`
`CR page 1
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`3GPP RAN1/RAN2 joint meeting on LTE R2-060988
`Athens, Greece, 27–31 March, 2006
`
`
`Agenda Item: 3.5
`Source:
`
`CATT
`Title:
`
`
`PCH mapping and Paging control
`Document for: Discussion and decision
`
`Introduction
`This document discusses the PCH mapping and paging control in the physical layer. It is proposed that the PCH is
`mapped on the downlink physical shared channel, and the paging indicating channel is combined with downlink
`shared control channel. Two methods are presented for indicating the paging indicator in downlink shared control
`channel.
`
`
`Discussion
`1. The Mapping of PCH
`
`In the TR25.813, the Paging channel is characterised by:
`- support of UE power saving (DRX cycle is indicated by the network to the UE);
`
`-
`
`requirement to be broadcast in the entire coverage area of the cell;
`
`- mapped to physical resources which can be used dynamically also for traffic/other control channels.
`
`So, PCH can be mapped on the downlink physical shared channel (named as DPSCH for short). While no paging,
`the DPSCH doesn’t carry any content of PCH to save the radio resource. Additionally, the data amount of PCH is
`much usually, UE will spend more time and power for reading it. For supporting UE power saving, a paging
`indicating channel in physical layer should be configured to indicate whether having PCH. UEs will listen to the
`paging indicating signal in DRX mode. As PCH is mapped on DPSCH and the scheduling information of DPSCH
`is carried on the downlink shared control channel (named as DSCCH for short), we can combined the paging
`indicating channel into DSCCH. The occasion of paging indicator appears on the DSCCHs with DTX period.
`Which DSCCH carry the paging indicator and the DTX period is broadcasted on the BCH.
`The location of resource using by PCH is fixed with paging indicator, which can be broadcasted in BCH of
`determined by specification.
`An example is shown in the Figure 1.
`
`PCH
`
`Transport channel
`
`DSCCH(Paging indicator)
`
`DPSCH
`
`Physical channel
`
`DPSCH
`
`UE2
`Data
`
`UE1
`Data
`
`UE2
`Data
`
`UE1
`Data
`
`UE2
`Data
`
`UE1
`Data
`
`UE2
`Data
`
`UE1
`Data
`
`UE2
`Data
`
`UE1
`Data
`
`
`PCH
`Data
`
`UE1
`Data
`
`R2-060988
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`1
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`Ericsson v. IV II LLC
`Ex. 1005 / Page 1 of 5
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`CR page 2
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`DSCCH
`SFN
`
`UE1
`1
`
`UE2
`2
`
`UE1
`3
`
`UE2
`4
`
`UE1
`5
`
`UE2
`6
`
`UE1
`7
`
`UE2
`8
`
`UE1
`9
`
`PI
`10
`
`UE1
`11
`
`UE2
`12
`
`Paging period (no paging)
`
`Paging period
`
`
`Figure 1: PCH mapping
`
`In Figure 1, SFN #5, 10 in DSCCH are the paging indicator occasion. But in the SFN #5, there is no paging
`information, so the scheduling information to UE1 is carried on DSCCH, in subsequent SFN, i.e. SFN #6, UE1
`transmits/receives data. In the SFN #10, paging indicator is presented on DSCCH, and the PCH information
`appears in SFN #11.
`2. The DSCCH Frame
`Two solutions are depicted below for distinguishing the paging indicator and scheduling information on DSCCH.
`1). Introducing a PI-ID. This PI-ID equals to C-RNTI in size, and isn’t assigned to any UE for ever. When the
`special PI-ID has been detected, the content carried on DSCCH is a paging indicator. The structure of DSCCH
`frame is as following:
`
`C-RNTI/PI-ID
`
`……
`
`
`2). Adopting a paging tag field. This paging tag field is used in DSCCH frames, which indicates whether the
`content carried on DSCCH is a paging indicator or normal scheduling information. For example, when the paging
`tag is set to 0, it shows the content is normal scheduling information. By contraries, when the paging tag is set to 1,
`it shows the content is paging indicators. The structure of DSCCH frame is as following:
`Paging tag
`……
`
`
`With one of the solutions above, there is no any paging indicator in the DSCCH even the occasion of paging
`indicating comes while no PCH information. The corresponding resource can be used for scheduling and
`transmission. If the paging indictor is presented on DSCCH, the corresponding resource of DPSCH will be
`utilized to transfer the data of PCH. Other static information, e.g. demodulation and decode parameter, may be
`broadcasted on the BCH.
`
`
`
`3. Paging control procedure
`The paging control procedure is depicted as following in detail according to each structure of DSCCH frame:
`1). Using a PI-ID
`If there is no paging, the eNodeB transfers scheduling information on the DSCCHs with a C-RNTI allocated to a
`UE, then transfers data on the related DPSCH. If there is paging message coming from aGW, the eNodeB sends
`paging indicator and resources indicating of DPSCH on DSCCH when the paging occasion comes, and set the
`PI-ID in the DSCCH frame instead of C-RNTI at the same time.
`UEs in LTE-IDLE monitor the DSCCHs that may carry paging indicators with DRX period. UEs will inspect the
`UE-ID information firstly once receiving the DSCCHs frame. If the UE-ID is not the PI-ID, it means there is no
`paging information. These UEs will return to dormant state, and monitor paging indicator in the next DRX
`occasion.
`When the UE-ID is PI-ID, UEs will read the paging indicator belonging to themselves. The UE will return to
`dormant state and monitor DSCCH in next DRX occasion, if no exact paging information associated with it.
`Otherwise, the UE reads scheduling information; and receives the paging data carried on DPSCH, and then deals
`with paging message. The procedure depicted above is shown in Figure 2.
`UEs in LTE_ACTIVE state decide next execution based on the UE-ID taken on DSCCH like current system.
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`R2-060988
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`Ex. 1005 / Page 2 of 5
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`CR page 3
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`UEs in IDLE monitor DSCCH in
`
` Is PI=ID?
`
`Yes
`
`Read paging indicator in DSCCH
`
`No
`
`Go to dormant
`state
`
`Is my Paging?
`
`No
`
`Yes
`Read resource indicating of DPSCH in DSCCH
`
`Read PCH data in DPSCH and deal with it
`
`
`
`Figure 2: The control procedure of Idle UE
`
`
`2). Using paging tag.
`If there is no paging, the eNodeB transfers scheduling information in which paging tag = 0 on the DSCCHs with
`the scheduled UE’s C-RNTI, and traffic data on the DPSCH. If there is paging message coming from aGW, the
`eNodeB will transmit the paging indicators and resources indicating on DSCCH in which the paging tag=1 at the
`paging occasion, then transfer the paging information on DPSCH subsequently.
`UEs in LTE_IDLE state receive the cell broadcast and get the information about how to demodulation the paging
`data. Then UEs will monitor the DSCCHs that may carry paging indicator with DRX period. After receiving the
`DSCCH frames, UEs will judge the paging tag firstly.
`If the paging tag equals to 0, there is no paging information. These UEs return dormant state, and monitor paging
`indicator in the next paging occasion.
`If the paging tag equals to 1, there is paging information. The UE will read the paging indicator belong to itself.
`These UEs will return to dormant state if there is no paging information associated with them, and monitor paging
`indicator in the next paging occasion. Otherwise, UEs will read scheduling information, and receive the paging
`data on DSPCH, then deal with the paging message.
`The control procedure of UE in LTE-IDLE is show in figure 3.
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`R2-060988
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`Ex. 1005 / Page 3 of 5
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`CR page 4
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`UE in LTE-IDLE read DSCCH in DRX
`
`No
`
`Go to dormant
`state
`
`Paging tag = 1?
`
`Yes
`
`UE in IDLE reads paging indicator in DSCCH
`
`Is my Paging?
`
`No
`
`Yes
`UE in IDLE reads resource indicator of DPSCH in
`
`Read PCH data in DPSCH and deal with it
`
`
`
`figure 3. The control procedure of Idle UE using paging tag
`UEs in LTE_ACTIVE decide next execution according to paging tag. If the paging tag equals 0, the active UEs
`deal with DSCCHs as normal mode. If the paging tag equals 1, the active UEs don't receive information on
`DPSCH and monitor other DSCCHs continuely. The control procedure of Active UE using paging tag is show in
`figure 4.
`
`Active UE read DSCCH
`
`Paging tag = 0?
`
`Yes
`
`No
`
`Don’t deal with DPSCH
`
`Deal with DPSCH as normal mode
`
`contiue to monitor DSCCHs
`
`figure 3. The control procedure of Active UE using paging tag
`
`
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`
`
`Conclusion
`The contribution discusses the paging mapping and paging control procedure. The PCH is mapped on the DPSCH,
`and the paging indicating channel is combined with DSCCH. The radio resource is saved if the schemes were
`adopted and the scheduling of radio resouce is very flexible. For these two solutions above that used for
`distinguishing paging indicator and scheduling information, we prefer to the first one, i.e. using a special PI-ID.
`
`References
`[1]
`TR25.813 “Radio interface protocol aspects”
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`R2-060988
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`4
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`Ex. 1005 / Page 4 of 5
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`CR page 5
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`[2]
`
`TR25.814 “Physical Layer Aspects for Evolved UTRA”
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`R2-060988
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`5
`
`Ex. 1005 / Page 5 of 5
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