CDMA Glossary G-M
- Global Challenge Procedure
- An exchange of information between a mobile station and a base station for
the purpose of authenticating the mobile station identity. The base station
broadcasts a challenge and each mobile station responds with its unique response
when performing a system access. Cf. Unique
Positioning System (GPS)
- A US government satellite system that provides location and time information
to users. See Navstar GPS Space Segment / Navigation User Interfaces ICD-GPS-200
- See Global Positioning System.
- The act of transferring control of a mobile station from one base station
to another. See also Soft Handoff, Hard Handoff.
- Synonym for Handoff.
- Hard Handoff
- A handoff characterized by a temporary disconnection of the Traffic Channel.
Hard handoffs occur when the mobile station is transferred between disjoint
Active Sets, the CDMA frequency assignment changes, the frame offset changes,
or the mobile station is directed from a CDMA Traffic Channel to an analog
voice channel. Cf. Soft Handoff.
- Hash Function
- A mathematical function used by the mobile station to select one out of
N available resources. The hash function ensures statistically uniform use
of the resources.
- Height Above Average Terrain (height AAT)
- See Effective antenna elevation.
- See Home Location Register.
- Home Location Register (HLR)
- The database in a wireless communication network that contains registration
and user profile information for the system subscribers.
- Home System
- The system which is transmitting a system identification (SID) which is
recognized by the mobile station as its Home SID, normally the system in which
service was subscribed (see System Identification).
- Idle Handoff
- The act of transferring reception of the Paging Channel from one base station
to another, when the mobile station is in the Mobile Station Idle State.
- Implicit Registration
- A registration achieved by a successful transmission of an origination or
page response on the Access Channel.
- See International Mobile Subscriber Station Identity.
- The process of reordering code symbols for transmission. Interleaving decorrelates
channel fading between adjacent symbols as they enter the decoder, thereby
improving the effectiveness of the code.
- International Mobile Subscriber Station Identity (IMSI)
- A method of identifying stations in the land mobile service as specifed
in ITU-T Recommendation E.212.
- Kilohertz (103 Hertz).
- Kilosymbols per second (103 symbols per second).
- A conceptual structuring of communication protocols. A layer is defined
in terms of its communnication protocol to a peer layer in another entity,
and the services it provides to the next higher layer in its own entity.
- Layer 1
- See Physical layer.
- Layer 2
- See Link layer.
- Layer 3
- See Application layer.
- See Linear Feedback Shift Register
- Linear FeedbackShift Register (LFSR )
- A logic circuit that produces pseudo-random binary sequences. They are used
to produce the Short Code and Long Code that are used for spreading and for other
purposes in the CDMA system. See the LFSR page for
- Linear Predictive Coding
- A low bit rate coding technique for analog signal sources, usually speech,
that models the production process by a filter whose parameters change slowly
with time. It is a component of CELP coders. See Code Excited Linear Prediction.
- Link Layer
- The link layer of the IS-95 air interface provides for the reliable transmission
and reception of signaling messages, including error detection, partial duplicate
detection and loss. See also Layering, Physical layer, and Application layer.
- Log Normal Distribution
- The distribution of a random variable whose logarithm follows a normal distribution.
A log-normal distribution is characterized by two parameter: its median and
its standard deviation. The logarithm radix is often taken as 10, so that
both the median and the standard deviaion are conveniently measured in decibel
values, m and s. The density function of such a log-normal
variable X is then:
- In the dB measure this is
- where Y = 10 log X.
- Long Code
- A maximal length sequence with period 242-1. A unique phase of
the long code identifies each mobile station. It is used for data scrambling
on the Forward CDMA Channel, spreading on the Reverse CDMA Channel, and other
purposes. See also Maximal length sequence.
- Long Code Mask
- A 42-bit binary number that creates the unique long code phase. See also
public long code, private long code, public long code mask, and private long
- See Linear Predictive Coding.
- Least significant bit.
- Maximal Length Sequence (m-sequence)
- A periodic binary sequence of period 2n-1, n a
positive integer, with no internal periodicities and other curious mathematical
properties [Golomb]. A maximal length
sequence can be generated by either of two equivalent linear feedback shift
register configurations (see LFSR).
- Megachips per second (106 chips per second).
- See Message Error Rate
- In IS-95, a data structure consisting of a length field, message body (or
payload), and CRC for detection of errors.
- Message Error Rate
- Ratio of errored messages to total messages. This is a concept having limited
value because an errored message may be incorrectly fragmented or coalesced
with a neighboring message by the receiver, making the message counts incorrect.
- Megahertz (106 Hertz).
- See Mobile Identification Number.
- Mobile Assisted Handoff (MAHO)
- A means of initiating handoff based on signal quality measurements performed
by the mobile station and reported to the base station.
- Mobile Identification Number (MIN)
- The 34-bit number that is a digital representation of the 10-digit directory
number assigned to a mobile station.
- Mobile Station
- A subscriber station in the Domestic Public Cellular Radio Telecommunications
Service, normally intended to be used while in motion or during halts at unspecified
points. The category my include both true mobile stations, handheld portable
stations, fixed stations, and other devices.
- Mobile Station Class
- A code that defines mobile station maximum transmitter power, slotted operation
capability, and dual-mode CDMA/AMPS capability.
- Mobile Station Identification Number (MSIN)
- A part of the E.212 IMSI identifying the mobile station within its home
network. See ITU-T Recommendation E.212.
- Mobile Switching Center (MSC)
- A configuration of equipment designed to provide interconnection services
among wireless subscriber stations, and between wireless subscriber stations
and the public switched telephone network via one or more base stations under
- Mobile Telephone Switching Office (MTSO)
- An out-of-fashion synonym for Mobile Switching Center.
- Modulation Symbol
- A symbol from a discrete alphabet that identifies a unit of modulation.
In the Forward CDMA Channel, the modulation symbols are binary, each one representing
one interleaved binary symbol from the rate 1/2 convolutional encoder. In
the Reverse CDMA Channel the modulation symbols are six-bit entities comprised
of interleaved bits from the rate 1/3 encoder; the six bits select one of
the 64-Walsh functions for transmission.
- MOS Mean Opinion Score
- The result of a subjective voice quality test, often used to compare speech
codec algorithms, where listeners associate a one to five quality score to
speech samples. The arithmetic mean for a large number of samples is the resulting
MOS number. Care must be used when comparing MOS scores taken in different
tests, as the results for any particular cohort depend very much on the mix
of algorithms under test.
- Millisecond (10-3 second).
- Most significant bit.
- See Mobile Switching Center
- See Mobile Station Identification Number.
- See Mobile Telephone Switching Office.
- Multiplex Option
- One of the alternative designs of the multiplex sublayer. Multiplex options
permit tailoring such characteristics as the data rate set, frame structure,
frame partitioning rules, and rate decision rules for special applications.
- Multiplex Sublayer
- One of the conceptual layers of the system that multiplexes and demultiplexes
primary traffic, secondary traffic, and signaling. The multiplex sublayer
resides between the physical layer and the link layer in the conceptual protocol
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