Kumu Networks Self Backhaul UE Relay User manual

Kumu Self Backhaul UE Relay User Guide v1.1
Kumu Networks, 960 Hamlin Ct, Sunnyvale, CA 94089, www.kumunetworks.com
Self Backhaul UE Relay
User Guide

Kumu Self Backhaul UE Relay User Guide v1.1
Kumu Networks, 960 Hamlin Ct, Sunnyvale, CA 94089, www.kumunetworks.com
Table of Contents
1 Overview ............................................................................................................................................... 4
2 Architecture & Theory of Operation..................................................................................................... 4
2.1 System Fit...................................................................................................................................... 4
2.2 Product Architecture..................................................................................................................... 5
2.3 eNB Interoperability...................................................................................................................... 7
2.3.1 Physical Connectivity to Small Cell........................................................................................ 7
2.4 Connectivity to Core Network....................................................................................................... 7
2.5 Connectivity to Management ....................................................................................................... 8
2.5.1 Keep alive.............................................................................................................................. 8
2.5.2 Physical Ethernet Connectivity ............................................................................................. 9
2.6 UE Characteristics ......................................................................................................................... 9
2.6.1 Transmitter requirements..................................................................................................... 9
2.6.2 SIM Card................................................................................................................................ 9
2.6.3 SIM Card PIN (CPIN) .............................................................................................................. 9
2.6.4 APN Configuration................................................................................................................. 9
2.6.5 RF Channel Configuration ..................................................................................................... 9
2.6.6 Physical Cell ID (PCI).............................................................................................................. 9
3 Electrical HW Architecture & Functionality ........................................................................................10
3.1 Access Front End ......................................................................................................................... 10
3.1.1 Unduplexer.......................................................................................................................... 10
3.1.2 Duplexer.............................................................................................................................. 10
3.1.3 Cancellation Module –Uplink............................................................................................. 10
3.2 Relay Backhaul ............................................................................................................................ 10
3.2.1 UE ........................................................................................................................................ 10
3.2.2 Motherboard....................................................................................................................... 10
3.2.3 Switch..................................................................................................................................10
3.2.4 Cancellation Module –Downlink ........................................................................................10
3.2.5 Backhaul Duplexer Module................................................................................................. 10
4 Software Architecture & Functionality ............................................................................................... 10

Kumu Self Backhaul UE Relay User Guide v1.1
Kumu Networks, 960 Hamlin Ct, Sunnyvale, CA 94089, www.kumunetworks.com
5 Testing.................................................................................................................................................11
6 Electrical / Mechanical / Environmental............................................................................................. 11
6.1 General Requirements ................................................................................................................ 11
6.2 Electrical Interfaces..................................................................................................................... 12
6.2.1 Ethernet Interfaces ............................................................................................................. 12
6.2.2 Power Interface................................................................................................................... 12
6.2.3 Access RF Interface (Antenna + eNB).................................................................................. 12
6.2.4 Backhaul RF Interface (Antenna + UE) ................................................................................ 12
6.2.5 SIM Card.............................................................................................................................. 13
6.2.6 LEDs.....................................................................................................................................13
7 Regulatory Information.......................................................................................................................14

Kumu Self Backhaul UE Relay User Guide v1.1
Kumu Networks, 960 Hamlin Ct, Sunnyvale, CA 94089, www.kumunetworks.com
1Overview
The document describes the product requirements for a Full Duplex UE Relay based on Kumu Networks’
cancellation module. The product is designed to be paired with an external eNB, and backhaul the eNB
data to the nearest macro base station using the same access frequencies used by the eNB (and the
macro network).
This document focuses on the system requirements rather than the cancellation requirements.
2Architecture & Theory of Operation
2.1 System Fit
The Relay is an LTE self-backhaul product that uses the existing cellular bands to provide the backhaul
connection. This approach allows the use of the existing base stations without requiring additional
backhaul equipment at the site. Below is a diagram of a self-backhaul node. In this configuration the
Relay doesn’t look any different to the macrocell than a smartphone.
Figure 1 Relay network usage

Kumu Self Backhaul UE Relay User Guide v1.1
Kumu Networks, 960 Hamlin Ct, Sunnyvale, CA 94089, www.kumunetworks.com
2.2 Product Architecture
Conceptually an LTE self-backhaul Relay is an eNodeB with its Ethernet connection connected to a well
provisioned cellphone that talks to a base station. In the case of the Kumu Relay product the EnodeB is
external vendor equipment.
Figure 2 Relay data path block diagram
Additionally, the Kumu self-cancellation modules (indicated by the blocks UL and DL in the above figure)
allow the Relay to operate in full duplex approaching close to 2x the spectral efficiency of competitor’s
products. The self-cancellation is used to cancel the leakage of a given ports transmit signal into the
other ports receiver.
The CPU acts as a USB to Ethernet bridge as well as providing configuration, control and monitoring of
the unit. The EPC termination is provided by the EPC attached to the base station where the Ethernet
link from the attached eNode is encapsulated and forwarded via the internal UE air interface.
The control plane architecture is shown below where the physical layer connection is Ethernet for the
cancellation module UL and DL and external debug port and USB to the UE module inside the Relay.

Kumu Self Backhaul UE Relay User Guide v1.1
Kumu Networks, 960 Hamlin Ct, Sunnyvale, CA 94089, www.kumunetworks.com
Figure 3 Relay control plane block diagram
To summarize, the UE Relay connects to the eNB via Ethernet port, for data transport, and via the
antenna port, to enable self-interface cancellation for full-duplex operation. The UE Relay provides
backhaul connectivity for the eNB in the form of LTE that transports the data through the operator
commercial wireless network. Otherwise, only power is required for operation.

Kumu Self Backhaul UE Relay User Guide v1.1
Kumu Networks, 960 Hamlin Ct, Sunnyvale, CA 94089, www.kumunetworks.com
2.3 eNB Interoperability
The Full-Duplex UE Relay is designed to operate with any off-the-shelf eNB that meets the following
criteria:
Technology
FDD LTE
Tx Power
2 x 5W (alpha) or 2 x 10W (beta)
Bandwidth
Single channel up to 20MHz
MIMO
2 x 2
Bands
B2 (PCS - North America)
B3 (1800MHz - International)
Each band represents a separate SKU. Multi-band solution would be introduced in the future.
2.3.1 Physical Connectivity to Small Cell
The UE Relay connects to the eNB both via the data port and the RF ports:
Data
RJ-45
Ant0
N-Type
Ant1
N-Type
2.4 Connectivity to Core Network
While the UE Relay provides backhaul to the Gi, it is the responsibility of the eNB to establish a secure
connection to a Security Gateway (Sec-GW) of the operator, from which it would be further connected
to the EPC.
The UE Relay attempts to be as transparent as possible for the small cell and the EPC. However, the UE
Relay is not completely transparent in the fact that it performs Network Address Translation (NAT). The
UE Relay performs NAT between the local subnet connecting it to the small cell and the IP address
provided by the LTE operator to the UE Relay. To traverse the NAT function, the eNB is expected to
support NAT-T or encapsulate IPsec traffic in UDP header.

Kumu Self Backhaul UE Relay User Guide v1.1
Kumu Networks, 960 Hamlin Ct, Sunnyvale, CA 94089, www.kumunetworks.com
2.5 Connectivity to Management
There are two options for connectivity of management/monitoring for the Kumu relay backhaul:
1) Provide out of band backhaul. The secondary Ethernet connection provides this functionality
when connected to a microwave or other similar link
2) Use the in-band backhaul over the UE connection. In the current relay implementation, the UE
supports a single APN.
As a result, the Kumu monitoring/management server must either:
1) Be able to reach the same protected subnet that the backhaul APN and ePC Security Gateway
external interface are a part of
2) Be deployed into the operator network.
2.5.1 Keep alive
To UE Relay periodically PINGs the network to test connectivity in an attempt to quickly discover failures
and take the necessary actions to restore normal operation. The following parameters are configurable
for this feature:
-Destination IP address (typically the address of the Security Gateway)

Kumu Self Backhaul UE Relay User Guide v1.1
Kumu Networks, 960 Hamlin Ct, Sunnyvale, CA 94089, www.kumunetworks.com
2.5.2 Physical Ethernet Connectivity
The UE Relay exposes two Ethernet ports –one for local configuration/bring-up and the other for
connectivity to the small cell. Each interface is pre-allocated an IP address that can be reprogrammed
through the management interface.
2.6 UE Characteristics
The UE transmits at a maximum of 24dBm per 3GPP specifications, power controlled by the macro base
station.
UE chip and stack vendor
Qualcomm MDM 9225
UE Category
Cat-4
Tx Power
1 x 24dBm at the UE module
Bandwidth
5, 10, 15, 20MHz
MIMO
1 x 2
Full-Duplex Bands
B2 (PCS - North America)
B3 (1800MHz - International)
Each band represents a single
SKU. Multi-bands SKUs may be
available in the future.
UE IP addresses are automatically assigned by the network. The UE is using IPv4 addresses for routing.
2.6.1 Transmitter requirements
Max power, Min power, ACLR,
2.6.2 SIM Card
The UE Relay uses 2FF (standard) SIM Card that can be inserted without opening the enclosure, through
a slot with weather-protected door. It is recommended that the operator uses high-priority SIM card for
this application.
2.6.3 SIM Card PIN (CPIN)
Through the management system, a CPIN can be configured to offer further network protection in case
the SIM card is jeopardized.
2.6.4 APN Configuration
The UE Relay supports a single APN and can be configured via the GUI
2.6.5 RF Channel Configuration
Each UE Relay is designed to operate in a full-duplex mode in a single band (2, 3, 4, or 7). Within each
band, an administrator needs to configure the specific channel of operation in the form of:
-EARFCN (Center Frequency)
2.6.6 Physical Cell ID (PCI)
The UE Relay allows an administrator to view the PCI the UE is connected to (if the UE is actually
connected to the network). The administrator may reconfigure a different PCI to which the UE should
connect. The administrator may also opt to “lock” the PCI to a specific desired physical cell.

Kumu Self Backhaul UE Relay User Guide v1.1
Kumu Networks, 960 Hamlin Ct, Sunnyvale, CA 94089, www.kumunetworks.com
3Electrical HW Architecture & Functionality
External interfaces covered in the “electrical/mechanical/environmental” section below.
3.1 Access Front End
3.1.1 Unduplexer
Band
Manufacturer
Part Number
2
MCV-Microwave
DDCC1880‐1960‐60A2
3
MCV-Microwave
DDCC1747‐1842‐75A2
3.1.2 Duplexer
Band
Manufacturer
Part Number
2
MCV-Microwave
DDCC1880‐1960‐60B1
3
MCV-Microwave
DDCC1747‐1842‐75C1
3.1.3 Cancellation Module –Uplink
Consult relevant Band 2-3 Uplink Cancelation Module spec
3.2 Relay Backhaul
3.2.1 UE
3.2.2 Motherboard
Kumu PN
Description
820-000009 rev A
PC, Intel NUC NUC5i5RYK, USB3, 8GB DDR3 CT2KIT51264BF160B
820-000010 rev A
Module, 8GB Kit (4GBx2) DDR3L 1600 MT/s (PC3L-12800) SODIMM 204-Pin
820-000026 rev 1
Preprogrammed SSD with current Relay Gen5B baseline image
3.2.3 Switch
Kumu PN
Description
820-000008 rev A
Advantech Corp 5PORT GBE LITE MANAGE EKI-5725I-AE
3.2.4 Cancellation Module –Downlink
Consult relevant Kumu Band 2-3 Downlink Cancelation Module spec
3.2.5 Backhaul Duplexer Module
Consult relevant Kumu Band 2-3 Backhaul Duplexer spec
4Software Architecture & Functionality