antenna selection

8/10/2019 Antenna Selection

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The only time a Tata Indicom Phone wont be accessible.

Please switch off your mobile phones during the presentation.

Confidential

CDM B SICS


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C LL FLOW IN CDM


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Performance Management Terminology (cont.)

OriginationMessageTxfro

mMS

or

G

eneralPageTxfromB

S

O

riginationMessageRx

atBS

or

PageResponseRxat

BS

ChannelAssignmentMe

ssage

TxfromBS

ServiceConnectCom

plete

MessageRxatB

S

CallConnectivit

yLost

Admission Connection Service

Blocked Call Setup Failure Dropped Call

Access Failure


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H NDOFF IN CDM


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Handoff process

When a MS is moving from one cell to another, the MS undergoes procedures,

called handoff, that allow the MS to acquire the pilot channel transmitted by

neighboring BTS and to make another connection to a new BTS, while

maintaining a connection to the old base station transceiver system (BTS).

To perform a handoff process, every MS measures and internally stores the information about

neighboring Forward Pilot Channels (FPiChs) acquired in its current location.


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Active set

Pilots of CDMA carriers whose forward paging channels of Forward Common Control Channels

(FCCChs) are being monitored while in idle state.During a call, these are the pilots associated with forward traffic channels assigned to the MS.

Candidate set

Pilots not currently in the active set but with enough signal power level to become an active pilot.

Neighbor set

Pilots that do not belong to the active or candidate sets but may also be considered candidates for ahandoff process

Remaining set

All remaining pilots that do not belong to any of the other sets but are in the area where the MS is

located;

Handoff Pilot Sets


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Soft handoff

A soft handoff is applied to an MS that starts communication with a new BTS while still

connected to another BTSMake-before-break

Hard handoff

A MS is disconnected from one BTS and is switched to another

Break-before-make

Softer handoffA special soft handoff between sectors in the same BTS

Idle handoff

An idle handoff is performed while in idle state when the MS is moving from one BTS to

another

Access handoffAn access handoff occurs in the system access state when the MS is performing access

attempts.

Handoff Types


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FERis the most common network quality parameter to execute power control

Ec/Io (ratio of chip energy, Ec, to interference plus noise spectral density)

Eb/Io (ratio of bit energy, Eb, to interference plus noise spectral density)

Power control aims to quickly and efficiently estimate the minimum MS transmission

power to achieve the required communication quality (based on FER statistics)

Benefits of power control in CDMA systems

Increase in system capacity

Minimization of near-far effect

Increase in battery lifetime

Power Control


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Open loop power control

Usually implemented as the initial power control to give an estimate of minimum

transmission power used for access channels, such as Reverse Access Channels

(RAChs), Enhanced Access Channels (EAChs), and Reverse Common Control

Channels (RCCChs), during system access state.

Closed loop power control

Usually implemented for traffic channels, which need a more sophisticated power

control system. cdma2000 systems can also employ this type of power control

even during the system access state.


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Procedure of the closed loop power control

A) An MS initially uses the transmission power defined in the last message from

last access probe transmitted on the system access state.

B) The BTS determines a set point power level, which is considered ideal for

receiving signals within a certain QoS.

C)The set point is periodically adjusted.

D) The BTS performs power control by transmitting power control bits, which

instruct MSs individually to increase or reduce transmission power according to

the estimated set point value.


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TH NK YOU

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