1. 單元1 Heterogeneous Networks 異質性行動寬頻網路簡介
教育部行動寬頻尖端技術人才培育計畫-小細胞基站聯盟中心
「小基站與WiFi之異質性網路存取」課程模組
單元1 Heterogeneous Networks 異質性行動寬頻網路簡介
助理教授：吳俊興
國立高雄大學 資訊工程學系

2. Outline Syllabus Next-Generation Mobile Networks
Review the Development of Mobile Networks
Toward 5G: IMT-2020 and LTE-Advanced Pro
HetNet’s Fundamental Technologies
LTE-CA: Carrier Aggregation
ICIC: Inter-Cell Interference Coordination
CoMP: Coordinated Multi Point
HetNet’s Advanced Technologies
RCLWI: RAN Controlled LTE WLAN Interworking
LWIP: LTE WLAN Radio Level Integration with IPsec Tunnel
LWA: LTE-WLAN Aggregation
LTE-U/LTE-LAA/LTE-LSA: Unlicensed, Licensed Assisted Access, Licensed Shared Access

3. 教學目標
本課程介紹行動寬頻的最新發展技術，探討小細胞基站 (Small Cells)如何整合各種無線網路，並支援異質性網路(Heterogeneous Networks)，以做為B4G/5G行動通訊網路的基礎。講授重點包括：
異質行動網路簡介，包括Licensed同步存取、Licensed與Unlicensed/WiFi 整合存取
HetNet以小基站為基礎之異質行動網路，包括ICIC干擾管理與CoMP多點協 調等小基站技術，以及RCLWI/LWIP/LWA/LAA等LTE與WiFi整合技術
另外，透過學習建置OAI-LTE平台或ITRI Small Cells-LTE平台並與WiFi無線網 路進行整合的系列實驗，來達成以下的目標：
培養學生利用WiFi進行卸載或負載分享的程式實作能力
學習在OAI平台或ITRI Small Cell平台上實作影音串流的卸載與負載分享等 相關的實驗技術
透過期末的LTE與WiFi整合的影音串流的卸載與負載分享的專題實作，培養 學生創意思考與解決問題之能力

4. 課程內容 單元 單元1：異質行動寬頻網路簡介 單元2：HetNet以小基站為基礎之異質性行動網路 單元3：ICIC干擾協調與CoMP多點協調
單元4：OAI-LTE與WiFi網路實驗平台的建置
單元5：多媒體影音串流在異質性網路上的QoS
單元6：LTE使用WiFi網路的卸載(Off-loading)
單元7：LTE與WiFi的負載分享排程演算法(Load Scheduling)
實驗1：OAI-LTE與WiFi網路整合的實驗平台的建置
實驗2：OAI-LTE與WiFi網路整合的實驗平台上的干擾量測
實驗3：OAI-LTE與WiFi網路整合的實驗平台上的QoS效能量測
實驗4：多媒體影音串流使用OAI-LTE與WiFi網路整合的卸載與負載分享

5. 課程教材 參考書 (eBook) Protocols (Specifications) Platforms
Joydeep Acharya, Long Gao, and Sudhanshu Gaur, Heterogeneous Networks in LTE-Advanced, John Wiley & Sons, Ltd, 2014
Chris Johnson, Long Term Evolution in Bullets, 2nd Edition, CreateSpace Publishing, 2012
Harri Holma, Antti Toskala, Jussi Reunanen, LTE Small Cell Optimization - 3GPP Evolution to Release 13, John Wiley & Sons, Ltd, 2015
Protocols (Specifications)
3GPP LTE-Advanced Pro
ITU IMT-2020
Small Cell Forum, LTE-U Forum, NGMN, 5G Americas, 5G PPP
Platforms
Open Air Interface
ITRI

6. Outline Syllabus Next-Generation Mobile Networks
Review the Development of Mobile Networks
Toward 5G: IMT-2020 and LTE-Advanced Pro
HetNet’s Fundamental Technologies
LTE-CA: Carrier Aggregation
ICIC: Inter-Cell Interference Coordination
CoMP: Coordinated Multi Point
HetNet’s Advanced Technologies
RCLWI: RAN Controlled LTE WLAN Interworking
LWIP: LTE WLAN Radio Level Integration with IPsec Tunnel
LWA: LTE-WLAN Aggregation
LTE-U/LTE-LAA/LTE-LSA: Unlicensed, Licensed Assisted Access, Licensed Shared Access

7. Mobile Networks from GSM to LTE
Core of 3GPP’s SAE Project (System Architecture Evolution)

8. Mobile Networks from GSM to LTE (Cont.)
GSM: developed to carry real time services, in a circuit switched manner
GPRS: the first step towards an IP based packet switched solution
Using the same air interface and access method, TDMA (Time Division Multiple Access)
UMTS: 3G standard based on GSM
Developing UTRAN and WCDMA
EPS (Evolved Packet System): purely IP based
A flat, all-IP architecture with separation of control plane and user plane traffic
Composed with E-UTRAN/LTE and packet-switched EPC (Evolved Packet Core)

9. Network Structure of UMTS (Universal Mobile Telecommunications System)
Mobile Station Access Network Core Network
Emulating a circuit switched connection for real time services and a packet switched connection for datacom services
Incoming datacom services are still relying upon the circuit switched core for paging
An IP address is allocated to the UE when a datacom service is established and released when the service is released

10. EPS (Evolved Packet System) / SAE
PDN (Packet Data Network)
Gateway
Serving Gateway
Access Network Discovery and Selection Function
Mobility Management Entity
Evolved Packet Data Gateway
Radio Access Network (RAN)
Core Network (CN)
A bearer is from UE to eNodeB to S-GW and finally to P-GW

11. EPC (Evolved Packet Core)
EPC (Evolved Packet Core): main component of EPS, includes
MME: key control-node for LTE – UE paging; chooses S-GW for UE during attach and handover
Authenticating the user (by interacting with HSS - Home Subscriber Server)
S-GW: manages and stores UE contexts; routes and forwards user data packets
P-GW: provides connectivity from the UE to external packet data networks
ePDG: secures data transmission with UE connected to EPC over untrusted non-3GPP access
ANDSF: provides information to UE to discover available access networks (either 3GPP or not)

12. Evolved Universal Terrestrial Radio Access (E-UTRA)
e-UTRA is the air interface of 3GPP's Long Term Evolution (LTE)
EUTRAN is a radio access network (RAN) which is referred to under the name EUTRAN standard

13. Protocol Models of CN and RAN
Two main layers
Upper layer: manipulate information specific to LTE
Lower layer: transport information from one point to another
Three types of protocols
(Control plane) signaling protocols
User plane protocols
Transport protocols: transfer data and signaling messages
On the air interface By the fixed network

14. Protocol Stack to Exchange Control Signaling
Stream Control Transmission Protocol  TS

15. Bearer Implementation (Using GTP)TS
GTP (GPRS Tunneling Protocol)

16. Challenges to Operators
Increasing data traffic: network capability using traditional macrocell-based deployments is growing at about 30% less than the demand for data
Decreasing profit margins: the profit margins of most operators have also been decreasing globally
The flat rate pricing policies prevent the mobile data revenues of an operator to scale proportionately with the increased usage of mobile broadband data
The cost incurred as a result of setting up more base stations to provide increased capacity and coverage
Rethink methods of operating their networks
Key principle: deliver higher capacity at a reduced cost

17. Enhancement of Key Capabilities from IMT-Advanced to IMT-2020
Source: ITU-R M (Sep 2015)

18. Ways to Increase Capacity
A 1000× increase in capacity is required to support rising demand in 2020*
High capacity can be achieved by
Improving spectral efficiency
Employing more spectrum
Increasing network density
The major gains are expected through increasing network density by deploying an overlay network of small cells over the macro coverage area
Related to link level enhancements (but already at near optimal)
*Reference: Mallinson, K. (2012) The 2020 vision for LTE. Available at (accessed November 2013)

19. Detailed Timeline & Process for IMT-2020 in ITU-R
Working Party 5D, Study Group 5, ITU-R (Radiocommunication)
FG IMT-2020, Focus Group on IMT-2020, SG 13, ITU-T (Telecommunication)

20. IMT-2020 Vision – A Unified Network Architecture
A Heterogeneous (Licensed) Network with Large and Small Cells (HetNet)
Carrier Aggregation (R8+) → eCA
Intra-band/inter-band contiguous/non-contiguous allocation
Interference Management
Inter-Cell Interference Coordination (ICIC, R8) → eICIC (R10) → feICIC (R11)
Dynamic Coordination between Neighboring Cells
Coordinated Multi Point (CoMP)
Simultaneous Connectivity across Cells
DualNet (TR R12)
A Heterogeneous Network Integrating (Unlicensed) WLAN/WiFi
WLAN inter-working (Trusted/Un-trusted)
WiFi Offload and Link Aggregation (LWIP, LWA)
LTE in the unlicensed spectrum
LTE-U, LAA (R13) / eLAA (DualNet R14)

21. 5G Vision – 5G-PPP EU Source: https://5g-ppp.eu/ (5G Vision, Feb 2015)

22. 3GPP Roadmap Phase 1: by Sep 2018/Rel-15 Phase 2: by Mar 2020/Rel-16
Address a more urgent subset of commercial needs (Not possible to standardize all in time)
Expected deployments in 2020
Phase 2: by Mar 2020/Rel-16
Target for IMT 2020 submission
Address all identified use-cases & requirements

23. 3GPP 5G Requirements
 TR with 70s different user cases of four groups (SA1 finalized June 2016)

24. 3GPP 5G Requirements (Cont.)
TR : Massive Internet of Things
focuses on use cases with massive number of devices (e.g., sensors and wearables), particularly relevant to the new vertical services, such as smart home and city, smart utilities, e-Health, and smart wearables.
TR : Critical Communications
Main improvements for Critical Communications are latency, reliability, and availability to enable, for example, industrial control applications and tactile Internet, to be met with an improved radio interface, optimized architecture, and dedicated core and radio resources.
TR : Enhanced Mobile Broadband
Enhanced Mobile Broadband includes higher data rates, higher density, deployment and coverage, higher user mobility, devices with highly variable user data rates, fixed mobile convergence, and small-cell deployments.
TR : Network Operation
Addresses the functional system requirements, including aspects such as: flexible functions and capabilities, new value creation, migration and interworking, optimizations and enhancements, and security.

25. Three Main 5G Cases and Examples
eMBB (enhanced Mobile Broadband)
mMTC (massive Machine Type Communications)
URLLC (Ultra-Reliable and Low Latency Communications) 

26. Outline Syllabus Next-Generation Mobile Networks
Review the Development of Mobile Networks
Toward 5G: IMT-2020 and LTE-Advanced Pro
HetNet’s Fundamental Technologies
LTE-CA: Carrier Aggregation
ICIC: Inter-Cell Interference Coordination
CoMP: Coordinated Multi Point
HetNet’s Advanced Technologies
RCLWI: RAN Controlled LTE WLAN Interworking
LWIP: LTE WLAN Radio Level Integration with IPsec Tunnel
LWA: LTE-WLAN Aggregation
LTE-U/LTE-LAA/LTE-LSA: Unlicensed, Licensed Assisted Access, Licensed Shared Access

27. Toward a Heterogeneous Network
Finding new macro-sites becomes increasingly difficult and can be expensive
Introduce small cells through the addition of low-power base stations (eNBs, HeNBs or Relay Nodes (RNs)) or Remote Radio Heads (RRH) to existing macro-eNBs
Added to increase capacity in hot spots with high user demand and to fill in areas not covered by the macro network – both outdoors and indoors
They also improve network performance and service quality by offloading from the large macro-cells
The result is a heterogeneous network with large macro-cells in combination with small cells providing increased bitrates per unit area
HetNet: a wireless network comprised of different types of base stations and wireless technologies, including macro base stations, small cells, distributed antenna systems (DAS), and even Wi-Fi access points

28. Deployment Scenarios of Small Cell (TR32.835)
A Heterogeneous Network consists of different types of Base Stations (BSs), supporting cells such as macro, micro and pico cells
These types of BSs will be mixed in an operating network
Heterogeneous networks management should consider cells in a heterogeneous network, including small cells
both with and without macro coverage,
both outdoor and indoor small cell deployments and
both sparse and dense small cell deployments
F1 and F2 are the carrier frequency for macro layer and local-node layer, respectively

29. HetNet - A Heterogeneous Network with Large and Small Cells
Low-power base station or RRH (Remote Radio Head)
Off load for large cell
Small site size
Indoor coverage
Hot-spot coverage
Coverage at cell edge of large cell
Coverage in area not covered by the macro-network
Large cell
High-power eNB
Macro-eNB site can be difficult to find
In heterogeneous networks the cells of different sizes are referred to as macro-, micro-, pico- and femto-cells; listed in order of decreasing base station power

30. From Macro to Small Cells
Small cells using 3GPP radio access technologies will
Enhance capacity and per-user throughput
Reduce costs and
Uniquely offer tight cooperation with the macro coverage layer
Enhancements for small cells as a key component of R12
Dual connectivity: Devices maintain simultaneous connections to both macro and small-cell low-power layers to improve cell-edge throughput
Inter-node radio resource aggregation can use radio resources on a common frequency in more than one eNB
Connections can be anchored to a macro cell on one frequency while boosting data-rates via the small cell on a different frequency
Small cell on/off: Energy-efficient load balancing by turning off the low-power nodes when there is no ongoing demand for data transmission
More eNBs increases air interface interference and network power consumption
Making nodes dormant can match available capacity to network traffic loading
256 QAM: Close proximity of devices to small cells enables use of higher-order modulation
Beneficial in sparse small-cell implementations with low device mobility

31. HetNet Dual Connectivity
Simultaneous connection to the macro and low-power layer

32. Carrier Aggregation
Carrier aggregation is used in LTE-Advanced in order to increase the bandwidth, and thereby increase the bitrate, by aggregating multiple carriers together for simultaneous transmission
The aggregation is based on R8/R9 carriers to keep backward compatibility with R8 and R9 UEs
Carrier aggregation can be used for both FDD and TDD
Reference: LTE Carrier Aggregation,

33. Component Carrier
Each aggregated carrier is referred to as a component carrier, CC
The component carrier can have a bandwidth of 1.4, 3, 5, 10, 15 or 20 MHz and
A maximum of five component carriers can be aggregated
Hence the maximum aggregated bandwidth is 100 MHz
In FDD the number of aggregated carriers can be different in DL and UL
However, the number of UL component carriers is always equal to or lower than the number of DL component carriers
The individual component carriers can also be of different bandwidths
For TDD the number of CCs as well as the bandwidths of each CC will normally be the same for DL and UL

34. Example of Carrier Aggregation (FDD)
The LTE-Advanced UE can be allocated DL and UL resources on the aggregated resource consisting of two or more Component Carriers (CC)
The R8/R9 UEs can be allocated resources on any ONE of the CCs
The CCs can be of different bandwidths

35. Band Allocation for Aggregation
Intra-band contiguous allocation
The easiest way to arrange aggregation would be to use contiguous component carriers within the same operating frequency band (as defined for LTE)
This might not always be possible, due to operator frequency allocation scenarios.
Intra-band non-contiguous allocation
The component carriers belong to the same operating frequency band, but have a gap, or gaps, in between
Inter-band non-contiguous allocation
The component carriers belong to different operating frequency bands

36. Intra-band and Inter-band Aggregation Alternatives
The spacing between the centre frequencies of two contiguous CCs is Nx300 kHz, N=integer
For non-contiguous cases the CCs are separated by one, or more, frequency gap(s)

37. Definitions and Notations for CA
CA is initially specified for only a few combinations of E-UTRA operating bands and number of CCs
New definitions to specify different CA combinations
Aggregated Transmission Bandwidth Configuration (ATBC): total number of aggregated physical resource blocks (PRB)
CA Bandwidth Class: indicates a combination of maximum ATBC and maximum number of CCs. In R10 and R11 three classes are defined
Class A: ATBC ≤ 100, maximum number of CC = 1
Class B: ATBC ≤ 100, maximum number of CC = 2
Class C: 100 < ATBC ≤ 200, maximum number of CC = 2
CA Configuration: indicates a combination of E-UTRA operating band(s) and CA bandwidth class(es), to exemplify the configuration
CA_1C indicates intra-band contiguous CA on E-UTRA operating band 1 and CA bandwidth class C
CA_1A_1A, indicates intra-band non-contiguous CA on band 1 with a one CC on each side of the intra-band gap
CA_1A_5B indicates inter-band CA, on operating band 1 with bandwidth class A and operating band 5 with bandwidth class B
Reference: E-UTRA CA configurations 36.101 (Rel 15 Sept 2017)

38. Three CA Configurations Defined for R10
Type of CA and  Duplex Type
CA Configuration
Maximum Aggregated Bandwidth (MHz)
Max Number of CC
Intra-band contiguous FDD
CA_1C 40 2
Intra-band contiguous TDD
CA_40C
Inter-band  FDD
CA_1A_5A 20
1 + 1

39. CA Configurations Defined for R11 and Beyond
In R11 a large number of additional CA configurations are defined
The maximum aggregated bandwidth is still 40 MHz and maximum number of CC is 2
For both R10 and R11 any UL CC will have the same bandwidth as the corresponding DL CC
Also for inter-band CA there will only be ONE UL CC, i.e. no UL CA
Check updated table in the “Carrier Aggregation for LTE” document for each release
Type of CA and  Duplex Type
CA Configuration
Maximum Aggregated Bandwidth (MHz)
Max Number of CC
Intra-band contiguous
FDD
CA_1C 40 2
CA_7C
TDD
CA_38C
CA_40C
CA_41C
Inter-band FDD
CA_1A_5A 20
1 + 1
CA_11A_18A 25
CA_3A_5A 30
CA_1A_18A 35
CA_3A_7A
Intra-band non-contiguous FDD
CA_25A_25A

40. The Primary Component Carrier (PCC) and Secondary Component Carriers (SCCs)
When carrier aggregation is used there are a number of serving cells, one for each component carrier
Different component carriers can be planned to provide different coverage, i.e. different cell size
The RRC connection is only handled by one cell, the Primary serving cell, served by the Primary Component Carrier (DL and UL PCC)
It is also on the DL PCC that the UE receives NAS information, such as security parameters.
In idle mode the UE listens to system information on the DL PCC
On the UL PCC PUCCH is sent
The other component carriers are all referred to as Secondary Component Carriers (DL and UL SCC), serving the Secondary serving cells
The SCCs are added and removed as required, while the PCC is only changed at handover
The coverage of the serving cells may differ, for example due to that CCs on different frequency bands will experience different path loss
In the case of inter-band carrier aggregation the component carriers will experience different path loss, which increases with increasing frequency
Note that for UEs using the same set of CCs, can have different PCC

41. Primary and Secondary Serving Cells
Each component carrier corresponds to a serving cell
The different serving cells may have different coverage
Carrier aggregation on three component carriers are used for the black UE
The white UE is not within the coverage area of the red component carrier

42. Changes to R8/R9 for Carrier Aggregation
Introduction of carrier aggregation influences mainly MAC and the physical layer protocol, but also some new RRC messages are introduced
In order to keep R8/R9 compatibility the protocol changes will be kept to a minimum
Basically each component carrier is treated as an R8 carrier
Some changes are required, such as
new RRC messages in order to handle SCC
MAC must be able to handle scheduling on a number of CCs
Major changes on the physical layer are for example that
Signaling information about scheduling on CCs must be provided DL as well as HARQ ACK/NACK per CC must be delivered UL and DL

43. Radio Interface to Support Carrier Aggregation

44. CA Scheduling (FDD): Two Main Alternatives
Either resources are scheduled on the same carrier as the grant is received, or so called cross-carrier scheduling may be used

45. Support Serving Cells with Different Timing Advance (TA)
Serving cells with the same TA belongs to the same TA Group (TAG)
From R11 it will be possible to handle CA with CCs requiring different timing advance (TA), for example combining CC from eNB with CC from RRH
For heterogeneous network planning the use of for example remote radio heads (RRH) is of importance

46. Inter-Cell Interference Coordination (ICIC)
Originally introduced in R8 for macro-cells
eNBs communicate using ICIC via the X2 interface to mitigate inter-cell interference for UEs at the cell edge
“Load Information” X2AP message
Used by an eNB to inform neighbouring eNBs about
UL interference level per Physical Resource Block (PRB);
UL PRBs that are allocated to cell edge UEs, and hence are sensitive to UL interference;
if DL Tx power is higher or lower than a set threshold value
The receiving eNBs use the received information to optimize scheduling for UEs at cell edges

47. eICIC to Support Heterogeneous Networks
Enhanced ICIC (eICIC) was introduced in LTE R10
Better support heterogeneous network deployments
Especially interference control for DL control channels
The major change is the addition of time domain ICIC, realized through use of Almost Blank Subframes (ABS)
Includes only control channels and cell-specific reference signals, no user data
Transmitted with reduced power
eICIC between macro-eNB and eNB in small cells
The macro-eNB will transmit ABS according to a semi-static pattern
During these subframes, UEs at the edge, typically in the Cell Range Expansion (CRE) region of small cells, can receive DL information, both control and user data
The macro-eNB will inform the eNB in the small cell about the ABS pattern

48. ABS for Cell-edge UEs in Small Cells (eICIC)
Further Enhanced ICIC (feICIC) in R11
Interference handling by UE through inter-cell interference cancellation for control signals
Enabling even further cell range extension
eICIC and feICIC are especially important when Carrier Aggregation (CA) is not used

49. CoMP – Coordinated Multi Point
CoMP introduced in LTE R11
One way to ensure that a UE is using both the best DL and the best UL carrier in a heterogeneous network (used both in DL and UL)
With CoMP
A number of transmission/reception points (i.e. eNBs, RNs or RRHs) can be coordinated to provide service to a UE. For examples,
Data can be transmitted at the same time in the same Physical Resource Blocks (PRB) from more than one transmission point to one UE, or
Data can be received from one transmission point in one subframe and from another transmission point in the next subframe

50. CoMP in a Heterogeneous Network
CoAP is especially useful in heterogeneous networks
The possibility for a UE in the cell range extension region to utilize the best UL in the small cell and the best DL in the macro-cell
A number of macro-cells and small cells can be involved in data transmission to and from one UE
Requires that
The macro-eNB and the base station in the small cell are synchronized
Most likely it will require a combination of macro-eNB with Remote Radio Heads (RRH) in the small cell

51. Example of CoMP
Using CoMP it is possible for the UE in the grey area to have both the best DL from the macro-eNB and the best UL to the base station, or RRH, serving the small cell

52. Outline Syllabus Next-Generation Mobile Networks
Review the Development of Mobile Networks
Toward 5G: IMT-2020 and LTE-Advanced Pro
HetNet’s Fundamental Technologies
LTE-CA: Carrier Aggregation
ICIC: Inter-Cell Interference Coordination
CoMP: Coordinated Multi Point
HetNet’s Advanced Technologies
RCLWI: RAN Controlled LTE WLAN Interworking
LWIP: LTE WLAN Radio Level Integration with IPsec Tunnel
LWA: LTE-WLAN Aggregation
LTE-U/LTE-LAA/LTE-LSA: Unlicensed, Licensed Assisted Access, Licensed Shared Access

53. LTE in the Unlicensed Spectrum
Two areas to help operators offload traffic in the unlicensed spectrum:
WLAN via LTE/WLAN Interworking (via offload or aggregation)
LTE over unlicensed spectrum
WLAN
Offload
Faster
LTE
Licensed
More Capacity
Link Aggregation
WLAN
Unified Network
Carrier Aggregation
Fair Coexistence
LTE
Unlicensed
Source: Keysight, March 2016

54. 3GPP Standardization Works
Rel. 12
Rel. 13
Rel. 14
Rel. 11
Rel. 10
LTE/WLAN
Interworking
LTE over unlicensed
eLAA
WLAN
Offload
RAN Assisted Interworking
RAN Controlled Interworking (RCLWI)
LAA
LTE-U
Aggregation
LWA
LWIP
Mar 2016
Jun 2017
eLWIP
eLWA
Uplink / Mobility
(LBT)
Interworking
RAN Controlled LTE-WLAN Interworking (RCLWI)
Link Aggregation
LTE-WLAN Aggregation (LWA)
LTE WLAN Radio Level Integration with IPsec Tunnel (LWIP)
Licensed Assisted Access (LAA)
Unlicensed band using carrier aggregation with a licensed LTE cell (3GPP Rel. 12)
Adaption: Keysight, March 2016

55. LTE/WLAN Integration
Roaming
/ RCLWI
LWIP
LWA
LAA
(LSA)
LTE +
WLAN

56. ANDSF
Access Network Discovery and Selection Function (ANDSF) is a network element specified in 3GPP TS 23.402 [6] to help UE know
Which network (3GPP or Non-3GPP) are available
Which network UE has to get access when UE detects 3GPP network and WiFi network
The UE-ANDSF interaction can take place via non-seamless WLAN offload or via any 3GPP or non-3GPP access technology that can be used by the UE to access EPC
ANDSF rules refers to the set of ANDSF policies defined in 3GPP TS  for WLAN access selection and traffic routing between E-UTRAN or UTRAN and WLAN
The term ANDSF is used to refer to both Home and Visited ANDSF
ANDSF rules can contain RAN validity conditions for RAN-assisted WLAN interworking
24.302

57. Non-3GPP Access
Non-3GPP access includes access from, for instance, Wi-Fi, WiMAX, fixed and CDMA networks
The Mobility mechanisms supported between 3GPP and non-3GPP accesses within an operator and its roaming partner's network would depend upon operator choice
The EPS supports the use of non-3GPP IP access networks to access the EPC
The 3GPP standard defines two types of non-3GPP access: Trusted and untrusted
The biggest difference between trusted access and untrusted access would be the requirement of authentication requirement
3GPP does not specify which non-3GPP technologies should be considered trusted or untrusted This decision is made by the operator
24.302

58. Trusted Non-3GPP Access
UE would not need any separate authentication/security process when it switches from 3GPP access to non-3GPP access (WiFi)
Since UE already has gone through this process when it was camping on the 3GPP access and network trust the process
Assume that the non-3GPP access can be protected by the same security procedure
In this access, it is highly likely that Network Operator distribute their own WiFi Access points and let UE get access through those Access Point
24.302

59. Untrusted Non-3GPP Access
Untrusted non-3GPP accesses interwork with the EPC via a network entity called the ePDG (for Evolved Packet Data Gateway)
The main role of the ePDG is to provide security mechanisms such as IPsec tunneling of connections with the UE over an untrusted non-3GPP access
24.302

60. Non-3GPP Access Network Detection
Access during initial attach or handover attach
A UE needs to discover the trust relationship (whether it is a Trusted or Untrusted Non-3GPP Access Network) of the non-3GPP access network in order to know which non-3GPP IP access procedure to initiate
The trust relationship of a non-3GPP access network is made known to the UE with one of the following options:
If the non-3GPP access supports 3GPP-based access authentication, the UE discovers the trust relationship during the 3GPP-based access authentication
The UE operates on the basis of pre-configured policy in the UE
24.302

61. Architecture for Access Network Discovery Support Functions
Non-Roaming
Roaming
23.402
The following architecture may be used for access network discovery and selection. The support and the use of these functions and interfaces are optional

62. Example: Inter-System (Roaming)
TS (v14.3, ) : Access to EPC via Non-3GPP Access Network
Signalling flow for inter-system change between 3GPP access network and non-3GPP access network

63. Handover from 3GPP Access to Trusted Non-3GPP Access
23.402
3GPP Access to Trusted Non-3GPP IP Access Handover with PMIPv6 on S2a

64. RCLWI - RAN Controlled LTE WLAN Interworking
Bi-directional traffic steering between E-UTRAN and WLAN for UEs in RRC_CONNECTED
Similar overall architecture and scenarios as for LWA
E-UTRAN may send a steering command to the UE indicating to steer traffic from E-UTRAN to WLAN or from WLAN to E-UTRAN
The upper layers in the UE shall be notified (TS24.302) upon reception of such a command
Access network selection and traffic steering rules defined in TS36.304

65. LWIP - LTE/WLAN Radio Level Integration with IPsec Tunnel (LWIP)
UE uses WLAN via IPsec tunnel between eNB and UE
Fast time to market, use of legacy WLAN infrastructure
WLAN is hidden from CN
Except for WLAN authentication
LWIP is controlled by eNB, based on UE measurement reporting
For security reasons IPsec tunnel is terminated in LWIP-SeGW in eNB
IPsec tunnel is transparent to WLAN infrastructure
There are no standardized network interfaces in LWIP
Single IPSec tunnel per UE for UL and DL data
MME / S - GW 1
WLAN
eNB UE I P
LWIP-SeGW

66. LWIP Protocol Architecture
IP packets transferred between the UE and LWIP-SeGW are encapsulated using IPsec
Provide security to the packets that traverse WLAN
Uplink and downlink data supported over WLAN
Multiple bearers can be offloaded via IPSec

67. Bearer over LWIP Tunnel - Protocol Stack
The data bearer refers to the EPS bearer mapped to the Data Radio Bearer (DRB) which is maintained on the LTE side
The DRB configuration on the LTE access corresponding to the data bearer using IPsec resources shall not be released
A single IPSec tunnel is used per UE for all the data bearers that are configured to send and/ or receive data over WLAN
Each data bearer may be configured so that traffic for that bearer can be routed over the IPsec tunnel in either only downlink or both uplink and downlink over WLAN
The RRC_Connection_Reconfiguration message provides the necessary parameters for the UE to initiate the establishment of the IPSec tunnel for the DRB

68. LTE-WLAN Aggregation (LWA) (TS36.300/22A)
E-UTRAN supports LWA operation whereby a UE in RRC_CONNECTED is configured by the eNB to utilize radio resources of LTE and WLAN
WLAN AP/AC only interacts with eNB; no interaction with the Core Network
LWA is controlled by eNB, based on UE measurement reporting
When LWA is activated, eNB configures one or more bearers as LWA bearers
Two scenarios are supported depending on the backhaul connection between LTE and WLAN
Collocated LWA scenario for an ideal/internal backhaul
Non-collocated LWA scenario for a non-ideal backhaul
WLAN Termination (WT) terminates the Xw interface for WLAN
C-Plane connectivity of eNB and WT for LWA
U-Plane connectivity of eNB and WT for LWA

69. LWA Radio Protocol Architecture
In LWA, the radio protocol architecture that a particular bearer uses depends on the LWA backhaul scenario and how the bearer is set up
Two bearer types exist for LWA: split LWA bearer and switched LWA bearer
LWA Radio Protocol Architecture for the Collocated Scenario
LWA Radio Protocol Architecture for the Non-Collocated Scenario
LWA allows a single bearer to be configured to utilize LTE and WLAN simultaneously
Split and switched bearers are supported
R13 LWA supports aggregation in downlink only, while uplink transmission is always on LTE
Packets (PDCP PDUs) belonging to LWA bearer can be sent by eNB via LTE or WLAN simultaneously
LWA uses EtherType 0x9E65 allocated by IEEE RAC

70. Enhanced LWA (eLWA) Uplink data transmission on WLAN
Including uplink bearer switch and bearer split (RAN2)
Mobility optimizations
e.g. intra and inter eNB handover without WT change and improvements for Change of WT (RAN2, RAN3)
Potential enhancements to support
60 GHz new band and channels (e.g. in measurements) and
increased data rates for ax, ad, and ay (e.g. by PDCP optimizations) (RAN2, RAN3)
Additional information collection and feedback
e.g. for better estimation of available WLAN capacity (by additional signaling on both Uu and Xw) to improve LWA performance (RAN2, RAN3)
Automatic Neighbour Relation (ANR) for LWA
e.g. for discovery of WLANs under eNB coverage (RAN3, RAN2)
Reference: Rel-14 eLWA Work Item Description (WID) - RP

71. LTE-U/LTE-LAA
LTE-U (LTE-Unlicensed), or as it is also known LTE-LAA (LTE-License Assisted Access) utilizes unlicensed spectrum, typically in the 5GHz band to provide additional radio spectrum
First introduced in Rel13
Built upon carrier aggregation capability of LTE-A
No changes are needed to the core network
Three ways of deployed
Downlink only
Uplink and downlink
FDD / TDD aggregation
The use of carrier aggregation mixes between FDD and TDD

72. Comparison of LTE and Wi-Fi
Comparison between LTE and Wi-Fi in the PHY/MAC layers
LTE Wi-Fi

73. Licensed-Assisted Access (LAA)
LTE in unlicensed spectrum serves as an additional tool to maximize the value for users, while the core of the activity remains anchored to the licensed spectrum
The primary component carrier in licensed spectrum will still be used to carry some (or all) of the control signal (and possibly also data, e.g. retransmissions) of the traffic carried over the carrier in unlicensed spectrum
Unlicensed spectrum is better used as “Licensed-Assisted Access”, considered as a secondary component carrier in a carrier aggregation scenario
The use of unlicensed spectrum also increases the need for more licensed spectrum
Define 5 GHz unlicensed LAA band or bands within frequency limits 5150 – 5925 MHz
The PHY layer options considered for LAA have at least the following characteristics
Support for at least 20 MHz system BW option in the 5 GHz band
System bandwidths < 5 MHz are not considered for PHY layer options in LAA
Potential interference sources
IEEE (a, n, ac)
Weather radar

74. LTE-unlicensed Operation Modes

75. LTE-advanced Aggregation Between FDD and TDD Bands

76. LAA Deployment Scenarios (R13 TR36.889)
Scenario 1: CA between licensed macro cell (F1) and unlicensed small cell (F3)
Scenario 2: CA between licensed small cell (F2) and unlicensed small cell (F3) without macro cell coverage
Scenario 3: Licensed macro cell and small cell (F1), with CA between licensed small cell (F1) and unlicensed small cell (F3)
Scenario 4: F1 + F2 + F3 - CA between licensed SC (F2) and unlicensed SC (F3)
- CA between macro cell (F1), licensed SC (F2) and unlicensed SC (F3) if ideal backhaul between macro and small cells

77. Coexistence Scenarios
The coexistence between Wi-Fi and LTE-U
The coexistence between LTE-Us of different operators

78. Design Targets of an LAA System
A single global solution framework allowing compliance with any regional regulatory requirements
A single global solution framework for LAA should be defined to ensure that LAA can be operated according to any regional regulatory requirements
Furthermore, LAA design should provide sufficient configurability to enable efficient operation in different geographical regions
Effective and fair coexistence with Wi-Fi
The LAA design should target fair coexistence with existing Wi-Fi networks to not impact Wi-Fi services more than an additional Wi-Fi network on the same carrier, with respect to throughput and latency
Effective and fair coexistence among LAA networks deployed by different operators
The LAA design should target fair coexistence among LAA networks deployed by different operators so that the LAA networks can achieve comparable performance, with respect to throughput and latency

79. Functionalities Required for an LAA System
Listen-Before-Talk (LBT)
Applying a clear channel assessment (CCA) check before using the channel
Energy detection (at least 20 us) to determine presence or absence of other signals
Discontinuous transmission on a carrier with limited maximum transmission duration
4ms in Japan
Dynamic frequency selection (DFS) for radar avoidance in certain bands/regions
Carrier selection for low interference and good co-existence
Transmit Power Control
Able to reduce the transmit power in a proportion of 3dB or 6dB
RRM measurements including cell identification
Enabling mobility between SCells and robust operation in the unlicensed band
Automatic Gain Control (AGC) setting
Coarse synchronization
Fine frequency/time estimation at least for demodulation
Channel-State Information (CSI) measurement, including channel and interference

80. Listen-Before-Talk (Clear Channel Assessment)
The listen-before-talk (LBT) procedure is defined as a mechanism by which an equipment applies a clear channel assessment (CCA) check before using the channel
The CCA utilizes at least energy detection to determine the presence or absence of other signals on a channel in order to determine if a channel is occupied or clear, respectively
European and Japanese regulations mandate the usage of LBT in the unlicensed bands
Apart from regulatory requirements, carrier sensing via LBT is one way for fair sharing of the unlicensed spectrum and hence it is considered to be a vital feature for fair and friendly operation in the unlicensed spectrum in a single global solution framework

81. Licensed Shared Access (LSA)
A system architecture for operation in the 2300 MHz MHz band (April 2017)
Describe the interface between the NM (Network Manager) and LC (LSA Controller)
ETSI TS / ETSI TS / ETSI TS / ETSI TR
Aimed at enabling access for mobile/fixed communication networks (MFCNs) in those countries
Where access to the band is foreseen but cannot be provided without restrictions due to incumbent usage
National Regulatory Authority
LSA Repository

82. Summary Advances of wireless networks: A Unified Heterogeneous Network
Fundamental Technologies
Aggregating more channels: LTE-CA
Interference management: ICIC
Coordinated transmission: CoMP
Advanced Technologies
Aggregating unlicensed bands: LTE-U/LTE-LAA/LTE-LSA
Link-layer aggregation: LWA
IPsec Tunneling: LWIP
ANDSF and RCLWI