LG LG-RD2750 User manual

LGE
LG
Electronics Inc.
Features of Mobile Subscriber Radio Handset
(LG-RD2750 Type)
1. Wave Type
•G7W
2. Frequency Scope
•Transmit Frequency : 824.820 ~ 848.190MHz
•Receive Frequency : 869.820 ~ 893.190MHz
3. Rated Output Power
•0.282W(24.5dBm)
4. Output Conversion Method : This is possible by correcting the key board channel.
5. Voltage and Current Value of Termination Part Amplifier(Catalogue included)
Mode Type Name Voltage Current Power
CDMA FC7113 3.7V 600mA 0.32W
6. Functions of Major Semi-Conductors
Classification Function
MSM6000-208Pin-FBGA Operation control and digital signal processing of the mobile station
FLASH MEMORY
(K8D3216UTC-TI07) Flash Memory (32Mbit) ▶Storing of the mobile station operation program
STATIC RAM
(K1S161611A-FI70) SRAM (16Mbit) ▶Temporary storing of the data created while busy
RFT6122 & RFR6122 Converting baseband signal into Tx RF signal and Rx RF signal
into baseband signal
7. Frequency Stability
•±0.5PPM
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CDMA MOBILE SUBSCRIBER UNIT
LG-RD2750
SINGLE BAND
CDMA MOBILE PHONE
SERVICE MANUAL
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Table of Contents
General Introduction
............................................................................................................................................... 2
CHAPTER 1. System Introduction
1. System Introduction ................................................................................................................ 3
2. Features and Advantages of CDMA Mobile Phone .................................................................. 5
3. Structure and Functions of CDMA Mobile Phone ................................................................... 8
4. Specification .............................................................................................................................. 9
5. Installation ............................................................................................................................... 12
CHAPTER 2. NAM Input Method(Inputting of telephone numbers included)
1. Telephone Number and NAM Programming Method .............................................................. 14
CHAPTER 3. Circuit Description
1. RF Transmit/Receive Part ....................................................................................................... 17
2. Digital/Voice Processing Part .................................................................................................. 22
CHAPTER 4. Trouble Shooting
APPENDIX
Block Diagram
Circuit Diagram
Exploded View
Part Lists
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The LG-RD2750 cellular phone functions as digital cellular phone worked in CDMA (Code Division
Multiple Access) mode.
CDMA mode applies the DSSS (Direct Sequence Spread Spectrum) technique that has been used in
military. This technique enables to share one frequency channel with many users in the same specific
area. As a result, that it increases the capacity 10 times more compared with that in the analog mode
(AMPS) 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 phone.
CDMA digital cellular network consists of MSC (Mobile Switching Office), BSC (Base Station
Controller), BTS (Base station Transmission System), and MS (Mobile Station). Communication
between MS and BTS is designed to meet the specification of TIA/EIA/IS-95-A/B/C (Common Air
Interface). MS meets the specifications of the below :
- TIA/EIA/IS-95-A/B/C (Common Air Interface) : Protocol between MS and BTS
- TIA/EIA/IS-96-B : Speech CODEC
- TIA/EIA/IS-98 : Basic MS functions
- IS-126 : Voice loopback
- TIA/EIA/IS-99 : Short Message Service, Asynchronous Data Service, and G3 Fax Service
LG-RD2750 is composed of a transceiver, a adapter, a Li-Polymer Battery.
General Introduction
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1. System Introduction
1.1 CDMA Abstract
The cellular system has a channel hand-off function that is used for collecting the information on the
locations and movements of radio mobile telephones from the cell site by automatically controlling
several cell site through the setup of data transmission routes and thus, 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. The analog cellular systems are
classified further into an AMPS system, E-AMPS System, NMT system, ETACS system, and JTACS
system depending on technologies used.
Unlike the Time Division Multiple Access (TDMA) or the 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 SDMA 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 method available 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 characteristics of CDMA.
CHAPTER 1. System Introduction
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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 instead, processed as noise and appears as the self-interference of the system.
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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 fading. 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 obtain 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 more wider frequency
band. The fading related to normal frequency can affect the normal 200~300kHz among signal bands
and accordingly, serious affect 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 and 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 order to increase the call processing capacity
and obtain high-quality 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 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
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characteristics in relation to the mobile station in the cell site. By doing so, all the mobile office
transmit signals in the cells are received by the cell site in the same strength.
Moreover, the backward closed loop power control used by the mobile station to control power with
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 1.25 msec (800 times per
second).
By doing so, the gain tolerance and the different radio propagation loss on the forward/backward link
are complemented.
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 mobile telephone cell
site and 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. In addition, this type of variable voice encoder utilizes adaptive threshold
values when 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
CDMA signals have the function of effectively protecting call confidentiality by spreading and
interleaving call information in broad bandwidth. This makes the unauthorized use of crosstalk, search
receiver, and radio very hard substantially. Also included is the encryption function on various
authentication and calls specified in IS-95 for the double protection of call confidentiality.
2.5 Soft Handoff
During the soft hand, the cell site already in the busy state and the cell site to be engaged in the call
later participate in the call conversion. The call conversion is carried out through the original call
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connection cell site, both cell sites, and then, new cell site. This method can minimize call
disconnection and prevent the user from detecting the hand-off.
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 and accordingly, there is no need to prepare a separate frequency plan. Total
interference generated on mobile station signals 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 signals.
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 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 support, 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.
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3. Structure and Functions of CDMA Mobile Phone
The mobile station of CDMA system is made up of a radio frequency part and logic/control (digital)
part. The mobile station antenna is connected with the transmitter/receiver via a SAW duplexer filter
so that it can carry out the transmit/receive function at the same time.
The transmit frequency is the 25MHz band of 824~849MHz, whereas the receive frequency is the
25MHz band of 869~894MHz. The transmit/receive frequency is separated by 45MHz. The RF signal
from the antenna passes the LNA , bandpass SAW filter having the 1.25MHz band and then, is
directly converted into baseband signal by the frequency synthesizer and frequency down converter.
Baseband output signals that have been filtered from spurious signal are converted into digital signals
via an analog-to-digital converters(Rx ADC) and then, sent out respectively to 5 correlators in each
CDMA de-modulator. Of these, one is called a searcher whereas the remaining 4 are called data
receiver(finger). Rx 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. Then, 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 four 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 handoff during the two cell sites. Moreover,
four data receivers are allocated in order to carry out the de-modulation of these paths. Data output
that has been demodulated change the data string in the combined data row as in the case of original
signals(deinterleaving), and then, are de-modulated by the forward error correction decoder which
uses the Viterbi algorithm.
On the other hand, mobile station user information sent 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 (OQPSK) 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.
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4. Specification
4.1 General Specification
4.1.1 Transmit/Receive Frequency Interval : 45MHz
4.1.2 Number of Channels (Channel Bandwidth) : 20CH (BW : 1.23MHz)
4.1.3 Operating Voltage : DC 3.2~4.2V
4.1.4 Battery Power Consumption : DC 3.7V
SLEEP IDLE MAX POWER
CDMA 1.2 mA 100 ~ 150 mA 580 mA (25dBm)
4.1.5 Operating Temperature : -30°~ +60°
4.1.6 Frequency Stability : ±0.5PPM
4.1.7 Antenna : Fixed PIFA Type (Internal), 50 Ω
4.1.8 Size and Weight
•
Size : 108.5 x 44.5 x 15.6mm (L x W x D)
•
Weight : TBD
4.1.9 Channel Spacing : 1.25MHz
4.1.10 Battery Type, Capacity and Orerating Time
Unit=Hours,Minutes
Standard (1000mAh)
Stand-By Time 160 Hrs (SCI=1)
Talk Time 180 Min (About +92dBm, Half rate)
4.2 Receive Specification
4.2.1 Frequency Range : 869.820 MHz ~ 893.190 MHz
4.2.2 Local Oscillating Frequency Range : 1738.08MHz ~ 1787.94MHz
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4.2.3 Intermediate Frequency : MSM6XXX seires (Zero IF)
4.2.4 Sensitivity : -104dBm ( C/N 12dB or more)
4.2.5 Selectivity : 3dB C/N Degration (With Fch ±1.25KHz : -30dBm)
4.2.6 Spurious Wave Suppression : Maximum of -80dB
4.2.7 CDMA Input Signal Range
•Dynamic area of more than -115~ -12.6 dB : 102.4dB at the 1.23MHz band
4.3 Transmit Specification
4.3.1 Frequency Range : 824.820 MHz ~ 848.190 MHz
4.3.2 Intermediate Frequency : MSM6XXX seires (Zero IF)
4.3.3 Output Power : 0.282W
4.3.4 Interference Rejection
•Single Tone : -30dBm at 900 kHz
•Two Tone : -43dBm at 900 kHz & 1700kHz
4.3.5 CDMA TX Frequency Deviation : ±300Hz or less
4.3.6 CDMA TX Conducted Spurious Emissions
•900kHz : - 42 dBc/30kHz below
•1.98MHz : - 54 dBc/30kHz below
4.3.7 CDMA Minimum TX Power Control : - 50dBm below
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4.4 MS (Mobile Station) Transmitter Frequency
FA NO. CH.NO. CENTER FREQUENCY FA NO. CH.NO. CENTER FREQUENCY
1
2
3
4
5
6
7
8
9
10
1011
29
70
111
152
193
234
275
316
363
824.640 MHz
825.870 MHz
827.100 MHz
828.330 MHz
829.560 MHz
830.790 MHz
832.020 MHz
833.250 MHz
834.480 MHz
835.890 MHz
11
12
13
14
15
16
17
18
19
20
404
445
486
527
568
609
650
697
738
779
837.120 MHz
838.350 MHz
839.580 MHz
840.810 MHz
842.04 MHz
843.270 MHz
844.500 MHz
845.910 MHz
847.140 MHz
848.370 MHz
4.5 MS (Mobile Station) Receiver Frequency
FA NO. CH.NO. CENTER FREQUENCY FA NO. CH.NO. CENTER FREQUENCY
1
2
3
4
5
6
7
8
9
10
1011
29
70
111
152
193
234
275
316
363
869.640 MHz
870.870 MHz
872.100 MHz
873.330 MHz
874.560 MHz
875.790 MHz
877.020 MHz
878.250 MHz
879.480 MHz
880.890 MHz
11
12
13
14
15
16
17
18
19
20
404
445
486
527
568
609
650
697
738
779
882.120 MHz
883.350 MHz
884.580 MHz
885.810 MHz
887.04 MHz
888.270 MHz
889.500 MHz
890.910 MHz
892.140 MHz
893.370 MHz
4.6 Charge time
4.6.1 Standard Battery : Typical 120 ~ 180 Min.
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5. Installation
5.1 Installing a Battery Pack (Soft Pack type)
1) The soft 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) Insert the bottom of battery into the openning on the back of the phone. Then, push the battery
cover up until the latch clicks.
5.2 For Adapter Use
1) Plug the adapter into a wall outlet. The adapter can be operated from either a 110V or a 220V
source.
2) Insert the adapter jack into the phone with the installed battery pack.
Red light indicates battery is being charged. Green light indicates battry is fully charged
5.3 For Mobile Mount
5.3.1 Installation Position
In order to reduce echo sound when using the Hands-Free Kit, make sure that the speaker and
microphone are not facing each other and keep microphone a generous distance from the speaker.
5.3.2 Interface Box
Choose an appropriate flat surface ( somewhere under the dash on the passenger side is preferred )
and mount the IB bracket with the four self-tapping screws provided. Clip the IB into the IB bracket.
5.3.3 Microphone Installation
Install the microphone either by cliiping I onto the sunvisor (driver’s side) or by attaching it to door post
(driver’s side), using a velcno adhesive tape (not included).
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5.3.4 Cable Connections
5.3.4.1 Power and Ignition Cables
Connect the red wire to the car battery positive terminal and the black wire to the car ground. Connect
the green wire to the car ignition sensor terminal. ( In order to operate HFK please make sure to
connect green wire to ignition sensor terminal.) Connect the kit’s power cable connector to the
interface box power receptacle.
5.3.4.2 Antenna Cable Connection
Connect the antenna coupler cable connector from the cradle to the external antenna connector. ( Antenna is not
included.)
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1. Telephone Number and NAM Programming Method : TBD
•Press [#+#+#+#].
Then, the following Menu is appeared.
DEBUG MENU
Service Mode
2Test Screen
1
3Test Call
4Vocoder Set
Sel
5Hybrid Pref
•If you press [1] , display the PHONE MODEL.
DEBUG MENU
Service Mode
2Test Screen
1
3Test Call
4Vocoder Set
OK
5Hybrid Pref
PHONE
MODEL
95
•You can’t edit PHONE MODEL , then press [OK].
DEBUG MENU
Service Mode
2Test Screen
1
3Test Call
4Vocoder Set
OK
5Hybrid Pref
SLOT CYCLE
INDEX
1
•You can edit SLOT CYCLE INDEX (, but not recommended ), then press [OK].
CHAPTER 2. NAM Input Method
(Inputting of telephone numbers included)
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DEBUG MENU
Service Mode
2Test Screen
1
3Test Call
4Vocoder Set
OK
5Hybrid Pref
NAM 1
PHONE NUMBER
0000000000
•Enter the phone number, then press [OK].
DEBUG MENU
Service Mode
2Test Screen
1
3Test Call
4Vocoder Set
Edit OK
5Hybrid Pref
NAM 1
NAME
Empty
•Edit the name of NAM1, the press [OK].
‘NAM 1 NAME’ may display the name of the service provider
DEBUG MENU
Service Mode
2Test Screen
1
3Test Call
4Vocoder Set
Add End
5Hybrid Pref
NAM 1
Standard Program
IS COMPLETE
•Now, the basic programming is completed. To reset the handset, press [Done]. If you want to
program detail informtions for NAM 1, press [Add].
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The detail programming method is same as basic programming. Set up required values and then,
press the [OK] soft key in an effort to move to the next screen.
To return to the last item, press the [Back].
The editable NAM items are followed:
SERVICE SECURITY CODE
NAM 1 MOBILE COUNTRY CODE
NAM 1 MOBILE NETWORK CODE
NAM 1 PRL Enabled ?
NAM 1 CDMA Home System Reg
NAM 1 CDMA Foreign SID Reg
NAM 1 CDMA Foreign NID Reg
NAM 1 CDMA Home SID/NID
NAM 1 Lock out SID/NID
NAM 1 CDMA Primary CH A
NAM 1 CDMA Secondary CH A
NAM 1 CDMA Primary CH B
NAM 1 CDMA Secondary CH B
NAM 1 ACCOLC 0
※Editing this items is not recommended.
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1. RF Transmit/Receive Part
1.1 Overview
The RF transmit/receive part employs the direct conversion architecture (ZIF, Zero Intermediate
Frequency). The transmit/receive frequency is respectively 824.04~848.97MHz and 869.04~893.97
MHz. The block diagram is shown in [Figure 3-1].
RF signals received through the antenna are fed into RFR6122 through the duplexer. And then, they
pass the low noise amplifier (LNA), combined with the signals of local oscillator (VCO) at the
frequency mixer in order to create baseband signal directly.
Baseband signals created are changed into digital signals by the analog / digital converter (ADC, A/D
Converter) and then, auto gain controlled and, sent to the MSM6000 (Mobile Station Modem) of the
digital circuit part. Then, they are demodulated by the modulator / demodulator.
In the case of transmission, MSM6000 modulates, interpolates, and converts the digital signal into an
analog baseband before sending it to the RFT6122.
RFT6122 receives OQPSK-modulated anlaog baseband signals from the MSM6000’s Tx part. The
RFT6122 upconverts the Tx analog baseband into RF.
The RFT6122 connects directly with MSM6000 using an analog baseband interface. In RFT6122, the
baseband quadrature signals are upconverted to the Cellular Tx frequency bands and amplified to
provide signal drive capability to the power amp.
After that, the RF signal is amplified by the Power Amp in order to have enough power for radiation.
Finally, the RF signal is sent out to the cell site via the antenna after going through the duplexer
CHAPTER 3. Circuit Description
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[Figure 3-1] Block Diagram Of RD2750
1.2 Description of Receive Part Circuit
1.2.1 Duplexer (DP100)
The duplexer consists of the receive part bandpass filter (BPF) and the transmit part bandpass filter
(BPF) which have the function of separating transmit/receive signals in the full duplex system using
the transmit/receive common antenna. The transmit part BPF is used to suppress noises and spurious
waves entering the receive band among transmit signals in order to prevent the drop in receive
sensitivity characteristics. The receive part BPF blocks the signals sent out from entering the receive
end in order to improve sensitivity characteristics.
Insertion loss (IL) in the transmit band is 2.8dB (Max), whereas IL in the receive band is 2.1dB (Max).
The receive band attenuation amount of transmit filter is 51dB (Min) and the transmit band attenuation
amount of receive filter is 45dB or more (Min).
1.2.2 LNA (U104)
The RFR6122 has cellular LNA. The characteristics of Low Noise Amplifier (LNA) are low noise
figure, high gain, high intercept point and high reverse isolation. The frequency selectivity
characteristic of mobile phone is mostly determined by LNA.
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