In a previous blog, we talked about the 5G requirements (Latency<1 msec. and bandwidth>1 Gbps) and services that can be considered true 5G use cases. We also mentioned that 5G enabled services will require a delay time of less than 1 msec. and that to meet this requirement content servers will have to be less than 1 km from the user’s device. This constraint of 1 km creates the need, in terms of interconnection, for greater co-operation between operators. According to GSMA, ultimately, it would make sense for a single network infrastructure to be implemented and shared between operators. This concept of a single network infrastructure seems to align quite well with the dream for an open market where new entrants could coexist harmoniously with giant operators via LTE virtualization, as LTE virtualization could enable Auctioned Based Dynamic Spectrum Sharing (ABDSS).
LTE Virtualization is becoming a reality. The LTE network is composed of 2 main components: the Evolved Radio Access Network (E-RAN) and the Evolved Packet Core (EPC). The E-RAN is composed of a collection of eNodeBs, while the EPC comprises different network elements: MMEs, Serving Gateway (S-GW), PDN Gateway (P-GW), PCRF, and HSS. Figure 1 (taken from ref. 1) shows the basic architecture of the LTE Network. EPC virtualisation solutions are available according to many equipment vendors, but the E-RAN is not. The E-RAN/eNodeB is the entity responsible for accessing the radio channels and scheduling the air interface resources, it had to be virtualized to enable ABDSS.
There is much ongoing research on E-RAN and eNodeB Virtualization. The framework architecture that seems to generate consensus is depicted in Figure 2. It adds a Hypervisor layer that does not exist in the current non-virtualized E-RAN/eNodeB architecture. In the non-virtualized E-RAN architecture, bandwidth is preconfigured and the eNodeB MAC scheduler takes care of subdividing it into Physical Resource Blocks (PRBs), which is the smallest unit that can be assigned to a user. In a virtualized environment, the Hypervisor layer will take care of managing the overall spectrum and schedule PRBs between different virtual operators.
Is it more that technology for infrastructure is nearly ready? The required cloud computing platforms like OpenStack, Eucalyptus, OpenNebula, and many others contain most of the required functions (Networking, Hypervisor Management, Control and Monitoring of physical/virtual Infrastructure, etc.) for the implementation. The only remaining question is: what’s the financial interest for the giant operators to adhere to this effort?
- 3GPP TS23.401 V13.2.0
- Networking 2011 Workshops: Realizing the Broker Based Dynamic Spectrum Allocation through LTE Virtualization and Uniform Auctioning Yasir Zaki1, Manzoor Ahmed Khan2, Liang Zhao1