31.51.118.43 at 20:04, 3 October 2013

2013-10-03T20:04:48Z

← Older revision		Revision as of 22:04, 3 October 2013
Line 1:		Line 1:
	~~Her name~~ is ~~Felicidad Ahmad~~. ~~Interviewing~~ is ~~what she does but quickly she'll~~ be ~~on her own~~. ~~Delaware~~ is ~~extended car warranty the~~ [~~https~~://~~Www~~.~~geico~~.~~com~~/~~getaquote~~/~~auto~~/~~mechanical-breakdown-insurance~~/ ~~location I] love most but I require to transfer for my family members~~. ~~Her [https:~~/~~/Www~~.~~costcoauto~~.~~com~~/~~vpp~~/~~about~~.~~aspx buddies~~] ~~say it~~'s ~~not good~~ for [http://www.~~mystic-balls~~.~~com~~/~~UserProfile~~/~~tabid~~/43/~~userId~~/~~102653~~/~~Default~~.~~aspx auto warranty~~] ~~her but what she enjoys doing~~ is ~~flower arranging and she~~ is trying ~~extended~~ ~~extended auto warranty~~ [http://www.~~carelion~~.~~com~~/~~UserProfile~~/~~tabid~~/61/~~userId~~/~~107768~~/~~Default~~.~~aspx auto warranty~~] to ~~make it a profession.<br><br>my web-site~~ [http://~~pchelpnow~~.~~biz~~/~~ActivityFeed~~/~~MyProfile~~/~~tabid~~/60/~~userId~~/~~48445/Default~~.~~aspx~~ http://~~pchelpnow~~.~~biz~~/~~ActivityFeed~~/~~MyProfile~~/~~tabid~~/60/~~userId~~/~~48445~~/~~Default.aspx~~]		{{Expert-subject\|telecommunications\|date=November 2008}}

			'''CPICH''' stands for ''Common Pilot Channel'' in [[UMTS]] and some other [[CDMA]] communications systems.

			In [[WCDMA]] [[Duplex (telecommunications)#Frequency division duplex\|FDD]] cellular systems, CPICH is a [[downlink]] channel broadcast by [[Node B]]s with constant power and of a known bit sequence. Its power is usually between 5% and 15% of the total Node B transmit power. Commonly, the CPICH power is 10% of the typical total transmit power of 43 [[dBm]].

			The Primary Common Pilot Channel is used by the [[user equipment\|UE]]s to first complete identification of the Primary [[Scrambler (randomizer)\|Scrambling Code]] used for scrambling Primary Common Control Physical Channel (P-[[CCPCH]]) transmissions from the [[Node B]]. Later CPICH channels provide allow phase and power estimations to be made, as well as aiding discovery of other [[Multipath propagation\|radio paths]]. There is one primary CPICH (P-CPICH) for each Cell, which is transmitted using [[spread spectrum\|spreading code]] 0 with a [[Orthogonal variable spreading factor\|spreading factor]] of 256, notationally written as C<sub>ch,256,0</sub>.<ref>[http://www.3gpp.org/ftp/Specs/archive/25_series/25.213/ 25.213], section 5.2.1 "Channelisation codes"</ref> Optionally a Node B may broadcast one or more secondary common pilot channels (S-CPICH), which use arbitrarily chosen 256 codes, written as C<sub>ch,256,n</sub> where <math>0<n<256</math>.

			The CPICH contains 20 bits of data, which are either all zeros, or in the case that Space-Time Transmit Diversity ([[STTD]]) is employed, is a pattern of alternating 1's and 0's for transmissions on the Node B's second antenna.<ref>[http://www.3gpp.org/ftp/Specs/archive/25_series/25.211/ 25.211], section 5.3.3.1 "Common Pilot Channel (CPICH)"</ref> The first antenna of a base station always transmits all zeros for CPICH.

			A UE searching for a [[WCDMA]] Node B will first use the primary and secondary synchronization channels ([[P-SCH]] and [[S-SCH]] respectively) to determine the slot and frame timing of a candidate P-CCPCH, whether STTD is in use, as well as identifying which one of 64 code groups is being used by the cell. Crucially this allows to UE to reduce the set of possible [[Primary Scrambling Codes]] being used for P-CPICH to only 8 from 512 choices. At this point the correct PSC can be determined through the use of a [[matched filter]], configured with the fixed channelisation code C<sub>ch,256,0</sub>, looking for the known CPICH bit sequence, while trying each of the possible 8 PSCs in turn. The results of each run of the matched filter can be compared, the correct PSC being identified by the greatest correlation result.

			Once the scrambling code for a CPICH is known, the channel can be used for measurements of signal quality, usually with [[RSCP]] and E<sub>c</sub>/N<sub>0</sub>. Timing and [[phase (waves)\|phase]] estimations can also be made, providing a reference that helps to improve reliability when decoding other channels from the same Node B.

			Pilot signals are not a requirement of CDMA, however, they do make the UE's receiver simpler and improve the reliability of the system.

			==Further reading==

			*The authoritative definition for CPICH in UMTS is given by [[ITU]] and [[ETSI]] project [[3GPP]] [http://www.3gpp.org/ftp/Specs/archive/25_series/25.211/ 25.211 Physical channels and mapping of transport channels onto physical channels (FDD)]

			* A definition for Ec/Io applicable to CPICH can be found in 3GPP [http://www.3gpp.org/ftp/Specs/archive/25_series/25.133/ 25.133 Requirements for support of radio resource management (FDD)]

			* Some information on the power of CPICH is given in 3GPP [http://www.3gpp.org/ftp/Specs/archive/25_series/25.104/ 25.104 Base Station (BS) radio transmission and reception (FDD)]

			==References==
			<references/>

			[[Category:Universal Mobile Telecommunications System]]

en>Oakley77 at 03:15, 18 June 2012

2012-06-18T03:15:44Z

New page

Her name is Felicidad Ahmad. Interviewing is what she does but quickly she'll be on her own. Delaware is extended car warranty the [https://Www.geico.com/getaquote/auto/mechanical-breakdown-insurance/ location I] love most but I require to transfer for my family members. Her [https://Www.costcoauto.com/vpp/about.aspx buddies] say it's not good for [http://www.mystic-balls.com/UserProfile/tabid/43/userId/102653/Default.aspx auto warranty] her but what she enjoys doing is flower arranging and she is trying extended extended auto warranty [http://www.carelion.com/UserProfile/tabid/61/userId/107768/Default.aspx auto warranty] to make it a profession.<br><br>my web-site [http://pchelpnow.biz/ActivityFeed/MyProfile/tabid/60/userId/48445/Default.aspx http://pchelpnow.biz/ActivityFeed/MyProfile/tabid/60/userId/48445/Default.aspx]

Tach Timer - Revision history

31.51.118.43 at 20:04, 3 October 2013

en>Oakley77 at 03:15, 18 June 2012