USSD Over IMS: How USSD Services Work on 4G and 5G Networks

USSD has long been associated with 2G and 3G networks, but it still has an important role as mobile operators move toward 4G and 5G. Mobile banking, mobile money, balance checks, prepaid services, account management, and enterprise applications continue to rely on simple, session-based interactions. The main change is how those services connect to the network. For operators evaluating a USSD Service Provider, support for USSD over IMS is becoming increasingly important.

hSenid’s USSD platform supports 2G, 3G, 4G, and 5G through a single application server. This allows operators to maintain USSD services across different network generations without managing completely separate application environments.

Why USSD Needs a New Approach on 4G and 5G

Traditional USSD services were designed around circuit-switched mobile networks. As operators move toward LTE and 5G, communication increasingly relies on IP-based architecture and the IP Multimedia Subsystem, or IMS.

That does not mean USSD must disappear.

Instead, the network integration method changes. With USSD over IMS, operators can continue offering familiar short-code services while connecting those services to modern mobile cores.

A subscriber can still dial a short code, follow menu options, select a service, and receive a response. Behind that interaction, the USSD platform manages signaling, session control, and communication with the IMS network.

hSenid’s architecture includes an IMS-ready SIP connector for core network integration. It also supports SIGTRAN-based connectivity for traditional networks. This gives operators flexibility to support both older and newer mobile environments.

How USSD Over IMS Works

When a subscriber starts a USSD session on a supported 4G or 5G network, the request can be handled through the IMS core instead of depending only on circuit-switched infrastructure.

The USSD gateway receives the request and identifies the relevant application. It then maintains the subscriber session, communicates with the service application, and sends the response back through the network.

The interaction remains simple from the subscriber’s perspective.

hSenid’s USSD platform integrates with the core network’s IMS using SIP and XML payloads. According to the product documentation, the solution is built in accordance with the 3GPP TS 24.390 specification.

For a telecom operator or USSD Service Provider, this creates a practical migration path. Existing USSD services can continue while the underlying network evolves.

Reliable USSD Session Management Matters

USSD is interactive by nature.

A customer may check a balance, enter a PIN, select a payment option, confirm a transaction, and receive a result within one session. That makes USSD session management essential.

The gateway needs to handle session initiation, continuation, and termination correctly.

hSenid’s USSD Gateway manages sessions for each USSD application and also provides session-resuming capability. If an unexpected timeout occurs within a defined period, the user can be directed back to the most recent menu instead of restarting the interaction from the beginning.

This is especially useful for financial and transactional services where interruptions can create frustration or increase failed transactions.

USSD for Mobile Money and Fintech Services

A USSD gateway for mobile money allows subscribers to access wallets, financial platforms, payment services, and other backend systems without downloading an application.

This remains valuable in markets where smartphone adoption and mobile data access vary significantly.

The hSenid USSD use case shows how organizations can deliver app-like digital services on basic mobile phones without requiring internet access, downloads, or a data plan. Users can dial a short code, follow menu options, and complete transactions through a familiar interface.

For organizations looking for the Best USSD provider for fintech, integration flexibility is just as important as network support.

A modern USSD gateway may need to connect with mobile wallets, payment systems, subscriber databases, charging platforms, CRM systems, and third-party applications.

hSenid’s USSD Gateway exposes REST APIs that allow external applications offering USSD services to connect to an operator’s network. This can reduce implementation complexity and support faster service launches.

USSD Billing Integration in Modern Networks

Moving USSD services to newer network environments does not remove the commercial requirements behind them.

Operators may still need USSD billing integration for premium services, subscriptions, mobile money transactions, or other chargeable interactions.

The platform must therefore work with existing operator charging systems while supporting different charging approaches.

hSenid’s USSD Gateway supports both request-based and session-based charging. It is also designed to integrate with an operator’s existing charging infrastructure.

This flexibility helps operators maintain existing commercial models while modernizing the network architecture underneath them.

Why USSD Still Matters in Africa

For a USSD service provider in Africa, accessibility remains one of the strongest reasons to continue investing in USSD.

Not every subscriber relies on mobile apps for financial or digital services. Some users have basic phones. Others may have limited or inconsistent data connectivity.

USSD provides a direct access channel without requiring users to install software or maintain an active data connection.

The attached hSenid case study describes a banking deployment in the Democratic Republic of Congo where a USSD-based application was used to extend digital banking services nationwide. The service enabled activities such as balance checks, money transfers, bill payments, wallet access, and session recovery.

That example shows why USSD remains relevant even as mobile networks become more advanced.

One Platform Across 2G, 3G, 4G and 5G

Network modernization does not happen at the same speed everywhere.

Many mobile operators continue to support several generations of network technology at the same time. A customer may be connected through 2G in one area and 4G or 5G somewhere else.

A USSD Service Provider therefore needs to support existing subscribers while preparing operators for future network evolution.

hSenid’s USSD service management platform supports 2G, 3G, 4G, and 5G within a single application server. It also combines core network integration, USSD application capabilities, and menu management as part of the wider platform.

This helps operators modernize without replacing every existing USSD service simply because the network architecture is changing.

Modernizing the USSD Experience

Network support is only one part of the evolution.

Modern USSD platforms can also improve how services are created and managed.

hSenid’s platform includes a menu designer and framework that allow operators to create, maintain, approve, and version USSD menus. Dynamic menu capabilities can also change available options based on conditions such as tariff plans, class of service, or subscriber balance.

The product roadmap also includes support for 4G and 5G networks, modernized menu management, improved monitoring, wallet integrations, and intelligent menu capabilities.

For operators, this means USSD can continue evolving rather than remaining a legacy-only channel.

USSD Still Has a Role in the 5G Era

5G changes the mobile network, but it does not automatically change how every subscriber wants to access essential services.

Short-code interactions are still useful because they are simple, familiar, and accessible across a wide range of devices.

Choosing the right USSD Service Provider therefore requires more than checking basic USSD connectivity. Operators should consider IMS readiness, USSD session management, charging flexibility, third-party integrations, application management, and support across multiple network generations.

USSD over IMS provides a practical bridge between familiar subscriber experiences and the IP-based mobile networks being built for the future.