and configure subscribers.

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GSM Mobile Networks

GSM with Osmocom Part 6: Integrating our LimeSDR BTS with OsmoBSC

Connecting our LimeSDR based GSM BTS with OsmoBSC.

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GSM Mobile Networks

GSM with Osmocom Part 5: Software BTS with LimeSDR & osmo-bts-trx

Using a LimeSDR as a GSM BTS with Osmocom.

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GSM Mobile Networks

GSM with Osmocom Part 4: The Base Station Controller (BSC)

Configuring a GSM Base Station Controller with Osmocom stack.

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GSM Mobile Networks

GSM with Osmocom Part 3: Introduction to Osmo Software & Virtual BTS

Setting up a virtual BTS in our BSC with Osmocom.

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GSM Mobile Networks

GSM with Osmocom Part 2: BTS Basics

What’s a BTS and where do they fit into the GSM Network architecture?

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GSM Mobile Networks

GSM with Osmocom Part 1: Intro

Intro to our post series on GSM using the Osmocom stack,

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EPC EUTRAN LTE Mobile Networks Security

Roll your own USIMs for Private LTE Networks

Adventures in getting USIMs to use on private LTE networks.

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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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LTE Mobile Networks RF RFCs & Standards Security

LTE (4G) – EUTRAN – Key Distribution and Hierarchy

We’ve talked a bit in the past few posts about keys, K and all it’s derivatives, such as Kenc, Kint, etc. Each of these is derived from our single secret key K, known only to the HSS and the USIM. To minimise the load on the HSS, the HSS transfers some of the key management […]

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LTE Mobile Networks RF RFCs & Standards Security

LTE (4G) – Ciphering & Integrity of Messages

We’ve already touched on how subscribers are authenticated to the network, how the network is authenticated to subscribers. Those functions are done “in the clear” meaning anyone listening can get a copy of the data transmitted, and responses could be spoofed or faked. To prevent this, we want to ensure the data is ciphered (encrypted) […]

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EPC LTE Mobile Networks RF RFCs & Standards Security

LTE (4G) – Authenticating the Network

How LTE Subscriber authenticate the network

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EPC LTE Mobile Networks RF RFCs & Standards

LTE (4G) – Authenticating Subscribers

LTE/4G’s use of RAND and K to verify subscribers identity.

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LTE Mobile Networks RF RFCs & Standards Security

LTE (4G) – USIM Basics

Contents of a USIM, fields & their meanings and basics of EUTRAN authentication.

Categories
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 […]