Signalling in GSM BSS

"Signalling in GSM BSS" course focuses on signalling between GSM nodes within Base Station System (BSS). During the course all protocols and signalling procedures on all interfaces within BSS are presented in details. The organisation of channels of air interface and cell parameters is also widely covered in the course. The course also describes parts of the Signalling System No. 7 that are relevant for BSS and presents co-operation between Core Network and BSS during procedures like call set-up and location update.

Target audience

The course is intended for experienced network engineers and network tuning staff and anyone with network experience, who needs deep technical knowledge on functionality of GSM BSS.

Training contents

  • Introduction
    (GSM architecture, GSM architecture for SMS, data and fax services, mobile intelligent network, GSM identity numbers, types of signalling, GSM protocol stack),
  • Physical and logical channels
    (GSM frequency bands, FDMA and radio channels, TDMA and physical channels, frequency hopping, logical channels, permitted channel combinations, mapping, timeslot structure),
  • Traffic Cases
    (radio connection establishment, location updating, IMSI detach, MO - Mobile Originating and MT - Mobile Terminating call, handover),
  • Um interface
    • Layer 3
      (CM - Connection Management, MM - Mobility Management and RR - Radio Resource Management, CM protocols: CC - Call Control, SS - Supplementary Services and SMS, procedure examples: MO/MT call set-up, call clearing, call mode change, CCBS - Call Completion to Busy Subscriber, call hold/retrieve, call waiting, multiparty call, DTMF, security procedures, location update and IMSI detach, radio link establishment and release, handover),
    • Layer 2 - LAPDm
      (frame structure, acknowledge/unacknowledged mode, retransmissions, segmentation),
    • Layer 1 - physical layer
      (channel coding, burst formatting, modulation).
  • Speech processing
    (speech compression, channel coding, DTX - Discontinuous Transmission, VAD - Voice Activity Detection, lost frame substitution, AMR - Adaptive Multi Rate),
  • MS in idle and active state
    (system information messages, PLMN selection, cell selection and reselection, radio link measurements),
  • A-bis interface
    • BTSM - BTS Management protocol
      (radio link layer, dedicated channel, common channel and TRX management procedures, message structure).
    • LAPD
    • Physical layer
  • SS7 overview and SS7 in BSS
    (network components, protocol stack, MTP - Message Transfer Part, SCCP - Signalling Connection Control Part, usage of SCCP connection oriented mode on A interface, BSSAP - Base Station System Application Part: BSSMAP - BSS Management Application Part, handling of non-transparent and initial MS messages, TCH assignment, handover),
  • MSC in pool
    (MSC in pool concept, Network Resource Identification, node selection, NRI based routing, load balancing and redistribution, MM procedures).


The participants should have attended "GSM Technology" course or should have the equivalent knowledge. Practical experience in GSM would be recommended.

Training method

Lectures and theoretical exercises.


4 days