B3P2 - Mobile and nomadic communications

Question 1

ad hoc mode (WiFi)

Answer 1

where all devices can directly message one other in a WiFi-net;

Question 2

bipolar

Answer 2

where 1s and 0s and repped by +1 and -1 amplitudes;

Question 3

channel bonding

Answer 3

merging 2+ channels for to get widerBandwidth;

Question 4

channel equalisation (refSig)

Answer 4

where referenceSignals are used to check distortion;

Question 5

channelisation (chip) code

Answer 5

where orthogonal chipCodes are used to distinguish simultaneously transmitted dataStreams;

Question 6

chip

Answer 6

bipolarValues of fixedDuration concatenated to rep a 1 or 0;

Question 7

correlation

Answer 7

where a signal is extracted from other signals;

Question 8

cyclic prefix

Answer 8

where the last part of a symbol is copied and pasted to the start of the symbol, thereby protecting against inter-symbol interference;

Question 9

delay spread

Answer 9

the waiting time for all zig-zags of a multipathSignal to arrive;

Question 10

dynamic frequency selection (DFS) [radar]

Answer 10

where the device switches to a different channel if radar is detected in a 5MHz unlicensedBand;

Question 11

fast link adaptation

Answer 11

adapting codeRates and modMethods to mobileComm conditions;

Question 12

frequency division multiplexing (FDD)

Answer 12

where separate frequencyBands are used for uplink and downlink;

Question 13

guard band

Answer 13

where an interval of spectrum is left unused to prevent interference between neighbouring bands;

Question 14

high-speed packet access (HSPA)

Answer 14

uses 15 different 16-chipCodes allocated dynamically to users in WCDMA and 3G;

Question 15

infrastructure mode

Answer 15

where all devices message via the accessPoint in a WiFi-network;

Question 16

maximum transmission rate

Answer 16

the max numUsefulBits that can be transmitted into the channel using the highest codeRate;

Question 17

OFDM symbol period

Answer 17

T_OFDM = T_us + T_cp;

Question 18

orthogonal frequency division multple access (OFDMA)

Answer 18

where users are allocated groups of subchannels each;

Question 19

orthogonal frequency division multiplexing (OFDM)

Answer 19

where closelySpaced subcarriers of signals orthogonally overlap;

Question 20

orhogonal variable speading factor (OVSF)

Answer 20

= chipCodes = channelisationCodes;

Question 21

pilot signal (ref)

Answer 21

reference signals used for distortionCorrection or scheduling;

Question 22

power control (govReg)

Answer 22

baseStationRegs on deviceTransmissionPower in a cell;

Question 23

processing gain (ratio)

Answer 23

spreadBandwidth / unspreadBandwidth;

Question 24

pseudo-random code (pseudo-noise code)

Answer 24

a scrambling-noise code in WCDMA;

Question 25

resource element

Answer 25

a singleSymbol in a singleSubchannel in a resourceBlock;

Question 26

scheduling

Answer 26

the dynamicAllocation of commResources to users;

Question 27

scrambling code

Answer 27

a noise-random-like chipSequence;

Question 28

single-carrier frequency division multiple access (SC-FDMA)

Answer 28

where a symbol is duplicated across all subcarriers in a userResourceAllocation in the uplink in 4G;

Question 29

slot

Answer 29

the fixedDuration of a resource Block = 0.5 ms in 4G;

Question 30

spreading (chip) code

Answer 30

= chipCode = channelisationCode;

Question 31

spreading factor

Answer 31

= numChips in chipCode because chipDuration is fixed;

Question 32

spread-spectrum transmission

Answer 32

where mod-signal is given widerBandwidth to get greater resistance to noise;

Question 33

subcarrier (OFDM)

Answer 33

oneOfThe carrierWaves comprising the OFDM signal;

Question 34

subchannel (OFDM)

Answer 34

isCentredOn and contains subcarrierWave in OFDM;

Question 35

time division du/multiplexing

Answer 35

where a frequencyBand is shared through rapidly alternatingSlots;

Question 36

Transmit Power Control (TPC)

Answer 36

a 5MHzUnlicensedBand protocol where accessPoint sets maxPower for eachDevice;

Question 37

wideband code division multiple access (WCDMA)

Answer 37

where chipCodes enable dataStreams to be transmitted simultaneously over a channel in 3G;

Question 38

wireless local area network (WLAN)

Answer 38

= WiFi net;