CN101335550B - Configuring and transmitting method of uplink control channel configuration parameter - Google Patents

Abstract

The invention provides a configuring and transmitting method of the configuring parameters of uplink control channels, which can save signaling expenses. The transmitting method comprises the following steps: a uniform cyclic shift parameter table is stored in advance in a base station and in user equipment (UE), the cyclic shift parameter table comprises a cyclic shift quantity and deviation combinations of the cyclic shift quantity and the index value corresponding to each combination. When needing to broadcast to the UE the cyclic shift quantity and the deviations of the cyclic shift of a cell where the UE is located, the base station selects a set of cyclic shift quantity and cyclic shift deviation from the cyclic shift parameter table, extracts the index value corresponding to the combination and broadcasts the index value to the UE; after the UE acquires the index value, a corresponding set of cyclic shift quantity and cyclic shift deviation is read from the cyclic shift parameter table stored in the UE according to the index value.

Description

A kind of configuration of uplink control channel configuration parameter and sending method

Technical field

The present invention relates to the communications field, be specifically related to a kind of configuration and sending method of uplink control channel configuration parameter.

Background technology

The frame structure (being called again the Equations of The Second Kind frame structure, i.e. frame structure type 2) of LTE system TDD (Time Division Duplex, time division duplex) pattern as shown in Figure 1.In this frame structure, the radio frames of a 10ms (307200Ts, 1ms=30720Ts) is divided into two fields, each half frame length 5ms (153600Ts).The subframe that it is 1ms that each field comprises 5 length.The effect of each subframe is as shown in table 1, and wherein the D representative is used for the descending sub frame of transmission of downlink signal.The U representative is used for the sub-frame of uplink of transmission upward signal.In addition, upstream or downstream subframe is divided into again the time slot of 2 0.5ms.S represents special subframe; comprise three special time slots, i.e. DwPTS (Downlink Pilot Time Slot, descending pilot frequency time slot), GP (Guard Period; protect the interval) and UpPTS (Uplink Pilot TimeSlot, uplink pilot time slot).In real system, the uplink and downlink configuration index can be notified to mobile phone by broadcast.

The configuration of table 1 uplink and downlink

The frame structure (being called again first kind frame structure, i.e. frame structure type 1) of the FDD of LTE system (Frequency Division Duplex, Frequency Division Duplexing (FDD)) pattern as shown in Figure 2.The radio frames of a 10ms is divided into the time slot of 20 0.5ms, and adjacent 2 time slots form the subframe that length is 1ms, and namely subframe i is comprised of time slot 2i and 2i+1, i=0 wherein, and 1 ..., 9.Under fdd mode, 10 subframes all are used for the transmission of upstream or downstream signal, distinguish by different frequency bands between uplink and downlink.

Resource in the LTE system is divided and is equipped with RB (Resource Block, Resource Block) be unit, a RB accounts for 12 RE (Resource Element on frequency domain, resource element), account for a time slot on time domain, i.e. 7 (general cyclic prefix CP, Normal cyclic prefix) or 6 (expansion CP, Extendedcyclic prefix) SC-OFDM (single carrier orthogonal frequency division multiplexing) symbols.If RB corresponding to definition up-link bandwidth adds up to N _RB ^UL, the index of RB is 0,1 ..., N _RB ^UL-1.

PUCCH (Physical uplink control channel, Physical Uplink Control Channel) channel format can be divided into two large classes, and totally 6 kinds: the first kind comprises 3 kinds of forms, i.e. format 1,1a, 1b, Equations of The Second Kind comprises 3 kinds of forms, i.e. format 2,2a, 2b.First kind PUCCH is used for transmission SR (schedulingrequest, dispatch request) and ACK (Acknowledgement, reply)/NACK (NegativeAcknowledgement, negative response) signaling, wherein, format 1 is used for transmission SR, format 1a and is used for the ACK/NACK of transmission pair streams of code words for ACK/NACK, the format 1b of transmission single codeword stream.Equations of The Second Kind PUCCH is mainly used in transmitting CQI (Channel Quality Indicator, CQI), wherein 2 of format transmit CQI, format 2a is used for transmitting simultaneously the ACK/NACK of CQI and single codeword stream, and format 2b is used for transmitting simultaneously the ACK/NACK of CQI and two streams of code words.First kind PUCCH quantity (CCE, Control Channel Element) of shared RB number and down control channel unit in a time slot is relevant, is dynamic change; Equations of The Second Kind PUCCH shared RB number in a time slot notifies to all UE in the residential quarter by broadcast channel, is semi-static configuration.In addition, for fear of the waste of code resource, the LTE system has also defined mixing RB, the multiplexing first kind and Equations of The Second Kind PUCCH channel.Whether exist mixing RB to configure in system, and in a time slot, have at most one to mix RB.In common sub-frame of uplink, the channel architecture of PUCCH as shown in Figure 3, a PUCCH resource units accounts for two time slots, accounts for a RB on a time slot, and on two time slots, the frequency domain position of RB is symmetrical.

First kind PUCCH channel is the different cyclic shift α (n by different orthogonal sequence (Orthogonalsequences) and Zadoff-Chu sequence in a resource units _s) produce different PUCCH channel (or being called the PUCCH resource), distribute to different users.Cyclic shift is by following calculation of parameter:

Cyclic shift value n by the residential quarter _cs ^Cell(n _s, l), n _cs ^Cell(n _s, l) with timeslot number n _sReach the variation of notation index l and change;

Cyclic shift amount Δ _Shift ^PUCCH(cyclic shift quantities, or be called step length of cyclic shift);

Cyclic shift amount skew δ _Offset ^PUCCH

Orthogonal sequence index n _oc(n _s);

The parameter N such as first kind PUCCH channel resource number ';

The resource index n ' (n of first kind PUCCH channel _s);

Resource block size on frequency domain (being the quantity of subcarrier on frequency domain) N _sc ^RB

The span of cyclic shift amount is ${\mathrm{\Δ}}_{\mathrm{shift}}^{\mathrm{PUCCH}}\∈\left\{\mathrm{1,2,3}\right\}$ , the span of cyclic shift is ${\mathrm{\δ}}_{\mathrm{offset}}^{\mathrm{PUCCH}}\∈\{\mathrm{0,1},...,{\mathrm{\Δ}}_{\mathrm{shift}}^{\mathrm{PUCCH}}-1\}$ 。Cyclic shift amount Δ in the residential quarter _Shift ^PUCCHAnd cyclic shift δ _Offset ^PUCCHBy the base station by all UE (User Equipment, subscriber equipment) in the broadcast channel notifying cell.Cyclic shift amount Δ _Shift ^PUCCHThree kinds of values are arranged, need 2 bits to notify.Cyclic shift δ _Offset ^PUCCHThe bit number that needs is decided by its maximum occurrences, when ${\mathrm{\Δ}}_{\mathrm{shift}}^{\mathrm{PUCCH}}=2$ The time, δ _Offset ^PUCCHNeed 2 bits to represent, notify like this Δ _Shift ^PUCCHAnd δ _Offset ^PUCCHJust need the signaling consumption of 4 bits.Although this method can represent Δ _Shift ^PUCCHAnd δ _Offset ^PUCCHAll values, but signaling consumption is larger.Therefore need a kind of more rational signaling format of design, not only want to notify all values of cyclic shift amount and cyclic shift, also want to save to greatest extent the expense of signaling.

Summary of the invention

Problem to be solved by this invention is to provide a kind of configuration and sending method of uplink control channel configuration parameter, can the saving signaling expense.

In order to solve the problems of the technologies described above, the invention provides a kind of collocation method of uplink control channel configuration parameter, comprise: the corresponding relation of setting up the skew of cyclic shift amount and cyclic shift amount, and be each group cyclic shift amount and index value of cyclic shift amount skew distribution, set up the corresponding relation of index value and cyclic shift amount and cyclic shift amount offset combinations.

Further, described method comprises:

(a) set up the corresponding relation of cyclic shift amount and the skew of cyclic shift amount according to the span of cyclic shift amount and the skew of cyclic shift amount;

(b) be each group cyclic shift amount and index value of cyclic shift amount skew distribution, described index value is nonnegative integer, and the maximum of index value is less than 8;

(c) set up the corresponding relation of index value and cyclic shift amount and cyclic shift amount offset combinations.

Further, when the span of cyclic shift amount is 1 to 3, the cyclic shift amount be 1 with the corresponding index value of combination of cyclic shift amount skew 0; The cyclic shift amount be 2 with the corresponding index value of combination of cyclic shift amount skew 0; The cyclic shift amount be 2 with the corresponding index value of combination of cyclic shift amount skew 1; The cyclic shift amount be 3 with the corresponding index value of combination of cyclic shift amount skew 0; The cyclic shift amount be 3 with the corresponding index value of combination of cyclic shift amount skew 1; The cyclic shift amount be 3 with the corresponding index value of combination of cyclic shift amount skew 2.

Further, in described step (b), during the allocation index value, get 8 with interior, do not comprise that any 6 not identical values of 8 are as index value.

Further, each cyclic shift amount and the corresponding index value of cyclic shift amount offset combinations are following any one: 0,1,2,3,4,5; 5,4,3,2,1,0; 1,2,3,4,5,6; 6,5,4,3,2,1; 2,3,4,5,6,7; 7,6,5,4,3,2.

In order to solve the problems of the technologies described above, the present invention also provides a kind of sending method of uplink control channel configuration parameter, comprising:

Preserve in advance unified cyclic shift parameter list on base station and user equipment (UE), described cyclic shift parameter list comprises: the combination of cyclic shift amount and the skew of cyclic shift amount, and the corresponding index value of each combination;

When cyclic shift amount in this residential quarter, UE place and cyclic shift will be broadcasted to described UE in the base station, one group of cyclic shift amount and cyclic shift are chosen in described base station from described cyclic shift parameter list, extract index value corresponding to this combination, described index value is broadcast to described UE;

After described UE obtains described index value, read corresponding one group of cyclic shift amount and cyclic shift in the cyclic shift parameter list of preserving from it according to this index value.

Adopt the method for the invention, can also save to greatest extent signaling consumption in all values of the cyclic shift amount that represents ascending control channel and cyclic shift.The inventive method only needs the signaling of 3 bits can represent all values of cyclic shift amount and cyclic shift, compares with 4 bit signallings, has saved 25% signaling consumption.

Description of drawings

Fig. 1 is the frame assumption diagram of LTE system TDD mode;

Fig. 2 is the frame assumption diagram of LTE system fdd mode;

Fig. 3 is the channel architecture schematic diagram of PUCCH;

Fig. 4 is the flow chart of configuration cycles shift amount and the skew of cyclic shift amount.

Embodiment

As shown in Figure 4, when the cyclic shift amount of collocating uplink control channel and the skew of cyclic shift amount, the corresponding relation (step 410) that model cyclic shift amount and cyclic shift amount are offset; And be that each group cyclic shift amount and cyclic shift amount are offset a distribution index value (step 420); Set up the corresponding relation (step 430) of index value and cyclic shift amount and cyclic shift amount offset combinations.

Need consider the span of cyclic shift amount and the skew of cyclic shift amount when setting up the corresponding relation of cyclic shift amount and cyclic shift amount skew, the span that is offset due to the cyclic shift amount is ${\mathrm{\δ}}_{\mathrm{offset}}^{\mathrm{PUCCH}}\∈\{\mathrm{0,1},...,{\mathrm{\Δ}}_{\mathrm{shift}}^{\mathrm{PUCCH}}-1\}$ , therefore, when the span of cyclic shift amount is ${\mathrm{\Δ}}_{\mathrm{shift}}^{\mathrm{PUCCH}}\∈\left\{\mathrm{1,2,3}\right\}$ The time, the corresponding relation of cyclic shift amount and cyclic shift amount skew can only be: the cyclic shift amount is 1 to be offset 0 corresponding with the cyclic shift amount; The cyclic shift amount is 2 corresponding with cyclic shift amount skew 0; The cyclic shift amount is 2 corresponding with cyclic shift amount skew 1; The cyclic shift amount is 3 corresponding with cyclic shift amount skew 0; The cyclic shift amount is 3 corresponding with cyclic shift amount skew 1; The cyclic shift amount is 3 corresponding with cyclic shift amount skew 2.In other embodiments, if the span of cyclic shift amount changes, so rebulid both corresponding relations according to both span.

The value of each index variables is nonnegative integer, and the maximum that need to guarantee index value takies and is no more than 3 bits.That is to say, the maximum of index value should be less than 8.

Implement one

At first, set up the combination of cyclic shift amount and cyclic shift amount skew, and be index variables of each combination distribution:

With the cyclic shift amount be 1 with the combination manipulative indexing variable a of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable b of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable c of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable d of cyclic shift amount skew 0;

With the cyclic shift amount be 3 with the combination manipulative indexing variable e of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable f of cyclic shift amount skew 2;

Then, determine the value of each index variables: value is nonnegative integer, and the maximum that guarantees sequence number is less than thresholding 8, in the present embodiment, index variables a, b, c, d, e, the value of f is respectively 0,1, and 2,3,4,5;

At last, set up index value with the corresponding relation of the combination of cyclic shift amount and cyclic shift amount skew is as shown in table 2.

Table 2

index	Δ shift PUCCH	δ offset PUCCH
			0	1	0
1	2	0
			2	2	1
3	3	0
			4	3	1
5	3	2

Implement two

At first, set up the combination of cyclic shift amount and cyclic shift amount skew, and be index variables of each combination distribution:

With the cyclic shift amount be 1 with the combination manipulative indexing variable a of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable b of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable c of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable d of cyclic shift amount skew 0;

With the cyclic shift amount be 3 with the combination manipulative indexing variable e of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable f of cyclic shift amount skew 2;

Then, determine the value of each index variables: value is nonnegative integer, and the maximum that guarantees sequence number is less than thresholding 8, in the present embodiment, index variables a, b, c, d, e, the value of f is respectively 1,2, and 3,4,5,6;

At last, set up index value with the corresponding relation of the combination of cyclic shift amount and cyclic shift amount skew is as shown in table 3.

Table 3

index	Δ shift PUCCH	δ offset PUCCH
			1	1	0
2	2	0
			3	2	1
4	3	0
			5	3	1
6	3	2

Implement three

At first, set up the combination of cyclic shift amount and cyclic shift amount skew, and be index variables of each combination distribution:

With the cyclic shift amount be 1 with the combination manipulative indexing variable a of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable b of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable c of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable d of cyclic shift amount skew 0;

With the cyclic shift amount be 3 with the combination manipulative indexing variable e of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable f of cyclic shift amount skew 2;

Then, determine the value of each index variables: value is nonnegative integer, and the maximum that guarantees sequence number is less than thresholding 8, in the present embodiment, index variables a, b, c, d, e, the value of f is respectively 2,3, and 4,5,6,7;

At last, set up index value with the corresponding relation of the combination of cyclic shift amount and cyclic shift amount skew is as shown in table 4.

Table 4

index	Δ shift PUCCH	δ offset PUCCH
			2	1	0
3	2	0
			4	2	1
5	3	0
			6	3	1
7	3	2

Implement four

At first, set up the combination of cyclic shift amount and cyclic shift amount skew, and be index variables of each combination distribution:

With the cyclic shift amount be 1 with the combination manipulative indexing variable a of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable b of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable c of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable d of cyclic shift amount skew 0;

With the cyclic shift amount be 3 with the combination manipulative indexing variable e of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable f of cyclic shift amount skew 2;

Then, determine the value of each index variables: value is nonnegative integer, and the maximum that guarantees sequence number is less than thresholding 8, in the present embodiment, index variables a, b, c, d, e, the value of f is respectively 5,4, and 3,2,1,0;

At last, set up index value with the corresponding relation of the combination of cyclic shift amount and cyclic shift amount skew is as shown in table 5.

Table 5

index	Δ shift PUCCH	δ offset PUCCH
			5	1	0
4	2	0
			3	2	1
2	3	0
			1	3	1

0

3

2

Implement five

At first, set up the combination of cyclic shift amount and cyclic shift amount skew, and be index variables of each combination distribution:

With the cyclic shift amount be 1 with the combination manipulative indexing variable a of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable b of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable c of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable d of cyclic shift amount skew 0;

With the cyclic shift amount be 3 with the combination manipulative indexing variable e of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable f of cyclic shift amount skew 2;

Then, determine the value of each index variables: value is nonnegative integer, and the maximum that guarantees sequence number is less than thresholding 8, in the present embodiment, index variables a, b, c, d, e, the value of f is respectively 6,5, and 4,3,2,1;

At last, set up index value with the corresponding relation of the combination of cyclic shift amount and cyclic shift amount skew is as shown in table 6.

Table 6

index	Δ shift PUCCH	δ offset PUCCH
			6	1	0
5	2	0
			4	2	1
3	3	0
			2	3	1
1	3	2

Implement six

At first, set up the combination of cyclic shift amount and cyclic shift amount skew, and be index variables of each combination distribution:

With the cyclic shift amount be 1 with the combination manipulative indexing variable a of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable b of cyclic shift amount skew 0;

With the cyclic shift amount be 2 with the combination manipulative indexing variable c of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable d of cyclic shift amount skew 0;

With the cyclic shift amount be 3 with the combination manipulative indexing variable e of cyclic shift amount skew 1;

With the cyclic shift amount be 3 with the combination manipulative indexing variable f of cyclic shift amount skew 2;

Then, determine the value of each index variables: value is nonnegative integer, and the maximum that guarantees sequence number is less than thresholding 8, in the present embodiment, index variables a, b, c, d, e, the value of f is respectively 7,6, and 5,4,3,2;

At last, set up index value with the corresponding relation of the combination of cyclic shift amount and cyclic shift amount skew is as shown in table 7.

Table 7

index	Δ shift PUCCH	δ offset PUCCH
			7	1	0
6	2	0
			5	2	1
4	3	0
			3	3	1
2	3	2

In above embodiment, the value of index variables is all continuously arranged, in other embodiments, the value of index variables can be also non-continuous arrangement, as index variables a, b, c, d, e, the value of f is respectively 7,4,0,6,2,1, or 2,5,4,7,3,1, or 1,6,0,5,3,2 etc.That is to say, can get any 6 not identical values within 8 as index value.

As shown in Figure 5, when the cyclic shift amount that sends ascending control channel and the skew of cyclic shift amount, preserve in advance unified cyclic shift parameter list on base station and UE, comprising combination and the corresponding index value of each combination of cyclic shift amount and the skew of cyclic shift amount; During the value of cyclic shift amount and cyclic shift, choose one group of cyclic shift amount and cyclic shift from this cyclic shift parameter list in this residential quarter, UE place will be broadcasted to UE in the base station, extract corresponding index value, this index value is broadcast to UE; After UE obtains this index value, in the cyclic shift parameter list of preserving from it according to this index value, read corresponding one group of cyclic shift amount and cyclic shift.

The above is only the preferred embodiments of the present invention, is not limited to the present invention, and for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (6)

1. the collocation method of a uplink control channel configuration parameter, it is characterized in that, set up the corresponding relation of cyclic shift amount and the skew of cyclic shift amount according to the span of cyclic shift amount and the skew of cyclic shift amount, and be that each group cyclic shift amount and cyclic shift amount are offset index value of distribution, described index value is nonnegative integer, and the maximum of index value is set up the corresponding relation of index value and cyclic shift amount and cyclic shift amount offset combinations less than 8; When the span of cyclic shift amount is 1 to 3, the cyclic shift amount be 1 with the corresponding index value of combination of cyclic shift amount skew 0; The cyclic shift amount be 2 with the corresponding index value of combination of cyclic shift amount skew 0; The cyclic shift amount be 2 with the corresponding index value of combination of cyclic shift amount skew 1; The cyclic shift amount be 3 with the corresponding index value of combination of cyclic shift amount skew 0; The cyclic shift amount be 3 with the corresponding index value of combination of cyclic shift amount skew 1; The cyclic shift amount be 3 with the corresponding index value of combination of cyclic shift amount skew 2.

2. the method for claim 1, is characterized in that, when the allocation index value, get 8 with interior, do not comprise that any 6 not identical values of 8 are as index value.

3. method as claimed in claim 2, is characterized in that,

Each cyclic shift amount and the corresponding index value of cyclic shift amount offset combinations are following any one: 0,1,2,3,4,5; 5,4,3,2,1,0; 1,2,3,4,5,6; 6,5,4,3,2,1; 2,3,4,5,6,7; 7,6,5,4,3,2.

4. the sending method of a uplink control channel configuration parameter, is characterized in that,

Preserve in advance unified cyclic shift parameter list on base station and user equipment (UE), described cyclic shift parameter list comprises: the combination of cyclic shift amount and the skew of cyclic shift amount, and the corresponding index value of each combination;

When cyclic shift amount in this residential quarter, UE place and the skew of cyclic shift amount will be broadcasted to described UE in the base station, one group of cyclic shift amount and the skew of cyclic shift amount are chosen in described base station from described cyclic shift parameter list, extract index value corresponding to this combination, described index value is broadcast to described UE;

After described UE obtains described index value, read corresponding one group of cyclic shift amount and the skew of cyclic shift amount in the cyclic shift parameter list of preserving from it according to this index value;

The layoutprocedure of described cyclic shift parameter list is as follows:

(a) set up the corresponding relation of cyclic shift amount and the skew of cyclic shift amount according to the span of cyclic shift amount and the skew of cyclic shift amount;

(b) be each group cyclic shift amount and index value of cyclic shift amount skew distribution, described index value is nonnegative integer, and the maximum of index value is less than 8;

(c) set up the corresponding relation of index value and cyclic shift amount and cyclic shift amount offset combinations;

When the span of cyclic shift amount is 1 to 3, the cyclic shift amount be 1 with the corresponding index value of combination of cyclic shift amount skew 0; The cyclic shift amount be 2 with the corresponding index value of combination of cyclic shift amount skew 0; The cyclic shift amount be 2 with the corresponding index value of combination of cyclic shift amount skew 1; The cyclic shift amount be 3 with the corresponding index value of combination of cyclic shift amount skew 0; The cyclic shift amount be 3 with the corresponding index value of combination of cyclic shift amount skew 1; The cyclic shift amount be 3 with the corresponding index value of combination of cyclic shift amount skew 2.

5. method as claimed in claim 4, is characterized in that,

In described step (b), during the allocation index value, get 8 with interior, do not comprise that any 6 not identical values of 8 are as index value.

6. method as claimed in claim 5, is characterized in that,

Each cyclic shift amount and the corresponding index value of cyclic shift amount offset combinations are following any one: 0,1,2,3,4,5; 5,4,3,2,1,0; 1,2,3,4,5,6; 6,5,4,3,2,1; 2,3,4,5,6,7; 7,6,5,4,3,2.

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