CHAPTER 7. How to Download………………………………………………………………..…..??
APPENDIX……………………………………………………………………………………….…..60
LG Electronics Inc.
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LG-TM250
General Introduction
The LG-TM250 phone has been designed to operate on the latest digital mobile communication technology,
Code Division Multiple Access (CDMA). This CDMA digital technology has greatly enhanced voice clarity and
can provide a variety of advanced features. Currently, CDMA mobile communication technology has been
commercially used in Cellular and Personal Communication Service (PCS). The difference between them is the
operating frequency spectrum. Cellular uses 800Mhz and PCS uses 1.9Ghz. The LG-TM250 support GPS Mode,
we usually call it tri-band phone.
The CDMA technology adopts DSSS (Direct Sequence Spread Spectrum). This feature of DSSS enables the
phone to keep communication from being crossed and to use one frequency channel by multiple users in the
same specific area, resulting that it increases the capacity 10 times more compared with that in the analog mode
currently used. Soft/Softer Handoff, Hard Handoff, and Dynamic RF power Control technologies are combined
into this phone to reduce the call being interrupted in a middle of talking over the phone.
Cellular and PCS CDMA network consists of MSO (Mobile Switching Office), BSC (Base Station Controller),
BTS (Base station Transmission System), and MS (Mobile Station). The following table lists some major
CDMA Standards.
CDMA Standard Designator Description
Basic air interface TIA/EIA/IS-95-A/B/C
ANSI J-STD-008
Network TIA/EIA/IS-634
TIA/EIA/IS/651
TIA/EIA/IS-41-C
TIA/EIA/IS-124
Service TIA/EIA/IS-96-B
TIA/EIA/IS-99
TIA/EIA/IS-637
TIA/EIA/IS-657
Protocol between MS and BTS for Cellular
Protocol between MS and BTS for PCS
MAS-BS
PCSC-RS
Intersystem operations
Nom-signaling data comm.
Speech CODEC
Assign data and fax
Short message service
Packet data
Performance TIA/EIA/IS-97
TIA/EIA/IS-98
ANSI J-STD-018
ANSI J-STD-019
TIA/EIA/IS-125
* TSB –74: Protocol between an IS-95A system and ANSI J-STD-008
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Cellular base station
Cellular mobile station
PCS personal station
PCS base station
Speech CODEC
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LG-TM250
1. System Introduction
1.1 CDMA Abstract
The CDMA mobile communication system has a channel hand-off function that is used for collecting the
information on the locations and movements of mobile telephones from the cell site by automatically controlling
several cell site through the setup of data transmission routes, and then enabling one switching system to carry
out the automatic remote adjustment. This is to maintain continuously the call state through the automatic
location confirmation and automatic radio channel conversion when the busy subscriber moves from the service
area of one cell site to that of another by using automatic location confirmation and automatic radio channel
conversion functions. The call state can be maintained continuously by the information exchange between
switching systems when the busy subscriber moves from one cellular system area to the other cellular system
area.
In the cellular system, the cell site is a small-sized low output type and utilizes a frequency allocation system
that considers mutual interference, in an effort to enable the re-use of corresponding frequency from a cell site
separated more than a certain distance.
Unlike the time division multiple access (TDMA) or frequency division multiple access (FDMA) used in the
band limited environment, the Code Division Multiple Access (CDMA) system which is one of digital cellular
systems is a multi-access technology under the interference limited environment. It can process more number of
subscribers compared to other systems (TDMA system has the processing capacity three times greater than the
existing FDMA system whereas CDMA system, about 12~15 times of that of the existing system).
CDMA system can be explained as follows; TDMA or CDMA can be used to enable each person to talk
alternately or provide a separate room for each person when two persons desire to talk with each other at the
same time, whereas FDMA can be used to enable one person to talk in soprano, whereas the other in bass (one
of the two talkers can carry out synchronization for hearing in case there is a bandpass filter function in the area
of the hearer). Another available method is to make two persons to sing in different languages at the same time,
space, and frequency when wishing to let the audience hear the singing without being confused. This is the
characteristic of CDMA.
On the other hand, when employing the CDMA technology, each signal has a different pseudo-random binary
sequence used to spread the spectrum of carrier. A great number of CDMA signals share the same frequency
spectrum. In the perspective of frequency area or time area, several CDMA signals are overlapped. Among these
types of signals, only desired signal energy is selected and received through the use of pre-determined binary
sequence; desired signals can be separated, and then received with the correlator used for recovering the
spectrum into its original state. At this time, the spectrums of other signals that have different codes are not
recovered into its original state, and appears as the self-interference of the system.
LG Electronics Inc.
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LG-TM250
2. Features and Advantages of CDMA Mobile Phone
2.1 Various Types of Diversities
When employing the narrow band modulation (30kHz band) that is the same as the analog FM modulation
system used in the existing cellular system, the multi-paths of radio waves create a serious fad ing. However, in
the CDMA broadband modulation (1.25MHz band), three types of diversities (time, frequency, and space) are
used to reduce serious fading problems generated from radio channels in order to ob tain high-quality calls.
Time diversity can be obtained through the use of code interleaving and error correction code whereas frequency
diversity can be obtained by spreading signal energy to wider frequency band. The fading related to normal
frequency can affect the normal 200~300kHz among signal bands and accordingly, serious effect can be avoided.
Moreover, space diversity (also called path diversity) can be realized with the following three types of methods.
First, it can be obtained by the duplication of cell site receive antenna. Second, it can be obtained through the
use of multi-signal processing device that receives a transmit signal having each different transmission delay
time and then, combines them. Third, it can be obtained through the multiple cell site connection (Soft Handoff)
that connects the mobile station with more than two cell sites at the same time.
2.2 Power Control
The CDMA system utilizes the forward (from a base station to mobile stations) and backward (from the mobile
station to the base station) power control in or der to increase th e call p ro cessing capacity and ob tain h igh -q uality
calls. In case the originating signals of mobile stations are received by the cell site in the minimum call quality
level (signal to interference) through the use of transmit power control on all the mobile stations, the system
capacity can be maximized.If the signal power of mobile station is received too strong, the performance of that
mobile station is improved. However, because of this, the interference on other mobile stations using the same
channel is increased and accordingly, the call quality of other subscribers is reduced unless the maximum
accommodation capacity is reduced.
In the CDMA system, forward power control, backward open loop power control, and closed loop power control
methods are used. The forward power control is carried out in the cell site to reduce the transmit power on
mobile stations less affected by the multi-path fading and shadow phenomenon and the interference of other cell
sites when the mobile station is not engaged in the call or is relatively nearer to the corresponding cell site. This
is also used to provide additional power to mobile stations having high call error rates, located in bad reception
areas or far away from the cell site.
The backward open loop power control is carried out in a corresponding mobile station; the mobile station
measures power received from the cell site and then, reversely increases/decreases transmit power in order to
compensate channel changes caused by the forward link path loss and terrain characteristics in relatio n to the
mobile station in the cell site. By doing so, all the mobile transmit signals received by the base station have same
strength.
Moreover, the backward closed loop power control used by the mobile station is performed to control power
using the commands issued out by the cell site. The cell site receives the signal of each corresponding mobile
station and compares this with the pre-set threshold value and then, issues out power increase/decrease
commands to the corresponding mobile station every 1.25msec (800 times per second). By doing so, the gain
tolerance and the different radio propagation loss on the forward/backward link are complemented.
LG Electronics Inc.
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LG-TM250
2.3 Voice Encoder and Variable Data Speed
The bi-directional voice service having variable data speed provides voice communication which employs
voice encoder algorithm having power variable data rate between the base station and the mobile station. On the
other hand, the transmit voice encoder performs voice sampling and then, creates encoded voice packets to be
sent out to the receive voice encoder, whereas the receive voice encoder demodulates the received voice packets
into voice samples.
One of the two voice encoders described in the above is selected for use depending on inputted automatic
conditions and message/data; both of them utilize four-stage frames of 9600, 4800, 2400, and 1200 bits per
second for cellular and 14400,7200,3600,1800 bits per second for PCS, so PCS provide relatively better voice
quality (almost twice better than the existing celluar system). In addition, this type of va riable voice encoder
utilizes adaptive threshold values on selecting required data rate. It is adjusted in accordance with the size of
background noise and the data rate is increased to high rate only when the voice of caller is inputted.
Therefore, background noise is suppressed and high-quality voice transmission is possible under the
environment experiencing serious noise. In addition, in case the caller does not talk, data transmission rate is
reduced so that the transmission is carried out in low energy. This will reduce the interference on other CDMA
signals and as a result, improve system performance (capacity increased by about two times).
2.4 Protecting Call Confidentiality
Voice privercy is provided in the CDMA system by means of the private long code mask used for PN spreading.
Voice privacy can ve applied on the traffic channels only. All calls are initiated using the public long code mask
for PN spreading. The mobile station user may request voice privacy during call setup using the origination
message or page response message, and during traffic channel operation using the long code transition request
order.
The Transition to private long code mask will not be performed if authentication is not performed. To initiate a
transition to the private or public long code mask, either the base station or the mobile station sends a long code
transition request order on the traffic channel.
2.5 Soft Handoff
A handoff in which the mobile station commences communications with a new base station without interrupting
communications with the old base station. Soft handoff can only be used between CDMA channels having
identical freqeuncy assignments.
2.6 Frequency Re-Use and Sector Segmentation
Unlike the existing analog cellular system, the CDMA system can reuse the same frequency at the adjacent cell.
there is no need to prepare a separate frequency plan. Total interference generated on mobile station signals
LG Electronics Inc.
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LG-TM250
received from the cell site is the sum of interference generated from other mobile stations in the same cell site
and interference generated from the mobile station of adjacent cell site. That is, each mobile station signal
generates interference in relation to the signals of all the other mobile stations.
Total interference from all the adjacent cell sites is the ratio of interference from all the cell sites versus total
interference from other mobile stations in the same cell site (about 65%). In the case of directional cell site, one
cell normally uses a 120°sector antenna in order to divide the sector into three. In this case, each antenna is
used only for 1/3 of mobile stations in the cell site and accordingly, interference is reduced by 1/3 on the average
and the capacity that can be supported by the entire system is increased by three times.
2.7 Soft Capacity
The subscriber capacity of the CDMA system is flexible depending on the relation between the number of
users and service classes. For example, the system operator can increase the number of channels available for
use during the busy hour despite the drop in call quality. This type of function requires 40% of normal call
channels in the standby mode during the handoff, in an effort to avoid call disconnection resulting from the lack
of channels.
In addition, in the CDMA system, services and service charges are classified further into different classes so that
more transmit power can be allocated to high class service users for easier call set-up; they can also be given
higher priority of using hand-off function than the general users.
LG Electronics Inc.
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LG-TM250
3. Structure and Functions of tri-band CDMA Mobile Phone
The hardware structure of CDMA mobile phone is made up of radio frequency (RF) part and logic part. The
RF part is composed of Receiver part (Rx), Transmitter part (Tx) and Local part (LO). For the purpose of
operating on tri-band, It is necessary dual Tx path, tri Rx path, dual PLL and switching system for band
selection. The mobile phone antenna is connected with the frequency seperater which divide antenna
input/output signals between cellular frequency band (824~894 Mhz) and PCS frequency band
(1850~1990Mhz). Each separated path is linked with the cellular duplexer and PCS duplexer. Duplexer carrys
out seperating Rx band and Tx band. The Rx signals from the antenna are converted into baseband frequency by
the frequency synthesizer and frequency down converter. And then, passive SAW filter which is a band pass
filter for removing Tx interferer frequency. The baseband signals is converted into digital signals via
Analog-to-Digital Converter (ADC). In front of the ADC, switching system is required to choose which band
path should be open. The digital signals send to 5 correlators in each CDMA de-modulator. Of these, one is
called a searcher whereas the remaining 4 are called data receivers (fingers). Digitalized IF signals include a
great number of call signals that have been sent out by the adjacent cells. These signals are detected with
pseudo-noise sequence (PN Sequence). Signal to interference ratio (C/I) on signals that match the desired PN
sequence are increased through this type of correlation detection process, but other signals obtain processing
gain by not increasing the ratio. The carrier wave of pilot channel from the cell site most adjacently located is
demodulated in order to obtain the sequence of encoded data symbols. During the operation with one cell site,
the searcher searches out multi-paths in accordance with terrain and building reflections. On three data receivers,
the most powerful 3 paths are allocated for the parallel tracing and receiving. Fading resistance can be improved
a great deal by obtaining the diversity combined output for de-modulation. Moreover, the searcher can be used
to determine the most powerful path from the cell sites even during the soft han doff between the two cell sites.
Moreover, 3 data receivers are allocated in order to carry out the de-modulation of these paths. Output data that
has been demodulated changes the data string in the combined data row as in the case of original
signals(deinterleaving), and then, are demodulated by the forward error correction decoder which uses the
Viterbi algorithm.
Mobile station user information send out from the mobile station to the cell site pass through the digital voice
encoder via a mike. Then, they are encoded and forward errors are corrected through the use of convolution
encoder. Then, the order of code rows is changed in accordance with a certain regulation in order to remove any
errors in the interleaver. Symbols made through the above process are spread after being loaded onto PN carrier
waves. At this time, PN sequence is selected by each address designated in each call.
Signals that have been code spread as above are digital modulated (QPSK) and then, power controlled at the
automatic gain control amplifier (AGC Amp). Then, they are converted into RF band by the frequency
synthesizer synchronizing these signals to proper output frequencies.
Transmit signals obtained pass through the duplexer filter and then, are sent out to the cell site via the antenna.
LG Electronics Inc.
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LG-TM250
4. Specification
4.1 General Specification
4.1.1 Transmit/Receive Frequency Interval :
CELLULAR : 45 MHz
1)
2) PCS : 80 MHz
4.1.2 Number of Channels (Channel Bandwidth)
CELLULAR : 20 Channels
1)
2) PCS : 48 Channels
4.1.3 Operating Voltage : DC 3.2~4.1V
4.1.4 Battery Power Consumption : DC 3.7V
SLEEP IDLE MAX POWER
CELLULAR
PCS
0.8 mA 100~120mA 650 mA (24 dBm)
0.8 mA 110~130 mA 750 mA (24 dBm)
4.1.5 Operating Temperature : -30°C ~ +60°C
4.1.6 Frequency Stability
1) CDMA : ±0.5PPM
2) PCS : ±0.1PPM
4.1.7 Antenna : Stubby Type (Helical&Meander), 50 Ω
4.1.8 Size and Weight
1) Size : 80 * 44 * 22.8 mm
2) Weight : 88 g (Approximately with standard battery)
1) The Battery pack is keyed so it can only fit one way. Align the groove in the battery pack with the rail on the
back of the phone until the battery pack rests flush with the back of the phone.
2) Slide the battery pack forward until you hear a “click”, which locks the battery in place.
LG Electronics Inc.
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LG-TM250
CHAPTER 2. NAM Programming Method
(Inputting of phone numbers included)
1. NAM Programming Method
1. Press ‘menu’ + 0 + “000000”
2. Press ‘1’ or ‘Soft Key 1’ key for entering ‘Service Prg.’
● Usually pressing ‘Soft Key 1’ will save the change.
● To exit Service Program, press ‘END’ key.
2-1) ESN
You can only see the ESN number.
Press ‘Soft Key 1’ to go next NAM 1 items.
Press ‘Soft Key 2’ to edit A-key.
2-1-1) A-Key
You can edit the A-Key.
Press ‘Soft Key 1’ to save and go next NAM 1 items.
Press ‘Soft Key 2’ to go previous NAM 1 items.
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LG-TM250
2-2) NAM 1 Mobile Directory Number
You can edit NAM1 Mobile Directory Number.
Press soft key 1 to save and go next NAM 1 items.
Press soft key 2 to go previous NAM 1 items.
2-3) NAM 1 Mobile Identification Number
You can edit NAM1 MIN.
Press soft key 1 to save and go next NAM 1 items.
Press soft key 2 to go previous NAM 1 items.
2-4) NAM 1 Home SID
You can edit NAM1 Home SID.
Press ‘Soft Key 1’ to save and go next NAM 1 items.
Press ‘Soft Key 2’ to go previous NAM 1 items.
2-5) NAM 1 Name
You can edit NAM 1 Name.
Press ‘Soft Key 1’ to save and go next more NAM 1 items.
Press ‘Soft Key 2’ to go previous NAM 1 items.
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LG-TM250
2-6) More NAM 1 Programming
You can decide to edit more NAM 1 items.
Press ‘Soft Key 1’ to exit basic Service Programming.
Press ‘Soft Key 2’ to edit more extended NAM 1 items.
2-7) Security Code
You can edit Security Code.
Press ‘Soft Key 1’ to save and go next NAM 1 items.
Press ‘Soft Key 2’ to go previous NAM 1 items.
2-8) NAM 1 MCC
You can edit NAM 1 Mobile Country Code.
Press ‘Soft Key 1’ to save and go next NAM 1 items.
Press ‘Soft Key 2’ to go previous NAM 1 items.
2-9) NAM 1 True IMSI MCC
You can edit NAM 1 True IMSI MCC.
Press ‘Soft Key 1’ to save and go next NAM 1 items.
Press ‘Soft Key 2’ to go previous NAM 1 items.
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