User's Manual

Ver.
CHAPTER 2. System Overview
2600-00FKQFGA2
1.0
Direction Item Description
to fast movement of the UE.
- Closed-loop SM: The SM that works with the Precoding
Matrix Indicator (PMI) feedback of the UE when the UE’s
channel is known or changes slow due to slow
movement of the UE.
Uplink UL Transmit Antenna
Selection
The 1 RF chain/2Tx antenna is used; and the eNB
notifies the UE what Tx antenna to use. (Closed-loop
selection of Tx antenna)
Multi-User (MU) MIMO
or Collaborative MIMO
The peak data rate of each UE is not increased but the
cell throughput is increased. In the uplink, two different
UEs use the same time/frequency resources for
transmitting different data at the same time. The eNB
uses a single Tx antenna for selecting two orthogonal
UEs.
2.2.2 Call Processing Function
Cell Information Transmission
In a serving cell, the eNB periodically transmits a Master Information Block (MIB) and
System Information Blocks (SIBs), which are system information, to allow the UE that
receives them to perform proper call processing.
Call Control and Air Resource Assignment
The eNB allows the UE to be connected to or disconnected from the network.
When the UE is connected to or released from the network, the eNB transmits and receives
the signaling messages required for call processing to and from the UE via the Uu interface,
and to and from the EPC via the S1 interface.
When the UE connects to the network, the eNB performs call control and resource
allocation required for service. When the UE is disconnected from the network, the eNB
collects and releases the allocated resources.
Handover
The eNB supports intra-frequency or inter-frequency handover between intra-eNB cells,
X2 handover between eNBs, and S1 handover between eNBs. It also processes signaling
and bearer for handover. At intra-eNB handover, handover-related messages are transmitted
via internal eNB interfaces; at X2 handover, via the X2 interface; at S1 handover, via the
S1 interface.
To minimize user traffic loss during X2 and S1 handovers, the eNB performs the data
forwarding function. The source eNB provides two forwarding methods to the target eNB:
direct forwarding via the X2 interface and indirect forwarding via the S1 interface.
The eNB allows the UE to receive traffic without loss through the data forwarding method
at handover.
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