Mobile Network Architecture: 4G vs 5G on Data Communications and Networking

Mobile networks have revolutionized how we communicate and access information in our increasingly connected world. As we’ve transitioned from 4G to 5G technologies, significant architectural changes have occurred that impact data communications and networking capabilities. This article explores the fundamental differences between 4G and 5G network architectures and examines how these differences affect data communications performance, reliability, and applications.

Understanding Mobile Network Generations

Before diving into the specific architectural components, let’s establish some context about network generations. Each generation of mobile technology represents a significant leap in capabilities:

• 1G: Introduced analog voice calls in the 1980s
• 2G: Added digital voice and basic data services (SMS, MMS) in the 1990s
• 3G: Enabled mobile internet access and video calling in the early 2000s
• 4G: Delivered high-speed mobile broadband for streaming and advanced applications in the 2010s
• 5G: Offers ultra-high speeds, massive connectivity, and ultra-low latency starting in the late 2010s

4G LTE Network Architecture

4G LTE (Long-Term Evolution) represented a significant advancement over 3G networks through its all-IP packet-switched architecture. The core components of 4G architecture include:

Radio Access Network (RAN)

In 4G, the RAN consists primarily of:

• eNodeB (evolved Node B): The base stations that connect directly to mobile devices and handle radio communications
• X2 Interface: Direct connections between eNodeBs for handover management and interference coordination

Core Network (Evolved Packet Core - EPC)

The 4G core network consists of:

• MME (Mobility Management Entity): Handles signaling related to mobility and security
• S-GW (Serving Gateway): Routes and forwards user data packets
• P-GW (Packet Data Network Gateway): Provides connectivity to external networks like the internet
• HSS (Home Subscriber Server): A database containing user-related information

Key Characteristics of 4G Architecture

• Relatively flat architecture compared to 3G
• All-IP based network
• Theoretical peak download speeds of 100 Mbps (practical speeds: 20-50 Mbps)
• Latency of 50-100 milliseconds
• Connection density of about 2,000 devices per square kilometer
• Primarily designed for mobile broadband applications

5G Network Architecture

5G represents not just an incremental improvement but a fundamental redesign of mobile network architecture to support vastly different use cases.

Radio Access Network (5G NR)

The 5G New Radio (NR) access network features:

• gNodeB (next-generation Node B): Advanced base stations supporting wider frequency ranges
• Massive MIMO (Multiple Input Multiple Output): Using many more antennas to improve throughput and efficiency
• Beamforming: Directing radio signals precisely toward devices rather than broadcasting widely
• Millimeter Wave (mmWave) Support: Using higher frequency bands (24-100 GHz) for extremely high data rates

Core Network (5G Core)

The 5G core network is built on a service-based architecture (SBA) with modular network functions:

• AMF (Access and Mobility Management Function): Handles connection and mobility management
• SMF (Session Management Function): Manages session establishment and data routing
• UPF (User Plane Function): Handles packet processing and traffic routing
• NRF (Network Repository Function): Maintains available network function services
• NSSF (Network Slice Selection Function): Manages network slicing
• UDM (Unified Data Management): Stores subscriber data and profiles

Network Slicing

One of the most revolutionary aspects of 5G architecture is network slicing - the ability to create multiple virtual networks on top of a common physical infrastructure. Each slice can be optimized for specific applications:

• eMBB (enhanced Mobile Broadband): For high-speed data services
• URLLC (Ultra-Reliable Low-Latency Communications): For applications requiring instantaneous response
• mMTC (massive Machine Type Communications): For IoT and connected device applications

Key Characteristics of 5G Architecture

• Service-based, cloud-native architecture
• Theoretical peak download speeds of 10 Gbps (practical speeds: 100-900 Mbps)
• Ultra-low latency of 1-10 milliseconds
• Connection density of up to 1 million devices per square kilometer
• Support for diverse use cases through network slicing

Architectural Differences: 4G vs 5G

Several fundamental architectural differences separate 4G and 5G networks:

1. From Hardware to Software

While 4G networks rely heavily on dedicated hardware components, 5G employs concepts like Network Function Virtualization (NFV) and Software-Defined Networking (SDN):

4G Approach:

• Primarily hardware-based network functions
• Limited flexibility for scaling or upgrading
• Longer deployment times for new services

5G Approach:

• Virtualized network functions running on standard servers
• Cloud-native architecture with containerization
• Dynamic scaling and resource allocation
• Faster deployment of new services through software updates

For system administrators, this shift means managing more software components and cloud resources rather than dedicated hardware appliances.

2. Control and User Plane Separation (CUPS)

4G began implementing some separation between control plane (signaling) and user plane (data), but 5G takes this concept much further:

4G Implementation:

• Partial separation with some functions still handling both planes
• Limited flexibility in routing and scaling

5G Implementation:

• Complete separation of control and user planes
• Independent scaling of signaling and data functions
• Optimized routing paths for data traffic
• Lower latency through more efficient data handling

This separation allows network operators to place user plane functions closer to the network edge, reducing latency for data-intensive applications.

3. Edge Computing Integration

Edge computing moves processing closer to data sources rather than relying on centralized data centers:

4G Approach:

• Limited edge computing capabilities
• Most processing happens in centralized locations
• Higher latency for compute-intensive applications

5G Approach:

• Multi-access Edge Computing (MEC) built into the architecture
• Processing capabilities distributed throughout the network
• Compute resources placed at or near base stations
• Dramatically reduced latency for applications like AR/VR, autonomous vehicles

For developers, this means applications can leverage local processing power without sending data to distant cloud servers.

Impact on Data Communications

These architectural differences significantly impact data communications in several key ways:

Throughput and Capacity

4G networks typically offer real-world download speeds of 20-50 Mbps, with theoretical maximums around 100 Mbps. In contrast, 5G can deliver 100-900 Mbps in typical deployments, with theoretical peaks of 10 Gbps or more.

This increase results from:

• Wider frequency bands (especially in mmWave spectrum)
• More efficient spectrum use through advanced modulation techniques
• Massive MIMO technology using dozens of antennas simultaneously
• Better beamforming to focus signals where needed

For users, this means downloading a 4K movie in seconds rather than minutes, streaming multiple high-definition video feeds simultaneously, and supporting bandwidth-intensive applications like virtual reality.

Latency Reduction

Perhaps even more significant than speed improvements is 5G’s dramatic reduction in latency:

4G Latency: 50-100 milliseconds 5G Latency: As low as 1-10 milliseconds

This improvement comes from:

• Simplified core network architecture
• Edge computing integration
• More efficient packet processing
• Shorter transmission time intervals (TTI)

Low latency enables entirely new classes of applications like:

• Real-time remote surgery
• Vehicle-to-everything (V2X) communications for autonomous driving
• Tactile internet applications with immediate feedback
• Real-time industrial automation

Connection Density

4G networks can typically support about 2,000 connected devices per square kilometer. 5G increases this capacity to nearly 1 million devices per square kilometer—a 500x improvement.

This massive increase enables:

• True smart city deployments with millions of sensors
• Industrial IoT implementations with dense sensor networks
• Venue-specific networks handling tens of thousands of simultaneous connections
• Smart agriculture with field-wide sensor coverage

Network Protocols and Interfaces

The evolution from 4G to 5G has also brought significant changes to the protocols and interfaces used within the network:

Protocol Evolution

4G Protocols:

• GTP (GPRS Tunneling Protocol) for user data transport
• Diameter protocol for AAA (Authentication, Authorization, Accounting)
• S1-AP for communication between eNodeB and MME

5G Protocols:

• HTTP/2 and JSON for service-based interfaces in the core
• PFCP (Packet Forwarding Control Protocol) replacing GTP control plane
• NGAP (Next Generation Application Protocol) for gNodeB to AMF communication

For network engineers, this shift toward web-based protocols makes 5G networks more compatible with existing internet infrastructure and development tools.

API-Based Interfaces

Perhaps the most significant protocol change is 5G’s move toward API-based interfaces between network functions:

4G Approach:

• Point-to-point interfaces between specific network elements
• Custom protocols for different interfaces
• Relatively rigid interconnections

5G Approach:

• Service-based interfaces using standard RESTful APIs
• Network functions register their services with the NRF
• More flexible discovery and consumption of network services
• Easier integration with external applications and services

This API-first approach makes 5G networks more programmable and adaptable, enabling faster development cycles for new services.

Security Implications

Security architectures have also evolved significantly between generations:

4G Security:

• Authentication primarily between device and network
• Limited encryption options
• Relatively centralized security functions

5G Security:

• Enhanced subscriber privacy protection
• More comprehensive encryption throughout the network
• Network slice isolation for security compartmentalization
• Zero-trust architecture principles
• Distributed security functions

For security professionals, 5G requires a more comprehensive approach to security with protection at multiple layers of the network stack.

Implementation Challenges

The transition from 4G to 5G architecture presents several challenges for operators and technical teams:

1. Infrastructure Investment: Deploying dense small cell networks and fiber backhaul requires significant capital expenditure
2. Spectrum Allocation: Securing sufficient spectrum across low, mid, and high bands
3. Backward Compatibility: Maintaining seamless service for 4G devices during transition
4. Skills Gap: Training technical teams on new virtualized, cloud-native technologies
5. Security Complexity: Managing security across a more distributed architecture

Conclusion

The evolution from 4G to 5G represents far more than just faster speeds—it embodies a fundamental rethinking of mobile network architecture. By embracing virtualization, edge computing, network slicing, and service-based designs, 5G networks can simultaneously support diverse use cases with widely different requirements.

As these networks continue to deploy globally, we’ll see increasing innovation in applications that leverage these architectural advantages. For network professionals, understanding these architectural shifts is essential for designing, deploying, and managing the next generation of mobile communications systems. For developers and businesses, these architecture changes open new possibilities for applications that were previously impossible on mobile networks.

The transition won’t happen overnight—4G and 5G will coexist for many years, with 5G initially focusing on capacity relief in dense areas and specific use cases that benefit most from its architectural advantages. Over time, as coverage expands and the ecosystem matures, we’ll see more applications fully leveraging 5G’s architectural benefits across all sectors of the economy.