of functional split will determine the fronthaul/backhaul capacity requirements and associated latency specifications and The terms "remote radio head" abbreviated as RRH and "remote radio unit" abbreviated as RRU have the same meaning and will be used interchangeably in this book. 5G Network Architecture 5 performance. This will impact the network architecture planning, since it determines the placement of nodes and permissible distance between them. The core network in the 5G systems allows a user to access network services, indepen- dent of the type of access technology. The network service provider utilizes a common framework for authentication and billing via a unified customer database to authorize the access to a service independent of the type of access. The 5G system provides termi- nation points or points of attachment to the core network for control-plane and user- plane entities. These points are selected based on location, mobility, and service require- ments. They may dynamically change during the lifetime of a service flow, based on the aforementioned requirements. To achieve a unified core network, common mechanisms of attachment are supported for both 3GPP and non-3GPP ANs. The 5G system will allow simultaneous multiple points of attachment to be selected per device on a per-se- rvice flow basis. Control-plane functions and UPFs are clearly separated with appropri- ate open interfaces. Device types are characterized by a variety of attributes including three broad categories of interfaces, namely human-human (H-H), human-machine (H-M), and machi- ne-machine (M-M). Examples of devices that belong to these categories include smart- phones (H-H), robots (H-M) or (M-M), drones (H-M) or (M-M), wearable devices (H-M), smart objects and sensors (M-M), etc. The attributes and capabilities associated with these devices are varying such as high power/low power, energy constraint/non-energy constraint, high cost/low cost, high performance/low performance, delay sensitive/delay tol- erant, high reliability, 