Categories
GSM IMS / VoLTE Mobile Networks VoIP

Sending SMS with an alphanumeric String as the Source

If you’ve ever received an SMS from your operator, and the sender was the Operator name for example, you may be left wondering how it’s done. In IMS you’d think this could be quite simple – You’d set the From header to be the name rather than the MSISDN, but for most SMSoIP deployments, the […]

Categories
GSM Mobile Networks SDM Software

USSD Gateway with Osmocom

Unstructured Supplementary Service Data or “USSD” is the stack used in Cellular Networks to offer interactive text based menus and systems to Subscribers. If you remember topping up your mobile phone credit via a text menu on your flip phone, there’s a good chance that was USSD*. For a period, USSD Services provided Sporting Scores, […]

Categories
Mobile Networks RFCs & Standards VoIP

Demystifying SS7 & Sigtran (With Labs!) – Part 2 – Ingredients Needed

Looking at the basic components that make up our SS7 Networks.

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Mobile Networks RFCs & Standards VoIP

Demystifying SS7 & Sigtran Networks (With Labs!) – Part 1 – Intro

Taking a look at the basics of the SS7 Protocol Stack.

Categories
GSM LTE Mobile Networks RFCs & Standards

Looking inside the MMS Exchange (With call flow and PCAP)

A look at Multimedia Messaging (MMS) in 3GPP Networks and how it actually works.

Categories
5G SA EPC EUTRAN GSM LTE Mobile Networks RFCs & Standards

Pre-5G Network Slicing

5G introduces Network Slicing, or does it? A look at slicing mechanisms widely used in pre-5G networks.

Categories
GSM Mobile Networks

GSM with Osmocom: OsmoSGSN for Packet Data

Configuring the Osmocom Serving Gateway Support Node (SGSN) for 2G/3G networks.

Categories
GSM Mobile Networks RF

Using a NanoVNA to analyse SDR Base Station Antennas

Using a NanoVNA to analyse antenna performance for SDR driven Base Stations for GSM / LTE.

Categories
GSM Mobile Networks

Twenty years of the Nokia 3310

1 September 2000 was when the 3310 was released…

Categories
GSM Mobile Networks RF

GSM with Osmocom: Handovers

A look at the Handover process between Cells / BTSs in GSM using the Osmocom stack.

Categories
GSM Mobile Networks RF

GSM with Osmocom: Channel Types

When setting up the timeslots on the TRX for each BTS on your BSC, you’ll notice you have to set a channel type. So what do these acronyms mean, and how do they affect the performance of the network? GSM channels break down into one of to categories, control channels – used for signalling, and […]

Categories
GSM Mobile Networks

GSM with Osmocom: Silent SMS & Silent Calls

Depending on if you’re wearing a tin foil hat or not, silent SMS and silent calls could be a useful tool to for administering the network or a backdoor put in to track citizenry! Regardless of it’s reasons for existence, let’s take a look at what it actually does, and how we can use it. […]

Categories
GSM Mobile Networks RF

GSM with Osmocom: GPRS & Packet Data

So far we’ve focused on building a plain “2G” (voice and SMS only) network, which was all consumers expected twenty years ago. As the number of users accessing the internet through DSL, Dial Up & ISDN grew, the idea of getting this data “on the go” became more appealing. TCP/IP was becoming the dominant standard […]

Categories
GSM Mobile Networks

GSM with Osmocom: SS7 & Sigtran

SS7 Basics and Osmo-STP as a Signaling Transfer Point

Categories
GSM Mobile Networks

GSM with Osmocom: NanoBTS

Setting up ipaccess NanoBTS on Osmocom’s OsmoBSC

Categories
EPC EUTRAN GSM IMS / VoLTE LTE Mobile Networks

Sending SMS in Open5GS LTE Networks using the SGs Interface and OsmoMSC with SMSoS

Sending SMS over LTE using OsmoMSC and OsmoHLR and the SGs interface for SMSoS

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EPC EUTRAN GSM LTE Mobile Networks

OsmoMSC and Open5GS MME – SGs Interface for InterRAT Handover & SMS

Looking into the SGi interface for Circuit Switched Fallback in LTE to use GSM/UMTS networks for Calls & SMS

Categories
GSM IMS / VoLTE Mobile Networks VoIP

GSM with Osmocom: Call routing in GSM

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

Categories
GSM IMS / VoLTE 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 […]

Categories
GSM Mobile Networks

GSM with Osmocom Part 8: The Mobile Switching Center

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