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Chapter 2 – RF Planning. Section 4 - Radio Measurements. Objectives. After this module, you will be able to understand: Radio measurement. Radio measurement on SDCCH and TCH. RXLEV measurements. RXQUAL measurements. DIST measurements. Contents. Measurements on RXLEV, RXQUAL, and DIST.
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Chapter 2 – RF Planning Section 4 - Radio Measurements
Objectives After this module, you will be able to understand: • Radio measurement. • Radio measurement on SDCCH and TCH. • RXLEV measurements. • RXQUAL measurements. • DIST measurements.
Contents • Measurements on RXLEV, RXQUAL, and DIST. • Radio Measurement Processing. • Measurement Processing — How Many and When? • Measurement Processing on RXLEV, RXQUAL, and DIST. • HO, Power Control, and Call Clearing Priorities. • Averages When Mobile is High Speed and Turning in the Corners. • RUNHANDOVER = 1
RXLEV, RXQUAL, and DIST measurements Radio Measurements Signal Strength RXQUAL Distance Measured Processing Decision: Handover, Power Control, and Call Clearing
Radio Measurements NCC 3 PLMN PERMITTED MULTI BAND REPORTING NCC 2 NCC 1 900 MHz 1800 MHz
Measurements on Serving and Neighboring cells • MS measures: • RXLEV Downlink • RXQUAL Downlink • RXLEV_NCELL(n) on the 6 nei cells • MS determines • MS_TXPWR_CONF • Serving BTS measures: • RXLEV Uplink • RXQUAL Uplink • Serving BTS evaluates: • MS_BS_distance (TA) • Current BTS TX power • BTS receives • MS_TXPWR_CONF
Measurements on Multiband Cells • MULTIBANDREPORTING = Three strongest cells out band out band • B • - 90 dBm • C - 93 dBm • D - 92 dBm • A - 88 dBm MS in- in band • F - 83 dBm • G - 89 dBm • E - 96 dBm in band • I - 97 dBm • H - 91 dBm Six neighboring cells the MS will report to its serving cell
235 ms Measurements on SDCCH/8 Down link (SDCCH/8) - D0 D1 D2 D3 D4 D5 D6 D7 A0 A1 A2 A3 - - D0 D1 D2 D3 D4 D5 D6 D7 A4 A5 A6 A7 - - - D0 to D7 is data blocks A0 to A7 is SACCH block Uplink SDCCH (SDCCH/8) - - - - A5 A6 A7 D0 D1 D2 D3 D4 D5 D6 D7 A0 - - - - A1 A2 A3 D0 D1 D2 D3 D4 D5 D6 D7 A4 One SACCH block contains 4 SACCH TS. Time taken to send a SACCH block is 2 x 235 = 470 ms.
TCH .................. TCH TCH ................... TCH 120 ms Measurements on TCH One SACCH block contains 4 SACCH TS. Time taken to send a SACCH block is 4 x 120 = 480 ms. 12 TCH 12 TCH Idle SACCH
RXLEV in dBm is given by -110 + RXLEV (-110 and –47dBm) RXLEV is coded onto 6 bits and its ranges from 0 to 63 RXLEV RXLEV Measurements
RXQUAL Measurements RXQUAL is coded onto 3 bits and its ranges from 0 to 7
MS-BS DIST Measurements TDMA Frame Without TA TS2 TS1 TS expected by the BTS TS1 TS2 Anticipation of the MS transmission 3 TS TS1 TS2 3 TS - d t TS1 TS2 TA(d) = 2 x t MS advances its transmission time of d
MS-BS DIST (TA) Measurements TA is coded onto 6 bits and its ranges from 0 to 63 In dedicated mode System is continuously evaluates MS_BS Distance( HO and Call Clearing) MS_BS DISTANCE (m) = T * V / (2 * B) * TA T = Duration of one TS 577 µs B = Bit period for 1TS = 156.25 V = Velocity of light
Measurements on Neighboring Cell idle TC1 TC24 TC25 MS in serving Cell TS0 TS0 TS0 TS0 TS0 Monitoring window Measurements on neighboring BCCH frequency Neighbor BTS
F1 F1 D(frequency reuse distance) Discontinuous Transmission Discontinuous transmission reduces the interference(ACI and CCI) Hand portable battery duration increases
Discontinuous Transmission MS may use DTX MS shall use DTX MS shall not use DTX DTX DL enabled DTX DL disabled DTXMODE CELLDTXDOWNLINK BTS control of the discontinuous transmission in a cell. MS control of the discontinuous transmission mechanism in a cell.
DTX_NOT USED DTX_ USED DOWNLINK RXLEV_FULL_SERVING_CELL RXQUAL_FULL_SERVING_CELL RXLEV_SUB_SERVING_CELL RXQUAL_SUB_SERVING_CELL UPLINK RXLEV_FULL_UP RXQUAL_FULL_UP RXLEV_SUB_UP RXQUAL_SUB_UP Discontinuous Transmission RXLEVUL_SUB RXLEVUL_FULL RXQUAL_SUB RXQUAL_FULL DTX_USED or DTX_NOT USED RXLEVDL_SUB RXLEVDL_FULL RXQUALDL_SUB RXQUALDL_FULL DTX_USED or DTX_NOT USED
Radio Measurement Processing • Measurement processing • Averages on RXLEV, RXQUAL, RXLEV_NCELL and DIST. • Arithmetic and weighted averages. • The averaged values are calculated periodically.
Data Requirement for Different Processes RXLEV BTS Tx power and MS power RXQUAL Dist Power budget Power Control Handover Call Clearing RUNPWRCONTROL RUNHANDOVER RUNCALLCLEAR
Measurement Processing — How Many and When? Types of average Arithmetic Super average Weighted average Periodically calculated Calculated at every RUN_YY XX_HREQAVE is used XX_HREQT is used Periodically calculated XX_HREQAVE*XX_HREQT
M1 + M2 + M3 + M4 4 RXLEV_NCELL(n) = Mean E1 = Measurement Processing on Neighboring Cell(RXLEV_NCELL(n)) SACCH BLOCKS M4 M1 M2 M3 TIME 480 ms Mean E1 RXNCELLHREQAVE = Number of measurements are taken to calculate the mean for neighboring cells. RXNCELLHREQAVE = 4
W3 W2 Weighted Mean M1*W3 + M2*W2 + M3*W1 W3+W2+W1 Weighted average(WA) = Measurement Processing on Distance SACCH BLOCKS M1 M2 M3 TIME W1 480 ms Where weights W1 = 45 W2 = 30 W3 = 25 DISTHREQT = 3 DISTWTSLIST = W1 W2 W3 WA DISTHREQT = Number of measurements are taken to calculate the weighted average for distance It is calculated everyRUNCALLCLEARand RUNHANDOVER
E1*W3 + E2*W2 + E3*W1 W3+W2+W1 Final data (average) = Measurement Processing for RXLEV and RXQUAL RXLEVHREQAVE = 4 RXQUALHREQAVE = 4 SACCH BLOCKS TIME 480 ms MEAN MEAN MEAN RXLEVHREQT = 3 RXQUALHREQT = 3 W3 W2 W1 E1 E2 E3 WEIGHTED MEAN Sum of the weights Is 100 RXLEVWTSLIST = (W1 W2 W3) RXQUALWTSLIST= (W1 W2 W3)
Call Clearing, Power Control, and Handover Priorities Call Clearing During call clearing no power control and handover is required Power Control Handover and power control are independent Handover First power control and then handover
HREQUAVE is Small For quicker handover Shorter averages Measurements on current and neighboring cells Averaging on small measurements Useful for MS turning at a street corner and entering a tunnel, etc For early handover HREQUAVE is small
Shorter Averages on the Serving Cell RXLEVHREQAVE= 2, RXLEVHREQAVEBEG= 2 RUNHANDOVER = 1,RXLEVHREQT = 2, shorter average Beg arithmetic average Weighted average Product of HREQAVE and HREQT is four
Shorter Averages on the Neighboring Cells RUNHANDOVER= 1 Beg Weighted average RXLEVHREQAVEBEG= 2 RXLEVHREQT= 1 shorter average RXLEVHREQAVE= 4 Beg Arithmetic Neighboring Cell A RXNCELLHREQAVEBEG= 2 Beg Arithmetic Neighboring Cell B RXNCELLHREQAVE=4 Product of HREQAVE and HREQT is four