GSM vs. LTE: A Detailed Comparison of Cellular Technologies

This article provides a comprehensive comparison between GSM (Global System for Mobile Communication) and LTE (Long Term Evolution), two prominent cellular wireless technologies. Understanding the differences between these technologies is crucial in the context of modern telecommunications.

GSM vs. LTE: Key Differences

The following table summarizes the key specifications and differences between GSM and LTE:

Feature	GSM	LTE
Full Form	Global System for Mobile Communication	Long Term Evolution
Frequency Band (MHz)	GSM850, GSM900, DCS1800, PCS1900	LTE supports frequency Band 1 to 25, band 33 to band 43.
Channel Bandwidth	200KHz	Release 8 supports 1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz, and 20MHz
Access Scheme	FDMA/TDMA	OFDMA (Downlink), SC-FDMA (Uplink)
Topology	FDD (Frequency Division Duplex)	TDD (Time Division Duplex) and FDD
Frame Structure	Two types: 26-frame MF (120ms, traffic) and 51-frame MF (235.4ms, control)	Supports TDD and FDD frame structures, 10ms total frame duration
Modulation Method	GMSK	QPSK, 16QAM, 64QAM
Physical Layer	GSM Physical layer composed of modules which include forward error correction ,interleaving,ciphering, burst building,multiplexing, differential encoding, GMSK modulation etc. It is same on both base station and subscriber station side.	Different for both the UE and eNodeB, UE uses SC-FDMA in the transmit while eNodeB uses OFDMA in the transmit side.
Channel Number	ARFCN (Absolute Radio Frequency Channel Number)	EARFCN (E-UTRA Absolute Radio Frequency Channel Number)
Protocol Stack	PHY, LAPDm, RRM, MM, CM layers at Mobile Subscriber (MS).	PHY, MAC, RLC, PDCP, RRC.
Channel Types	Logical and Physical Channels.	Logical, Physical, and Transport Channels.
Network Architecture
Application	Mainly for voice calls, GPRS/EGPRS needed for data calls	Mainly for data calls
Advanced Features	Supports GSM advanced features such as MUROS, VAMOS, SAIC, MSRD	LTE Advanced (Release-10) supports MIMO, beamforming, Carrier Aggregation, etc.
Cell Search Procedure
MIMO Support	GSM advanced supports 2x2 MIMO	LTE Advanced supports 4x4 and 8x8 MIMO, supports multi-user and co-operative MIMO
Security Aspects	Uses A3, A5, and A8 algorithms for encryption.	Five LTE security groups described in 3GPP 33.401 document
UE Categories	Supports different categories for multislot configuration mainly to provide GPRS support
Throughput
Modulation Efficiency	1.35 b/s/Hz	Downlink cell: 1.69 bps/Hz/user (2x2 MIMO), 2.67 (4x4 MIMO - LTE Standard), 2.4 and 3.7 respectively for LTE-Advanced standard
Timers
Measurements

Key Takeaways

• Purpose: GSM primarily focused on voice communication, while LTE is designed for high-speed data transmission.
• Efficiency: LTE offers significantly higher spectral efficiency and throughput compared to GSM.
• Advanced Features: LTE supports advanced features like MIMO and carrier aggregation, leading to improved performance.
• Network Architecture: The network architectures of GSM and LTE differ substantially to accommodate their respective functionalities.
• Security: Both technologies employ security mechanisms, but LTE uses more advanced security protocols.

By understanding these differences, you can gain a clearer perspective on the evolution of cellular wireless technologies and the advantages of LTE over GSM in modern communication systems.