Design and Performance Analysis for radio planning

network

SupervisorsSupervisorsAssistant Prof.. Sherif Elsayed

KishkEng. Fahmy A. Khalifa

By /Eng Ahmed Hamed

Department of Electronics and Department of Electronics and CommunicationCommunication

Faculty of Engineering Faculty of Engineering Mansoura UniversityMansoura University

20082008

Contents

Project Motivation. UMTS Architecture. UMTS Issues. System Model and Assumptions. Uplink Admission and Handoff Procedure. Simulation Results. summary.

Project Motivation

UMTS system is considered as one of the most common 3G standards.

UMTS capacity is interference based , so its important to reach optimum design to get best performance.

Project Motivation

Project Motivation (cont’d)

Objective:How to build the program to design and simulate radio planning system.

Performance Metrics:The total system capacity.Probability of ongoing calls being dropped.Probability of incoming calls being blocked.

UMTS Architecture

UMTS Architecture

• System Features The UMTS operates in two modes FDD and

TDD.

UMTS Architecture (cont’d)• The UMTS architecture at the very highest level:

– User Equipment (UE).– UMTS Terrestrial Radio Access Network (UTRAN).

– Core network.

UMTS Architecture (cont’d) UMTS Subscriber Identity

Module (USIM) . Mobile Terminal (ME). Node B. Radio Network Controller (RNC). Mobile Switching Center (MSC). Home Location Register (HLR). Visitor Location Register (VLR).

Equipment Identity Register (EIR).

Authentication Center (AUC). GGSN (Gateway GPRS Support

Node). SGSN (Serving GPRS (General

Packet Radio Service) Support Node).

Gateway MSC.

User Equipment (UE)UE consist of two parts: Mobile Terminal (Handset)

_max output power of 2W. UMTS Subscriber Identity

Module (USIM) is a smart card that stores information about the subscriber such as:

MSISDN: Mobile Station Integrated Service Data Network.

IMSI: International Mobile Subscriber Identity.

TMSI: Temporary Mobile Subscriber Identity.

IMEI: International Mobile Equipment Identity.

UMTS Terrestrial Radio Access Network (UTRAN)

Radio Network Controller (RNC)

Serving and Drift RNCs

Core Network Architecture

Interfaces• A InterfaceThis interface exists between the MSC and the BSC and it is a pure GSM interface.

• Iu InterfaceThis interface connects the core network and the UMTS Radio Access Network.• Iub InterfaceThis interface is situated between the RNCand the Node B in the UTRAN.

• Iur InterfaceThe Iur interface connects two radio network controllers.• Gb InterfaceThe Gb interface connects the packet-

switched core network to the GSM network.

Interfaces cont.

MAP InterfacesTypes of MAP Interfaces:

Gf : fraud interface. Gp : PLMN interfaceGn : node interface . Gb : base interface.Gi :Internet interface. Gc : context interface.

UMTS Issues

Channels Types

Power Control

Handoff

Physical ChannelsPhysical Channels

Dedicated ChannelsDedicated Channels Common ChannelsCommon Channels

UMTS ChannelsUMTS Channels

transport Channelstransport Channels

Physical Channels:Physical Channels:carrier frequency, code, relative phase

Main 3G Requirements on Physical Layer:Main 3G Requirements on Physical Layer:

High bit rates up to 2 MbpsBandwidth-On-Demand = Flexible variable bit rateHigh spectral efficiency, especially in downlink

Tasks of physical layer:Error protection and detection.Control soft handover and power control.Mapping transport ch to physical ch.

Uplink Physical Channels

Dedicated uplink physical channels Common Uplink physical channels

Downlink physical channel

Dedicated physical channels Common physical channels

Frame Structure for Uplink DPDCH/DPCCH

PRACH – Physical Random-Access Channel. PRACH is used to carry RACH.

Access Slots

Frame Structure for Downlink DPCH

DPCH – Dedicated physical channels

CCPCH – Primary Common Control Physical Channel

Frame Structure for primary Common Control physicalChannel

Frame Structure for Secondary Common Control physical Channel

CCPCH – secondary Common Control Physical Channel

This channel is used by mobile stations for cell search. There are two synchronization channels _the primary and the secondary.

The primary synchronization channel transmits a modulated code, called the primary synchronization code.Every cell in a UTRAN uses the same primary synchronization code.The secondary SCH is constructed by repeating a sequence of modulated codes of 256 chips and is transmitted in parallel with the primary SCH.

Transport Channel to physical Channel Mapping

Transport channels:Transport channels:They are defined on the basis of the types of

information they transfer and how it is transferred

on the radio interface.

Dedicated Transport Channels:-DCH – Dedicated Channel DCH

Full douplex channel.carry control information between the network and mobile station .It controls (call setup, billing, handover, power,……)

SDCCH – Stand-Alone Dedicated Control Channel Full douplex channel.Used for service requests.Initiate call setup.

DTCH – Dedicated Traffic ChannelFull douplex channel

During call setup the network takes the SDCCH and gives the DTCH to the subscriber to can send speech or data.

Common Transport Channels:-Broadcast Channel (BCH) :

D.L transport channel. cell-specific parameters such as random access codes, access slots in a cell, or diversity types used. carries UTRAN system.

Paging Channel (PCH):D.L transport channel .To inform the subscriber of an incoming call.

Random Access Channel (RACH):U.L transport channel, available only in the FDD mode. Used to request a channel for a connection.

Forward Access Channel (FACH):D.L transport channel.It carries control information to terminals known to be located in the given cell .(Ack)

Other Transport Channels:-

Common Packet Channel (CPCH)uplink transport channel .carry packet data from a user.

Downlink Shared Channel (DSCH)downlink transport channel.carries user data and control information.

Uplink Shared Channel (USCH)only used in the TDD mode. carry both control and user data.

Power Control in UMTSPower control is very important for UMTS :Power control is very important for UMTS :• Minimize the interference in the system.• All signal arrives at base station’s receiver with the same signal power.• Solve Near-far problem.

Near-far effect in the up link direction

Power Control in UMTS

Types of power control:Types of power control:A. Open loop power control

B.B. Closed loop power control

C.C. Inner loop power control

Handover

Is the process in which a cellular phone is handed from one cell to the next in order to maintain a radio connection with the network. Types of Handover:

• Hard Handover (GSM).• Soft Handover (UMTS).• Softer Handover (Sectors).

Admission Control (AC)

• Admission Control occurs when new connection is set up as well as handover.

• Ac needs to check that admittance will not sacrifice the planned coverage area or existing connection.

Admission Control (AC)Ac algorithm estimates the load that the

establishment of the bearer would cause in the network.

Load Control (Congestion Control)

• It’s important to ensure that system is not overloaded and remains stable.• The possible load control actions in order to reduce load• DL fast load control (deny DL power up

command).• UL fast load control (reduce the Eb/No

target). • Handover to another WCDMA carrier.• Decrease bit rates of real time UE’s.

Load Control (Congestion Control)

HSPA

• High Speed Downlink Packet Access.• High Speed Uplink Packet Access. • HSOPA.

Technological approach

Reasons to deploy HSDPA:• Saturated voice

communication market• Growing demand and user

expectation for the data services like broadband internet access, streaming, gaming, etc.

• Competing High Speed wireless technologies:

- WLAN - WiMAX

Shorter time transmission interval (TTI)• HSDPA introduces short TTI concept,

where TTI=2ms.• Advantages: -Less probability of an error due to the

change of the channel conditions . -More efficient when packet retransmission

is necessary. -Decreased buffer size.• ARQ mechanism is placed in RNC(Rel’99): -Disadvantage: latency time up to 100 ms! -Solution: move it to node B. -Profit: latency below 10 ms• Scheduling is controlled by RNC(Rel’99): -Disadvantage: important channel

measurement information can be delayed. -Solution: move scheduling close to the air

interface. -Profit: rescheduling is made within a short

time.

Adaptive Modulation and Coding (AMC)

• Main principle –to dynamically modify Signal modulation and Coding scheme to compensate the variations in cannel conditions.

• Benefits: -Increased average cell

throughput -Reduced interference

variation -Higher data rates for users

in favourable positions.

HARQ

H-ARQ-type-IIIH-ARQ-type-II

Channel

Category Max. no of codes

Modulation Max. data rate[Mbit/s]

1 5 QPSK & 16-QAM 1.2

2 5 QPSK & 16-QAM 1.2

3 5 QPSK &16-QAM 1.8

4 5 QPSK &16-QAM 1.8

5 5 QPSK &16-QAM 3.6

6 5 QPSK &16-QAM 3.6

7 10 QPSK &16-QAM 7.3

8 10 QPSK &16-QAM 7.3

9 15 QPSK &16-QAM 10.2

10 15 QPSK &16-QAM 14.4

11 5 QPSK only 0.9

12 5 QPSK only 1.8

HSUPA

• To enhance the uplink performance.

• The key difference between uplink and downlink is the handling of the total transmission power resource.

• The power control cannot be abandoned in the case of continuous uplink transmission due to the near–far problem.

HSOPA

• OFDM divides the signal into several narrow-band sub-carriers which are designed to be narrower than the coherence bandwidth of the wireless propagation channel.

• Uses Orthogonal Frequency Division Multiplexing (OFDM) and multiple-input multiple-output (MIMO) antenna.

• Flexible bandwidth usage with 1.25 MHz to 20 MHz bandwidths. By comparison, W-CDMA uses fixed size 5 MHz chunks of spectrum.

• HSOPA will use OFDMA for the down-link and Single Carrier FDMA (SC-FDMA) for the up-link, WiMAX/802.16e-2005 uses OFDMA for both the up and down links.

• For WiMax, HSDPA serves as a form of competition that's not as fast. WiMax promises speeds of up to 70Mbps, but much more mobile.

• HSDPA will allow to increase downlink throughput and, in turn, offer advanced quality of service (QoS) capabilities and speeds that rival those delivered by cable modem and DSL service providers.

Simulation

system considerations The program is initiated by a number of

usersRandom uniform velocity distribution Vt , Uniform random directions 0→2π, Uniform random locations (X,Y), Uniform random call duration Ct Number of the serving base station and

the corresponding path gain PgThe call arrival rate to the system is considered

to be a Poisson distributed random variable with mean (L)

System model

Cell membershipPath Gain Criterion.

Users select the base station to Users select the base station to which it has the largest path gainwhich it has the largest path gain

Cell Load CriterionUsers select the base station with Users select the base station with

the smallest number of users.the smallest number of users.

System model

Each cell supplies coverage and service to a specific number of users.

Users (MS) are uniformly distributed within the unit areas.

Only the uplink is considered.The system performance is determined

by a constraint on the Signal-to-Interference Ratio (SIR) at all BSs.

A threshold value of SIR for all users in the system is required to maintain the acceptable QoS.

System model Each user in the environment is processed

by only one BS.

Cell membership is determined according to the path gain.

The system employ perfect uplink power control

(That is mean the received signal power from all users in the system is the same

Uplink Performance

n

trd

dokPP

Propagation Model

Simplified Propagation Model

010 4

log20)(d

dBk

Uplink Performance

outcellincellP

Gr

IIN

PSSIR

bG R

W

atedata

ratechipP

r

The uplink SIR

Where Sr is the received signal power. PG is the system processing gain. Np is Background Noise power

Iincell is the in-cell interferenceIoutcell is the out-of-cell interference

Uplink admission and handoff

Users select base station according to a predefined path gain criteria

New call requests as well as the handoff requests are queued (one second length queue)

A new user will be admitted as long as its SIR is above the systems’ SIRmin and those of all users are also above the minimum threshold

Handoff requests are prioritized than new call requests

[Flowchart]

Simulation result

System capacity

Blocking of new user