What is eNodeB?
The eNodeB, or evolved NodeB, is a critical component of the Long Term Evolution (LTE) network architecture. It functions as the base station for LTE cellular networks. In addition, it serves as a high-speed data switch that interfaces with User Equipment (UE) devices and the core network infrastructure.
The key functions of this component include radio resource management, radio frequency signal processing, packet processing, mobility management, authentication, and security.
Sophisticated algorithms and protocols, such as Orthogonal Frequency Division Multiple Access (OFDMA) and Multiple Input Multiple Output (MIMO) technology enable the eNodeB to dynamically allocate radio resources and ensure the efficient and secure transmission of data across the network.
Nybsys eNodeBs at the edge of the network follow the latest 3gpp specifications and are implemented using a versatile software framework, that has been at the forefront of many business-critical LTE deployments around the world. The system is built using COTS hardware but modified with our own BMC which protects from unwanted access by malicious actors. The system is open so that it can be inspected and modified if required. Our eNodeBs are designed and tested to operate in high humidity and high-temperature conditions. A high-level overview of our eNodeBs follows.
Physical Layers of our eNodeB
LTE protocol stack functions consist of Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and Radio Resource Control (RRC). LTE is the latest generation of the 3GPP standards. The LTE standard specifies an IP-only network supporting data rates up to 150 Mbps. These high data rates will enables new applications and services such as voice over IP, streaming multimedia, videoconferencing or even a high-speed cellular modem. The following are the supported specification in our proposed LTE eNodeB.
- LTE release 14 compliant
- FDD and TDD configurations
- Supported bandwidths: 1.4, 3, 5, 10, 15 and 20 MHz
- Handle several cells in intra-band or inter-band configurations
- Transmission modes: 1 (single antenna) and 2 to 10 (MIMO 4×4)
- Wideband CQI/PMI reports
- HARQ support
- Timing measurement thru the PRACH
- Closed-loop UE power control
- Frequency based MMSE equalizer
- Highly optimized software turbo decoder
- PAPR reduction support
- Support of other radio heads can be added with an external shared library.
- Positioning Reference Signals (PRS) support
- CSI-RS support
- Multi-cluster PUSCH allocation
- PUCCH 3 and PUCCH channel selection support
- Carrier Aggregation support with cross carrier scheduling (tested with 3 DL channels, supports up to 5 DL channels)
- CoMP testing features (DMRS scrambling identity and QCL parameters can be selected)
- 256QAM DL support for PDSCH and MBMS
- Support of release 11 TDD special subframe configurations 7 and 9
Protocol Layer of Evolved Node B (eNodeB)
LTE protocol stack functions consist of the Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and Radio Resource Control (RRC). LTE is the latest generation of the 3GPP standards. The LTE standard specifies an IP-only network supporting data rates up to 150 Mbps. These high data rates will enables new applications and services such as voice over IP, streaming multimedia, videoconferencing or even a high-speed cellular modem. The following are the supported specification in our proposed LTE eNodeB.
- LTE release 14 compliant
- Implements the MAC, RLC, PDCP and RRC layers
- Proportionally fair MAC scheduler with QoS support
- Support of full and half duplex UEs
- DRX support
- Number of active users only limited by the available bandwidth.
- Fully configurable System Information Blocks
- Integrity check and encryption using the AES, Snow3G and ZUC algorithms
- Support of RRC measurement with measurement gap
- Supports intra eNodeB, S1 or X2 handovers
- QoS support with user selectable DRB configuration for each QCI
- ROHC support (RTP, UDP and IP v1 profiles)
- Public Warning System (CMAS/ETWS) support
- MBMS support
- Category 0 UE support
- eDRX support
Long Term Evolution for Machines: LTE-M. It specifically refers to LTE CatM1, suitable for the IoT. LTE-M is a low power wide area technology which supports IoT through lower device complexity and provides extended coverage, while allowing the reuse of the LTE installed base. LTE M is popular for connecting sensors for military deployments for example helmet sensors can directly interact with the centralized command and control system using LTE M technologies. Following are the supported features for LTE M:
- Release 14 compliant
- Category M1 UE support
- TM6 and TM9 support
- FDD only (FDD and HD-FDD UEs are supported)
- Support of multiple CE levels (only CE-Mode A is supported)
- Support of message repetition for MPDCCH, PDSCH and PUSCH in full duplex. No message repetition for PUCCH and PRACH
- Support of localized MPDCCH transmission
- EPDCCH support for Category M1
- No frequency hopping
- Bandwidth must be >= 5 MHz
Narrowband IoT (NB-IoT) is a Low Power Wide Area Network (LPWAN) radio technology standard developed by 3GPP to enable a wide range of cellular devices and services. The specification was frozen in 3GPP Release 13 (LTE Advanced Pro), in June 2016. The following are the supported features of NB-IOT in our eNodeB infrastructure components.
- NB-IoT release 14 compliant
- Single-tone and multi-tone category NB1 and NB2 UE support
- 15 kHz and 3.75 kHz subcarrier spacing are supported
- All operation modes (in-band, guard band and standalone) are supported
- Multiple NB-IoT and LTE cells can be used at the same time in the same eNodeB
- Support of multiple coverage levels
- Support of all NPDCCH, NPDSCH, NPUSCH and NPRACH configurations
- Support of control plane CIoT optimization
- Support of multi-DRB mode
eNodeB Radio Interface
Proposed eNodeB is a software platform installed in COTS hardware which can be virtualized and can operate as virtual RAN. The following radio interfaces will be supported by the proposed eNodeB:
- C radio API to integrate any radio device
- Compatible with various SDR platform and high power RRH
eNodeB Network Interface
The software based eNodeB needs to support different network interfaces. Most of the interfaces are connected by using different VLAN or segment in the IP networks. The following interfaces are supported by proposed eNodeB:
- Standard S1AP and GTP-U interfaces to the Core Network. Several PLMNs and S1 interfaces can be used simultaneously.
- X2AP interface between eNodeBs
- M1 and M2 interfaces for MBMS
- IPv6 support
eNodeB User Interface
- Configurable logging system for all channels with built-in text decoders
- Wireshark MAC-LTE capture
- Plots for QAM constellations and channel response
- Remote API using WebSocket
- Command line monitor
- Test commands to initiate handover and to dynamically change the power level of each cell