IVC 5G O-RAN Summary

# IVC 5G O-RAN Summary ###### tags: `UNILA` # Summary 7 : Functional Split and Open Fronthaul Interface (OFI) Nama : Hans Khalif Hafif Student ID : 1915031078 Team : A-3 The description of the functional splits follows the LTE protocol stack known from the traditional BSs. The lower part of this protocol stack includes three layers; lowest is the physical layer, then follows the data link layer and on top is the network layer. The functions implemented in the different layers are illustrated in figure 2. These layers, together with the consequences of placing a functional split between specific elements, are introduced in the following sections. The physical layer handles the conversion from digital bits to outgoing radio waves in the Downlink (DL) direction and reverse for the Uplink (UL) direction. The fronthaul bitrates for the functional splits in the physical layer depends on how many users are present in the current cell, as each user occupy a certain amount of symbols in one subframe. The functional splits in the physical layer have the centralization benefits that features such as carrier aggregation, Multiple Input Multiple Output (MIMO) and Coordinated Multipoint (CoMP) are efficiently supported . CoMP has been seen as one of the important 5G technology candidates to improve system performance. CoMP can be divided into two classes: Medium Access Control (MAC) layer coordination and physical layer coordination. Joint reception (JR) and joint transmission (JT) are the physical layer coordinated technologies . The functional splits in the physical layer require coordination from higher layers and therefore the latency requirements are very strict . According to , the Hybrid ARQ (HARQ) process located in the MAC, requires a round trip time of 5 ms, this corresponds to a maximum 40 km fiber distance between the CU and DU. Migration Towards Open Fronthaul Interfaces • gNB disaggregation drives emerging needs for unit testing in isolation, and peer emulation (DU, RU) Migration Towards Open Fronthaul Interfaces Dist Unit O-DU Radio Unit O-RU Centr Unit O-CU RF Timing O-RAN • Transformation towards Open Protocols require conformance and interoperability and performance test • New Function Splits change 5G Radio Unit complexity and require new test capabilities • Critical relationship between RF, Timing, and Fronthaul Protocols • FR1/FR2 3GPP radio test requires O-RAN deterministic stimulus and analysis