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Overview
GSM remains one of the most widely deployed cellular technologies for machine-to-machine and industrial applications. SNYPER products can detect and analyse GSM, GPRS and EDGE networks, reporting a range of identifiers and signal measurements that help users assess network availability and suitability. This guide explains the terminology commonly encountered during GSM surveys.
2G Network Retirement (GSM EoL Sunset)
GSM (2G) networks have been retired in many countries and continue to be phased out globally. Existing deployments should be reviewed and migration to LTE, LTE-M, NB-IoT or 5G technologies should be considered where appropriate.
| Product | Description |
|---|---|
| SNYPER-5G Graphyte | 5G, LTE, LTE-M, NB-IoT and GSM cellular network analyser. |
| SNYPER-LTE Graphyte | LTE and legacy cellular analyser. |
| Legacy SNYPER Products | GSM, GPRS and EDGE survey capable analysers. |
| SENTRY Network Analysers | Embedded cellular monitoring products. |
| CloudSURVEY | Cellular survey visualisation platform. |
This guide explains:
Expected Result
At the end of this guide the user will understand the identifiers and measurements reported during GSM surveys.
GSM (Global System for Mobile Communications) is a second-generation cellular technology originally developed for voice communications and low-speed data services.
Although many operators are retiring GSM infrastructure, it remains operational in numerous regions and continues to support many industrial and machine-to-machine deployments.
Modern GSM networks can support:
The widespread deployment and long-range coverage characteristics of GSM have made it popular for telemetry, asset tracking and remote monitoring applications.
General Packet Radio Service (GPRS) provides packet-switched data communications over a GSM network.
| Service | Typical Throughput |
|---|---|
| GSM CSD | Up to 9.6 kbps |
| GPRS | Up to 80 kbps |
| EDGE | Up to 236 kbps |
Enhanced Data Rates for GSM Evolution (EDGE) improves packet data performance through more efficient radio modulation techniques.
The Mobile Country Code identifies the country associated with the cellular network.
| MCC | Country |
|---|---|
| 234 | United Kingdom |
| 262 | Germany |
| 208 | France |
| 310 | United States |
The MCC allows survey data to be associated with a specific country and forms part of the PLMN identifier.
The Mobile Network Code identifies the operator within a specific country.
| MCC | MNC | Operator |
|---|---|---|
| 234 | 15 | Vodafone UK |
| 234 | 30 | EE |
| 234 | 10 | O2 |
The MNC allows identification of the specific network operator providing service.
The Location Area Code identifies a geographical service region within a GSM network.
The network uses LAC values for:
Changes in LAC values often indicate movement between network service regions.
The Cell ID uniquely identifies an individual GSM serving cell.
| Parameter | Example |
|---|---|
| Cell ID | 12345 |
| LAC | 321 |
| Operator | Vodafone |
Cell IDs support:
ARFCN identifies the specific GSM radio carrier frequency used by the serving cell.
| ARFCN | Band |
|---|---|
| 62 | GSM 900 |
| 700 | DCS 1800 |
ARFCN identifies:
| Band | Frequency Range | Typical Characteristics |
|---|---|---|
| GSM 850 | 850 MHz | Excellent range and penetration |
| GSM 900 | 900 MHz | Excellent coverage characteristics |
| DCS 1800 | 1800 MHz | Higher capacity and urban deployment |
| PCS 1900 | 1900 MHz | Higher capacity deployment |
The Base Station Identity Code uniquely identifies a GSM radio transmitter.
BSIC consists of:
BSIC assists devices in distinguishing neighbouring cells operating on similar frequencies and reduces the likelihood of incorrect cell identification.
Received Signal Level (RxLev) represents the strength of the received GSM signal.
Higher RxLev values generally indicate stronger received signal strength and improved coverage conditions.
| GSM RxLev Signal Strength Scale | |||
| Poor | Fair | Good | Excellent |
| 0–19 | 20–34 | 35–49 | 50–63 |
Signal strength may also be displayed using dBm values.
Signal strength directly influences coverage reliability, device registration and service continuity.
| GSM Signal Strength Scale (dBm) | ||||
| Very Weak | Weak | Fair | Good | Excellent |
| < -105 dBm | -105 to -95 dBm | -95 to -85 dBm | -85 to -75 dBm | > -75 dBm |
Timing Advance represents the propagation delay between a mobile device and the serving GSM base station.
| Timing Advance | Approximate Distance |
|---|---|
| 0 | Very close to the serving cell |
| 1 | ~550 m |
| 10 | ~5.5 km |
| 20 | ~11 km |
| 35 | ~19 km |
Timing Advance provides an estimate of relative distance from the serving cell.
Important Note
Timing Advance values provide an indication only and should not be considered an exact distance measurement.
C1 is a GSM cell selection parameter used to determine whether a cell is suitable for service.
C1 is used during:
Higher C1 values generally indicate a more desirable serving cell.
C2 is an enhanced cell reselection parameter used when evaluating neighbouring cells.
C2 allows the network to influence:
Cells with better C2 values may be preferred even when raw signal strength is slightly lower.
GSM devices continually evaluate neighbouring cells to maintain service continuity.
Important parameters include:
Together these measurements influence:
Characteristics typically include:
Characteristics typically include:
Characteristics typically include:
| Observation | Possible Cause | Recommendation |
|---|---|---|
| Low RxLev | Weak coverage | Improve antenna placement. |
| High Timing Advance | Distant base station | Consider a higher gain antenna. |
| Frequent Cell Changes | Overlapping coverage | Review installation location. |
| Poor GPRS Performance | Congested network | Compare alternative operators. |
| Missing Expected Network | Coverage limitation | Re-survey from an alternative location. |
| Parameter | Purpose |
|---|---|
| MCC | Country identification. |
| MNC | Operator identification. |
| LAC | Location area identification. |
| Cell ID | Cell identification. |
| ARFCN | Frequency identification. |
| BSIC | Base station identification. |
| RxLev | Signal strength indication. |
| C1 | Cell selection metric. |
| C2 | Cell reselection metric. |
| Timing Advance | Relative distance estimation. |
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