CDMA Glossary N-S
- See Number assignment module.
- Neighbor Set
- The set of pilots associated with the CDMA Channels
that are probable candidates for handoff. Normally the Neighbor Set
consists of the pilots associated with CDMA Channels that cover geographical
areas near the mobile station. See also Active Set, Candidate Set,
and Remaining Set.
- A network is a logical subset of the base stations
in a cellular system, as identified by a SID. The network is identified
by a unique (SID, NID) pair. A network can be as small or as large
as needed, but must be totally contained within a single system.
- Non-Autonomous Registration
- A registration method in which the base station
initiates registration. See also Autonomous Registration.
- Non-Slotted Mode
- An operation mode of the mobile station in which
the mobile station continuously monitors the Paging Channel.
- Nanosecond (10-9 second).
- Null Traffic Channel Data
- One or more frames of 16 '1's followed bu eight
'0's sent at the 1200 bps rate. Null traffic channel data is sent
when no service option is active and no signaling message is being
sent. Null traffic channel data serves to maintain the connectivity
between the mobile station and the base station.
- Number Assignment Module
- A set of MIN-related parameters stored in the mobile
station. The NAM encapsulate the mobile station's network identity.
Multiple NAMs are sometimes provided in a mobile stations so that,
for example, the mobile can have local identities in adjoining service
areas. Use of the NAM is not specified in IS-95, beyond identifying
those semi-permanent station numeric indicators that should be stored
in it [IS-95, Appendix F].
- See Overload class.
- Ordered Registration
- A registration method in which the base station
orders the mobile station to send registration related parameters.
- Overhead Message
- A message sent by the base station on the Paging
Channel to communicate base-station-specific and system-wide information
to mobile stations.
- Overload Class (OLC)
- The means used to control system access by mobile
stations, typically in emergency or other overloaded conditions. Mobile
stations are assigned one (or more) of sixteen overload classes. Access
to the CDMA system can then be controlled on a per class basis by
persistence values transmitted by the base station.
- Overload Control
- A means to restrict reverse analog control channel
accesses by mobile stations. Mobile stations are assigned one (or
more) of sixteen control levels. Access is selectively restricted
by a base station setting one or more OLC bits in the Overload Control
Global Action Message.
- The act of seeking a mobile station in order to
deliver an incoming call.
- Paging Channel
- A forward communication channel used by a base station
to communication to a mobile station when it is not assigned to a
- Parameter-Change Registration
- A registration method in which the mobile station
registers when certain of its stored parameters change.
- Parity Check Bits
- Bits added to a sequence of information bits to
provide error detection, correction, or both.
- A probability measure used by the mobile station
to determine if it should transmit in a given Access Channel Slot.
- Physical Layer
- The part of the communication protocol between the
mobile station and thebase station that is responsible for the transmission
and reception of data. The physical layer in the transmitting station
is presented a frame by the multiplex sublayer and transforms it into
an over-the-air waveform. The physical layer in the receiving station
transforms the waveform back into a frame and presents it to the multiplex
sublayer above it.
- Pilot Channel
- An unmodulated, direct-sequence spread spectrum
signal transmitted continuously by each CDMA base station. The Pilot
Channel allows a mobile station to acquire the timing of the Forward
CDMA Channel, provides a phase reference for coherent demodulation,
and provides a means for signal strength comparisons between base
stations for determining when to handoff.
- Pilot PN Sequence
- A pair of modified maximal length PN sequences with
period 215 used to spread the Forward CDMA Channel and
the Reverse CDMA Channel. Different base stations are identified by
different pilot PN sequence offsets.
- Pilot PN Sequence Offset Index
- The PN offset in units of 64 PN chips of a pilot,
relative to the zero offset pilot PN sequence.
- Pilot Strength
- The ratio of received pilot energy to overall received
energy. See also Ec/I0.
- PN Sequence.
- Pseudonoise sequence. A periodic binary sequence
approximating, in some sense, a Bernoulli (coin tossing) process with
- Point to Point Propagation Model
- A propagation model in which median transmission
loss calculations are based on specific characteristics and terrain
profile of the path along the great circle between the transmitter
- Poisson Blocking Model
- Also called Lost Calls Held or Molina model. A
mathematical model of telephone traffic blocking in which
blocked calls persist for their normal holding time, even
though unserviced. It is similar to the Erlang
C blocking model, with which it is sometimes confused.
The Poisson blocking probability for N resources, callinsity
y Erlangs, is
- Power Control Bit
- A bit sent in every 1.25 ms interval on the Forward
Traffic Channel to signal the mobile station to increase or decrease
its transmit power.
- Power Control Group
- A 1.25 ms interval on the Forward Traffic Channel
and the Reverse Traffic Channel. See also Power Control Bit.
- Power-Down Registration
- An autonomous registration method in which the mobile
station registers on power-down.
- Power-Up Registration
- An autonomous registration method in which the mobile
station registers on power-up.
- Protection of traffic by means of encryption or
other means specifically applied for that purpose.
- Propagation Loss
- The total reduction in radiant power density between
the transmitting antenna and the receiving antenna. Propagation loss
includes both spreading (free space diffraction) loss and attenuation
loss. For non-line of sight situations it also includes diffraction
loss around obstacles. It does not include antenna gain or feeder
loss. Sometimes called isotropic propagation loss.
- Rayleigh Distribution
- The single-parameter probability distribution given
- or the equivalent density
- Rayleigh Fading
- The deep fading process characteristic of narrowband radio
signals in a severe multipath propagation environment. The
probability distribution of complex amplitude tends toward
a bandlimited Gaussian, which has a Rayleigh distribution
of amplitude. Cf. Flat
Selective Fading, Ricean Fading.
- Receive Objective Loudness
- A perceptually weighted transducer gain of telephone receivers
relating electrical excitation from a reference generator
to sound pressure at the earphone. The receive objective
loudness rating is normally specified in dB relative to
one Pascal per millivolt. See IEEE
Standard 269-1992, IEEE
Standard 661-1979, ITU-T
Recommendations P.76 and P.79.
- The process by which a mobile station makes its
presence known to a base station to facilitate call delivery.
- Registration Zone
- A collection of one or more base stations treated
as a unit when determining whether a mobile station should perform
- A process that the mobile station and base station
use to inform each other of call disconnect.
- Reverse CDMA Channel
- The CDMA Channel from the mobile station to the
base station. From the base station's perspective, the Reverse CDMA
Channel is the sum of all mobile station transmissions on a CDMA frequency
- Reverse Traffic Channel
- A Reverse CDMA Channel used to transport user and
signaling traffic from a single mobile station to one or more base
- Rice (or Rician) Distribution
- The probability distribution of the amplitude of
a signal composed of a steady component plus independent IID quadrature
Gaussian processes. It is applicable when a signal arrives at a receiver
by both a line of sight path and by multiple indirect paths. This
two-parameter distribution can be represented as
- where I0 is the modified Bessel function of the first
kind and order zero and a is the amplitude of the steady component.
Note that this reduces to a Rayleigh distribution for a = 0.
- Rician Fading
- The fading process characteristic of radio signals when there is a strong
line-of-sight signal path and multiple non-direct signal paths. The probability
distribution of complex amplitude tends toward a bandlimited Gaussian with
a nonzero mean, which has a Rician distribution of amplitude. Cf. Rayleign
Fading, Flat Fading, Frequency
- A mobile station that is operating in a cellular system other than its home
- See Receive Objective Loudness Rating.
- Normally one angular segment of the coverage area of a cell, served by one
base station. Also used to denote any non-traditional partitioning of the
service area, such one strand of a cable-based delivery system.
- Service Option
- A specific type of user traffic supported by a cellular system. The major
service options are speech codecs, facsimile, and various types of data. Service
options may be negotiated between base and mobile stations during call setup.
- Serving MSC
- The MSC which currently has the mobile station obtaining service at one
of its cell sites within its coverage area.
- Shared Secret Data (SSD)
- A bit pattern stored in the mobile station and known by the base station.
SSD is used to support the authentication procedures and voice privacy. Shared
Secret Data is maintained during power off.
- Signal-to-Noise Ratio (SNR)
- The dimensionless ratio Eb/(N0+I0), or
energy per bit divided by the noise-plus-interference power spectral density.
It is usually stated in dB.
- The information exchanged between the mobile station and the network, or
within the network, for the purposes of service provision (e.g., connection
- Slot Cycle
- A periodic interval at which a mobile station operating in the slotted mode
monitors the Paging Channel.
- Slotted Mode
- An operation mode of the mobile station in which the mobile station monitors
only selected time slots on the Paging Channel when in the Mobile Station
Idle State. The primary purpose of slotted mode is power conservation.
- See Signal to Noise Ratio.
- Soft Handoff
- A handoff occurring while the mobile station is in the Mobile Station Control
on the Traffic Channel State. This handoff is characterized by commencing
communications with a new base station on the same CDMA frequency assignment
before terminating communications with the old base station. Cf. Hard
- See Code Symbol.
- System Identification (SID)
- A number uniquely identifying a cellular system.
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