Upload
yasser-monier
View
158
Download
1
Embed Size (px)
DESCRIPTION
Dual Carrier HSPA and Carrier Aggregation with a small comparison of the different mobile technologies architecture GSM, UMTS, and LTE.
Citation preview
Cellular Communication
Systems
***The Inside Story
Contents
Main Issues (Resources,
Capacity, Access, etc.)
Concepts Of Wireless
Communication
2G, 3G, LTE Topologies
DC-HSPA
Contents
Main Issues (Resources,
Capacity, Access, etc.)
Concepts Of Wireless
Communication
2G, 3G, LTE Topologies
DC-HSPA
Addresses how the overall resource (time, frequency and
space) of the system is shared by the users in the same cell
(intra-cell)
Addresses the interference caused by simultaneous signal
transmissions in different cells (inter-cell)
Two main issues in cellular communication: multiple access and interference management
Main Issues (Resources,
Capacity, Access, etc.)
Multiple Access
Interference
Management
Time Division Duplex:
separates the transmissions in time
Frequency Division Duplex:
separates the transmissions in frequency
In addition, there is also an issue of how the resource is allocated between the uplink (the reverse link) and the downlink (the forward link). DUPLEXING
Main Issues (Resources,
Capacity, Access, etc.)
TDD
FDD
A cellular network provides coverage of the entire area by dividing it into cells.
Main Issues (Resources,
Capacity, Access, etc.)
Contents
Main Issues (Resources,
Capacity, Access, etc.)
Concepts Of Wireless
Communication
2G, 3G, LTE Topologies
DC-HSPA
Intelligent allocation and reuse of channels throughout a coverage region.
A set of radio channels for each base station, cell.
Adjacent cells: completely different channels
Same group of channels may be used to cover different cells that are separated from one another to keep interference levels within tolerable limits
Frequency Reuse
Concepts Of Wireless
Communication
When a mobile moves into a different cell while a conversation is in progress, the call is transferred to a new channel belonging to the new base station.
Points To Consider:A. Hard handover VS. Soft handovers
Handovers
Concepts Of Wireless
Communication
A major limiting Factor
Sources : mobile in the same cell, a call in progress in a neighboring cell, or other base stations operating in the same frequency band.
A. Co-channel Interference
B. Adjacent Channel Interference
Interference and System Capacity
Concepts Of Wireless
Communication
Demand goes up
The number of channels insufficient.
Design techniques to provide more.
Cell splitting and sectoring.
Improving Coverage and Capacity in Cellular Systems
Concepts Of Wireless
Communication
Cell splitting is the process of subdividing a congested cell into smaller cells
Cell Splitting
Concepts Of Wireless
Communication
Dividing a cell into three (or six) equal-space sectors using directional antennas.
The channels used in a particular cell are broken down into sectored groups and are used only within a particular sector
Increasing the frequency reuse.
Cell Sectoring
Concepts Of Wireless
Communication
Hard-to-reach areas: within buildings, or in valleys or tunnels.
Radio re-transmitters, known as repeaters, are often used to provide such range extension capabilities.
Repeaters for Range Extension
Concepts Of Wireless
Communication
MULTIPLE ACCESS TECHNIQUES
Allow many mobile users to share simultaneously a finite amount of radio spectrum.
Mobiles are Mobile ---- No easy way ---- More penetration ----More valuable is the spectrum ---- Role Of Multiple Access
Points To Consider:A. Duplexing
B. High capacity is required.
C. NO severe degradation in the performance.
Multiple Access
Three major techniques:
A. Frequency division multiple access (FDMA)
B. Time division multiple access (TDMA)
C. Code division multiple access (CDMA)
Others:
A. Orthogonal Frequency Division Multiple Access (OFDM)
Techniques
Multiple Access
Contents
Main Issues (Resources,
Capacity, Access, etc.)
Concepts Of Wireless
Communication
2G, 3G, LTE Topologies
DC-HSPA
The GSM network can be divided into following broad parts:
** The Mobile Station (MS)** The Base Station Subsystem (BSS)** The Network Switching Subsystem (NSS)
2G -GSM
First Introduction Of DATA….
Same network + some changes
Mobile Station (MS)New Mobile Station is required to access GPRS services. These new terminals will be backward compatible with GSM for voice calls.
GPRS Support Nodes (GSNs)Installation of new core network elements : the serving GPRS support node (SGSN) and gateway GPRS support node (GGSN).
The BTS, BSC, HLR, VLR needed only software upgrades.
GPRS
SGSN = Serving GPRS Support Node, GGSN = Gateway GPRS Support Node, and GR = GPRS Register.
From a GSM/GPRS network, the following network elements can be reused:
(HLR) --- (VLR) --- (EIR) --- (MSC) --- (AUC) --- (SGSN) --- (GGSN)
From a GSM/GPRS communication radio network, the following elements cannot be reused:
Base station controller (BSC)Base transceiver station (BTS)
**Remain, Dual network operation, 2G/3G co-exist
Migrating from GSM/GPRS to UMTS
3G -UMTS
The UMTS network introduces new network elements that function as specified by 3GPP:
NODE B : WCDMA--- Frequency use (the whole network can use a single frequency pair)/ Power requirements.
Radio Network Controller (RNC) : mainly control the NODE Bsand their power levels.
Migrating from GSM/GPRS to UMTS … Cont’d
3G -UMTS
The Quest For More:
More Spectrum
More Capacity
More Small Cells
More Speed (D&U)
More Business Solutions
More Consistency
And Less COSTS
More Users
More Market
Penetration
And Less COSTS
Peak download rates up 300 Mbit/s and upload rates up to 75 Mbit/s
MIMO (with 2×2 / 4×4 antennas using up to 20 MHz of spectrum).
The LTE standard supports only packet switching with its all-IP network --- Global Roaming
Improves call set-up time.
Higher data-carrying capacity and a higher spectral efficiency.
Lowers the cost-per-bit.
Increase the efficiency of entire network.
Operations easier and less expensive to manage.
WHY
LTE
It uses OFDMA radio-access for the downlink and SC-FDMA on the uplink
EUTRAN consists only of ENODEBs on the network side.
The ENODEB performs tasks similar to those performed by the NODEBs and RNC (radio network controller) together in UTRAN.
The aim of this simplification is to reduce the latency of all radio interface operations.
LTE’s Radio Access Network (EUTRAN) : Evolved UMTS Terrestrial Radio Access
LTE
Evolved Packet Core Network
LTE
* Flat architecture, avoid protocol conversion.
* Separate the user data and the signaling
Very basic architecture of the EPS
LTE EPS
LTE
Contents
Main Issues (Resources,
Capacity, Access, etc.)
Concepts Of Wireless
Communication
2G, 3G, LTE Topologies
DC-HSPA
3 Source: www.gsacom.com , Feb 2014
547HSPA NETWORKS IN 205 COUNTRIES
363HSPA+ NETWORKS IN 157 COUNTRIES
160DUAL-CARRIER NETWORKS IN 83 COUNTRIES
HSPA+: Building upon the solid global foundation
9
HSPA+ Dual-carrier is main-stream Supporting 42 Mbps downlink peak data rate
Deployment of 42 Mbps DC-HSPA+ technology continues as the major trend in 2014 – GSA, Mar 2014
160 NETWORKS
83 COUNTRIES
Countries launched/committed to Dual-carrier
Source: www.gsacom.com , Feb 2014
HSPA & WCDMA : A True Success
Enhancements and new features : HSPA+, 3GPP rel. 8 to 10
Data rates .. Spectral efficiency .. Latency in the system
DUAL CARRIER-HSDPA
How It Works
How It Works
HSPA Additional Channels:
WHY: Provide the additional data capacity, the control required.
In addition to the existing 3G UMTS channels.
DUAL CARRIER-HSDPA
How It Works
High Speed Downlink Shared Channel, HS-DSCH** Data transport channel.
High Speed Signaling Control Channel, HS-SCCH** Control Channel: Carries elements of info.** Signal the scheduling to the users.
High Speed Dedicated Physical Control Channel, HS-DPCCH
** Feedback to the scheduler.** Located in the UL.
DUAL CARRIER-HSDPA
How It Works
Carrier Aggregation ** 2 Engines in one car, driving with doubled rate
in the DL.
** DC-HSPA: Two adjacent DL carriers (5 MHz) + one UL .. Peak rates D: 42 Mbps
** Scheduling and coordination:
-NODEB’s Scheduler.
-One HS-SCCH for each 5 MHz carrier.
-Decisions based on CQI (Channel quality info.) feedback.
SO How It Works
10
Dual-carrier – Delivering high data rates in real networks
>5Mbps >50%
Source: Signals Research Group Signals Ahead, September 2011, “The Mother of all Network Benchmark Tests”
0 – 0.25Mbps 8.6%
0.25 – 0.5Mbps 4.8%
0.5 – 1Mbps 8.1%
1 – 1.5Mbps 6.5%
1.5 – 2Mbps 4.6%
2 – 2.5Mbps 3.8%
2.5 – 5Mbps 11.4% 5 – 7.5Mbps
9.9%
7.5 – 10Mbps 8.8%
10 – 12.5Mbps 8.7%
12.5 – 15Mbps 10.6%
15 – 20Mbps 14.1%
>1Mbps ~80%
USER DATA RATE OF THE TIME
Based on comprehensive benchmarking tests conducted across two operators in greater Dallas area (Texas), covering more than 23 miles of
driving, downloading nearly 7GB of data
USER DATA RATE OF THE TIME
ThanksFor
Listening
BIBLIOGRAHY:
• ITU (International Telecommunication Union)
• Ericsson, QUALCOMM, and Alcatel-Lucent White Papers.
• The 3rd Generation Partnership Project (3GPP) Releases.
• Rohde-Schwarz• Radio-Electronics.com