5G Radio Enhancements
Open5GCore implements the complete radio signaling protocol stack for the current LTE-Uu interface, aiming to bridge the physical wireless research area with the core network. Through further adaptations, the LTE/5G signaling constitutes the basis for the further research into the RAN area as well as in the definition of the appropriate borders between fronthaul and backhaul, RAN and core network.
The LTE/5G Signalling within Open5GCore includes the following new protocols and functional features:
- Non-Access Stratum (NAS) (UE side): includes the complete protocol with simplified EMM state machine (currently not supporting dedicated bearers, MAPCON, etc.);
- Radio Resource Control (RRC): complete protocol implementation with an extended state machine supporting attachments, detachments and handovers;
- Packet Data Convergence Protocol (PDCP): basic PDUs support. Integrity and cyphering functions as well as header compression may be easily added on demand;
- Radio Link Control (RLC) – supports transparent and unacknowledged modes and partially acknowledged mode;
Additional features were implemented to complete the LTE/5G signaling towards the PHY:
- MAC emulation – implements the protocol including the channel allocation
- Support of Small Cell Forum API towards PHY
- Minimal scheduler using MAC emulation and PHY over Ethernet
- Simulation of PHY over Ethernet
Additional protocols supported from the legacy EPC core (directly ported from OpenEPC Rel. 5):
- Non-Access Stratum (NAS) (MME side): includes the session and the mobility state machines for the UEs
- S1-AP Protocol – protocol implemented with a simplified state machine including the most representative features
- SCTP – basic protocol implemented. No needs for further extensions are foreseen at the moment
- GTP-U – protocol implemented since OpenEPC Rel. 3.
Through the subscriber oriented functionality of Open5GCore radio protocols, new radio resource scheduling and integration with radio PHY can be easily achieved and demonstrated into a comprehensive environment as well as novel research into the area of flexible radio access network architectures such as C-RAN, integration of small cells, local coordination of access network selection, fronthaul/backhaul protocol end-points selection etc.
On demand integration with LTE/5G PHY prototype implementations and products is possible and welcome.