Ditch the Online Charging System

YateUCN removes the need for an Online Charging System for new LTE operators by providing a minimum Guaranteed Bit Rate (GBR) for all subscribers.

In a typical mobile network, the Online Charging System (OCS) sets a maximum allowed bit rate based on available credit to prevent high demand users from congesting the network. The OCS needs to keep track of all the pre-paid accounts of an operator’s subscribers, making it complicated and expensive.

The YateUCN EPC is the alternative that lets the operators set a minimum GBR on the default bearer. This way, it ensures that the network is usable for everyone, even in congested cells, eliminating the need for the OCS.

How it works

YateUCN, through its MME/PGW nodes, allows operators to set a Guaranteed Bit Rate for the default bearer of an UE, so the bandwidth is divided fairly to the connected subscribers supported by the same eNodeB.

Though unusual, this feature works because the eNodeB does not care which bearer is the default bearer, and the UE follows whatever bandwidth scheduling it is given by the eNodeB.

guaranteed_bit_rate_blog

The Guaranteed Bit Rate is set in the MME/PGW components of the YateUCN EPC server though a JSON API. The bit rate is then implemented by the eNodeb.

The Guaranteed Bit Rate works for local data traffic, but not for data roaming, so it is a great solution for former ISP or cable operators switching to LTE, whose main customers are fixed, non-roaming subscribers.

A few final words

Small LTE operators, former ISP or cable operators or operators switching from WiMAX to LTE, have to deal with a lot of hurdles when installing their network. The Online Charging System is one they can forget about. YateUCN allows operators to lower their CAPEX without making any changes to their OPEX, while ensuring that their subscribers have continuous access to the data network.

Busy 2016 for Yate SDMN products

Stepping into 2016, we have exciting news.

Through 2015 we continued to develop the GSM/GPRS SatSite base station, as well as our main core network products: the 2G/2.5G/4G YateUCN core network and the 2G/3G/4G YateHSS/HLR.

We start 2016 with the release of the LTE SatSite Model 142, with software-selectable LTE or GSM/GPRS operation, generating 10-20 Watts LTE power output with a power consumption of only 65-80 Watts. We also prepared new features and updates for YateHSS/HLR after receiving relevant feedback from our customers. And there is the new YateBTS website, which now offers extensive information on our products, solutions and our technology.

SatSite Model 142 launch

The LTE SatSite Model 142 delivers software-selectable LTE or GSM/GPRS operation from the same base station.

LTE_SatSite_142

In both LTE and GSM/GPRS modes, the SatSite Model 142 generates a higher output power than the previous model. As an eNodeB, the SatSite operates at up to 20 Watts, at bandwidths of 1.4 to 20 MHz, while in GSM/GPRS mode the SatSite operates at up to 20 Watts for 1-TRX or 2 Watts/TRX in multi-TRX configuration (at up to 4-TRX). The SatSite weighs only 5kg and has a low enough power consumption that it can be easily powered by solar panels in most of the world.

Its required backhaul is under 100 Mbit, resulting from the fact that, unlike many LTE solutions, the SatSite is a unified LTE eNodeB, and not a remote radio head (RRH) that needs a separate baseband unit (BBU).

For more information about Model 142’s complete specifications, please check the datasheet.

YateHSS/HLR new features

On the core network side, we start 2016 with new features to the YateHSS/HLR: scalability (cluster configuration), multi-IMSI support and support for separate circuit-switched/packet-switched network profiles.

Cluster configuration allows YateHSS/HLR nodes to work in a cloud to provide scalability. YateHSS/HLR servers all provide the same service and handle the same subscribers. If a server fails, the subscribers are distributed to the other YateHSS/HLR nodes in the cluster, which continues to provide the same services.

Multi-IMSI support allows YateHSS/HLR to respond to an alternative IMSI from the same SIM card, in different roaming scenarios. The feature sends an HTTP request to the operator’s server after the subscriber tries to roam into a new network. The operator’s server uses the request to trigger an IMSI change in the SIM using an OTA mechanism. The SIM carries a multi-IMSI application that ensures that the SIM will return to the main IMSI if it cannot register with the alternative IMSI.

The support for separate CS/PS profiles means that subscribers’ profiles are grouped according to the types of services associated to them, allowing the profiles to be easily updated to provide new services. For example, a subscriber might have “Prepaid voice, roaming”, “Prepaid data 1Mbps, not roaming” and “LTE not allowed” settings. It is easy to change one service of a subscriber by simply selecting another profile.

A few final words…

We have entered 2016 with great new core network features and new RAN product releases, making new opportunities for operators. Follow us on Twitter, LinkedIn, YouTube and Facebook to find out first about our new  announcements and releases.

 

YateUCN, the EPC cloud

The YateUCN is an LTE EPC that unifies all the functions of a conventional LTE core network into a single server. A single YateUCN unit combines the MME, SGW, PGW, PCEF and PCRF functions. A pool of YateUCN servers provide seamless horizontal redundancy, scalability and load balancing in the LTE core network. The YateUCN also replaces the latest core network approaches to design and management, such as network function virtualization (NFV) that virtualizes the functions of the network’s nodes in software or software-defined networking (SDN) that splits the control plane from the user plane.

A conventional LTE core network has many components and each requires a back-up node for redundancy. To ensure load balancing, operators need to deploy load balancers and external servers, which only add to the complexity count.

The YateUCN servers that form the EPC cloud have a many-to-many relationship with the eNodeBs, are equal at application lever, and eliminate the single point of failure between the RAN and the core network. All these characteristics allow for horizontal redundancy, load balancing, easy management and an overall simplicity within the network.

yucn_redund_epc_2015-11-18_version1.2_compare1.1

Redundant EPC

In conventional LTE networks, all core network components (MME, SGW, PGW, PCEF, PCRF) need to be duplicated to ensure redundancy and synchronization in case of failure. With a YateUCN-based core network, operators add extra servers to the existing pool to increase the network’s overall capacity.

To achieve redundancy, subscribers get assigned to random servers from the YateUCN pool. If a YateUCN fails, all the devices served by that unit are automatically re-assigned to other available YateUCN servers, as seen in the diagram.yucn_redund_epc_2015-11-18_version1.3

LTE core network cloud

A cluster of YateUCN servers act as an LTE core network cloud, providing all the EPC services: mobility, authentication, quality of service, routing upload and download IP packets, IP address allocation and more. Mobile operators eliminate the occurrence of a single point of failure between the RAN and the core network because YateUCN servers are equal at application level, and have a many-to-many relationship with the eNodeBs.

By removing the single point of failure possibility, mobile carriers can build scalable and considerably leaner core networks, while also providing load balancing for enhanced flexibility.

Each YateUCN core network server is implemented in off-the-shelf servers commodity software (Linux), offering a shorter lead time, more servicing options and faster replacement time.

Integration in existing LTE networks

The entire LTE EPC layer is implemented in a single YateUCN unit, meaning that it replaces the MME, the SGW, the PGW, the PCEF and the PCRF units of conventional networks.

The YateUCN is compatible with any generic LTE RAN and core network component. It supports the S1-AP and GTP interfaces between its MME and SGW functions and the eNodeBs. The YateUCN uses Diameter (S6a) to connect to an existing generic Home Subscriber Server (HSS). The unified server can connect to external PGW and SGW via the S5/S8 interface. To link to an existing IMS, to the Internet or to an MMS service, the YateUCN uses the SGi interface. Finally, to interrogate an external Equipment Identity Register (EIR) about blacklisted IMEIs, the YateUCN uses S13 over Diameter.

Additionally, the YateUCN also implements the IMS functions necessary for deploying VoLTE, but this will be detailed in a future article. In the meantime, previous blog posts have detailed the YateUCN’s VoLTE call with an iPhone 6 or how the YateUCN handles SRVCC.

A few final words

A unified core network server that delivers redundancy, scalability, load balancing and flexibility allows mobile operators to tap new core network equipment innovations and reduce their CAPEX. Easily integrated in an existing LTE network, the YateUCN makes it possible for mobile carriers to optimize their networks and replace solutions typically characteristic to the recent mobile LTE deployments, such as NFV or SDN.

YateUCN – the redundant MSC/VLR

Traditionally, the redundancy of the Mobile Switching Center / Visitor Location Register (MSC/VLR) is obtained through redundant dedicated hardware and software. The problem lies in the Abis + A interfaces (BSSAP protocol) which do not allow a base station to move easily to another MSC/VLR. To overcome this problem, we decided to use the SIP protocol (with enhanced features for GSM operations), which allows a YateBTS SatSite base station to move to another YateUCN (MSC/VLR) automatically and quickly.

Redundant GSM MSC/VLR

In a GSM network deployed with YateBTS-based SatSite base stations and YateUCN core network servers, each subscriber is randomly assigned to a YateUCN from a pool of core network servers. Operators can increase the redundancy of the pool by simply adding additional YateUCN servers for excess capacity in case a unit malfunctions. Therefore, handsets connected to a single SatSite can be served by multiple identical YateUCNs, while, at the same time, a single YateUCN serves multiple SatSite units. If a YateUCN server fails, all the mobile devices served by it are automatically moved to the other available YateUCN servers. When the subscriber is registered to the new YateUCN, its location is updated in the HLR.

In short, YateUCN and the GSM YateBTS SatSite base stations form a many-to-many relationship, and this was made possible though a number of characteristics.

  • The GSM YateBTS SatSite implements all the functions of a conventional Base Station Controller (BSC).
  • The A interface (between the BSC and the MSC/VLR) was replaced with SIP (between YateBTS and YateUCN), making it possible to quickly re-associate handsets with different YateUCN servers.
  • All YateUCN servers are identical units that support many core network functions. Operators will only have to duplicate one component, as opposed to multiple in conventional networks.
  • YateUCN is implemented in commodity hardware (off-the-shelf servers) and software (Linux), delivering a shorter lead time, more servicing options and faster replacement time.

The diagram below illustrates the technology perfectly.

yucn_msc-vlr_2015-11-4_version1.1

Integration in an LTE core network

The SatSite and the YateUCN components are easy to integrate into existing LTE networks because 2G services are delivered in SIP. These GSM services are integrated into a 4G network by employing the same GTP and IMS interfaces that are typically used in conventional EPC/IMS core networks.

YateUCN implements the same SIP switch to both provide GSM services and connect to an existing IMS network. Thus, with both the SIP-powered RAN and core network products, operators’ migration from GSM to LTE turns into a much simpler process.

Integration in a GSM core network

As an MSC/VLR, YateUCN performs all the functions of other MSC/VLRs: mobility, authentication, speech call and SMS routing. The server supports authentication of handsets using the SIM/USIM (EAP-SIM/EAP-AKA) and SIP AKAv1-MD5 algorithms.

YateUCN can connect to any standard HLR via the SS7 MAP protocol, and to other MSCs and GMSCs through the MAP-E protocol, allowing it to be in any conventional GSM network.

A few final words

YateUCN brings something new to GSM equipment: affordable redundancy, scalability, and uncomplicated management into a single core network server. It is easy to integrate to existing GSM and LTE networks and can be easily upgraded with new features within the same hardware and allows operators a seamless network extension.

YateUCN – the solution for MVNO networks

With mobile consumers’ expectations on the rise, new business models proliferate. Mobile Virtual Network Operator solutions must differentiate to stay competitive and maximize their offerings.

MVNOs wishing to offer subscribers high quality voice and/or data services can use YateUCN as a GMSC (voice), a GGSN (GPRS), or a PGW (LTE data).

YateUCN supports billing integration through CAMEL, RADIUS, and Diameter.

YateUCN, the unified core network for GSM/GPRS and LTE is a software implementation of the functions and protocols from the 2G and 4G LTE core layers on a commodity server. For GSM and GPRS, YateUCN performs the functions of the MSC, VLR, SGSN, GMSC, and GGSN. From 4G LTE, it acts as an MME, SGW, PGW, and PCRF.

YateUCN can be used to operate either all of these functions (for MNOs) or one specific function (for MVNOs). Each case scenario is presented below.

mvno_yucn_2014-10-29_version1.2

  • YateUCN for voice (GMSC)

The GMSC (Gateway Mobile Switching Center) functionality serves to locate the subscriber’s HLR (Home Location Register) in a mobile-terminated call, and then to route the call. Based on the information from the originating MSC, YateUCN uses the HLR to find the MSC of the called subscriber; with the number assigned by the HLR, the GMSC then forwards the call to the destination MSC. As a GMSC, YateUCN also provides CAMEL support.

  • YateUCN for data (GGSN and PGW in a single component)

In 2G networks, YateUCN as a GGSN (Gateway GPRS Support Node) is responsible for establishing and maintaining the user’s IP session and for storing billing information. It routes the IP packets to the SGSN in the MNO network over GTP-C. Establishing the data session in the YateUCN core network is independent of the radio network and is performed by the same component which can act either as a GGSN or as a PGW. If a session is initiated in GPRS, the GGSN (YateUCN) will connect to the SGSN over GTP-C v1.

In an LTE network, YateUCN can act as a PGW (PDN Gateway) to assign the IP address to the UE. YateUCN only communicates with the SGW in the operator’s network (over the S8 interface) and supports both Diameter and RADIUS to connect to the charging function in the network. If the session is started in LTE, YateUCN will act as a PGW and will connect to the SGW over GTP-C v2. It is also possible for a session to be started in LTE and continued in a 2G or 3G network.

  • YateUCN for billing integration

YateUCN connects to any billing system used by the MVNO, for both voice and data sessions management. It supports the Diameter Ro interface for prepaid services and the Rf interface for postpaid billing. For real-time credit control over SIP, YateUCN implements the Diameter Credit-Control Application (RFC 4006) to connect to the MVNO’s Charging Server.

  • YateUCN for SIP users

YateUCN also offers support for PC2Call registered users.

The unified core network, YateUCN, provides a profitable and flexible solution for the different requirements of emerging MVNOs. Detailed information about how YateUCN works in 2G and 4G networks is available here.

Modernizing GSM networks – an ever difficult feat

GSM has turned 24 this year and throughout this time showed that it is invaluable for telephone calls and M2M applications. Many industry observers estimate that 2G will continue to be in use even after 3G is discontinued. But GSM networks are confronted with the difficult task of adapting to the new operating environments.

The modernization of GSM is particularly arduous when considering that equipment vendors and solutions providers have concentrated on developing components for newer networks (3G, 4G, even 5G) and less on innovating GSM network components. The SatSite is designed to serve either GSM, LTE, or mixed GSM/LTE networks working directly with the unified core YateUCN, proving that there’s still plenty of room for innovative results for GSM deployments.

The technology behind our GSM network equipment allows new techniques like radio resource sharing with LTE, running GSM from a remote radio head, applying SON or beamforming technologies, which are typical for LTE, to be applied to 2G networks. The result is a simplified and flexible network architecture, better management and reduced costs.

Spectrum sharing
The SatSite base station is based on commodity, off-the shelf,-hardware and can be software-‘switched’ to provide either GSM, LTE, or both. When running YateBTS for GSM, it communicates directly with the unified core network, eliminating the base station controller (BSC). This architecture, where the BTS connects straight to the core network and communicates to other BTS in the network over peering protocols is very similar to the architecture of LTE.

This is also what makes it possible to support multiple technologies in the same equipment. If one BTS uses the same frequency bands to provide both GSM and LTE access, operators may choose freely on how to allocate spectrum between them. Depending on the service use at a given time, operators can assign prioritize voice over data services and vice versa. We’ve detailed spectrum sharing between GSM and LTE in the SatSite here.

Self-Organizing Network
SON techniques feature dynamic self-configuration, self-optimization, and self-healing functions, which can be achieved due to the eNodeB not being controlled by a distinct BSC component as in the typical case of GSM. Without a BSC, SatSite base stations are able to connect to each other over peering protocols, allowing an exchange of neighbor information between units. This presentation offers more details on SON technology for mixed 2G/4G networks.

Beamforming
Beamforming relies on grouping the signals of multiple antennas and into one beam sent to a desired direction. It aims to reduce interference and obtain a better quality of a service for a certain user. Unlike MIMO, where the network sends different parts of the data stream on different antennas, beamforming combines the signals from the different antennas and sends them to one device. What’s more, as opposed to MIMO, beamforming does not require any support from the handset, making it suitable for use in any mobile network technology, be it 2G, 3G, 4G or even 5G, in the future.

Benefits of optimizing GSM networks include a better management of the network resources, reduced infrastructure costs and maintenance efforts, and the flexibility to upgrade or reprogram network functions.

Increasing the security of VoLTE with YateUCN

The emergence of VoLTE-capable devices is raising new security concerns for mobile network operators, as existing IMS deployments expose vulnerabilities in VoLTE handsets to other devices in the network. YateUCN unified core network brings a solution to these concerns by isolating SIP and RTP call legs between handsets.

b2bua_vs_sip_proxy_2015-10-13_image1

LTE uses an IMS network to deliver VoLTE (voice services), and does so via Session Initiation Protocols (SIPs). This makes the IMS network act as a SIP proxy, performing routing, session control, and registering the UE to VoLTE. Voice is delivered through RTP from one UE to the other. Therefore, in case of a security attack, it is theoretically possible for a third party to send additional information through a forged SIP message via the IMS, to the target UE.

b2bua_vs_sip_proxy_2015-10-13_image2

Voice communication in 4G LTE can also be subject to malicious acts at various layers of the channel, including at the IP packets level, the UDP, RTP, or even the codec level.

What’s more, SIP is also implemented directly in the baseband processor of the latest generation smartphones to allow subscribers to use VoLTE, making it easy to for a potential smartphone takeover to occur.

b2bua_vs_sip_proxy_2015-10-13_image3

For SIP signaling, YateUCN acts as a Back-to-Back User Agent server, ensuring a secure transmission of data. B2BUA allows SIP communication from the originating party (or User Agent) to be terminated at the one side of the network, where the message is verified. Any harmful information included in the received SIP message is eliminated and the message is recomposed to include only the information needed for the SIP to reach the end party.

The risk of attacks decreases since malicious data is not automatically allowed to pass from one UE to the other, and the split SIP messages are negotiated independently on the originating and terminating sides.

Unlike current IMS deployments, YateUCN allows the same message decoding, verification, and re-encoding of RTP by acting as a proxy. This also simplifies the deployment of Voice over LTE, since handsets only need to connect to YateUCN server.