WO2014073928A1

WO2014073928A1 - Method and apparatus for transmitting downlink data

Info

Publication number: WO2014073928A1
Application number: PCT/KR2013/010200
Authority: WO
Inventors: Yingyang Li; Chengjun Sun
Original assignee: Samsung Electronics Co., Ltd.; Beijing Samsung Telecom R&D Center
Priority date: 2012-11-09
Filing date: 2013-11-11
Publication date: 2014-05-15
Also published as: CN103813468A

Abstract

The present application discloses a method for transmitting PDSCH, includes: UE receiving a control signalling of a base station scheduling PDSCH transmission; the UE receiving the PDSCH scheduled by the base station; in a PRB pair containing RE used for P-BCH, reusing DMRS of the P-BCH to demodulate PDSCH information. Application of methods and apparatus of the present invention, provides a method for transmitting PDSCH in remaining RE of a PRB pair containing RE used for P-BCH and can avoid interference with P-BCH transmission.

Description

METHOD AND APPARATUS FOR TRANSMITTING DOWNLINK DATA BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention related to a wireless communication system, and more specifically, and more specifically to, when part of time frequency resources of a physical resource block pair (PRB pair) is used to transmit broadcast information of a primary broadcast channel (P-BCH), a method for transmitting other downlink information in the remaining time-frequency resources.

2. Description of the Related Art

In the 3 GPP LTE LTE-Advanced system, each wireless frame has a length of 10ms, and is divided into ten equally sized subframes. A downlink transmission time interval (TTI) is defined in one subframe. Fig. 1 shows a frame structure of the FDD system. Each downlink subframe includes two slots. For a normal cyclic prefix (CP) length, each slot contains 7 OFDM symbols; for an extended cyclic-prefix length, each slot contains 6 OFDM symbols. Fig. 2 shows a frame structure of the TDD system. Each wireless frame is equally divided into two half frames of 5ms. Each of subframe 1 and subframe 6 contains special fields, i.e., downlink pilot time slot (DwPTS), guard period (GP) and uplink pilot time slot (UpPTS). The total length of the three special fields is 1ms.

FIG. 3 shows a downlink sub-frame structure of the LTE system. The front n (n is equal to 1, 2 or 3) OFDM symbols are a downlink control channel region for transmitting user downlink control information, and includes a physical control format indicator channel (PCFICH), a Physical HARQ indicator channel (PHICH) and a physical downlink control channel (PDCCH); the remaining OFDM symbols is to transmit user downlink data, for example, Physical Downlink Shared Channel (PDSCH). The downlink physical channel is a collection of a set of resource elements (RE). RE is the smallest unit of time- frequency resources, i.e., a subcarrier in frequency and an OFDM symbol in time. The physical resource allocation granularity is a physical resource block (PRB). One PRB contains 12 consecutive subcarriers in frequency and corresponds to a time slot in time. In one subframe, two PRBs respectively located in two slots of the subframe while occupying same subcarriers are referred to as a PRB pair. RE can be used for different functions, some RE does not correspond to the above-mentioned physical channels and only used for transmitting downlink physical signals including downlink reference signals and synchronization signals. According to different functions, the LTE downlink reference signal includes cell-specific reference signal (CRS), user-specific demodulation reference signal (DMRS) and channel quality indicator reference signal (CSI-RS). RE used for DMRS can be divided into two code division multiplexing (CDM) groups, and the two CDM groups are time division and Frequency division multiplexed; within each CDM group, two DMRS ports can be further multiplexed in CDM manner.

In the LTE system, a transmission cycle of a primary broadcast channel (P-BCH) is 40ms, and can be divided into four P-BCH bursts which are mapped to slot 1 of four wireless frames in one cycle. One P-BCH burst is mapped to the front four OFDM symbols of the slot 1 in time and mapped on 72 subcarriers in the middle of the bandwidth of bandwidth in the frequency domain. In the LTE system, for a transmission mode using UE specific reference signals, UE does not receive PDSCH transmission in a PRB pair containing RE which used for synchronization channel and P-BCH.

In LTE system, downlink data transmission can be based on CRS or DMRS. PDSCH transmission based on DMRS has an advantage of facilitating interference coordination between a plurality of cells; this is because reference signal DMRS is transmitted only in allocated PRB pair resource.

The further evolution of LTE can reduce overhead of subsequent compatibility of control signalling and CRS, and reduce interference introduced due to the subsequent compatibility of control signalling and CRS at the same time, this helps to improve the spectrum utilization of UE. Since the overhead of CRS is reduced, this can also help to improve system's power efficiency. ePDCCH and PDSCH transmission of such system is usually demodulated based on DMRS, now generally referred to as new carrier type (NCT).

SUMMARY OF THE INVENTION

For a NCT system which can work independently (Standalone), all channels in the LTE require appropriate definition of alternative technologies in NCT, particularly, both of the synchronization channel and P-BCH are needed to be transmitted. In this way, in the NCT system which can work independently, there are also some PRB pairs, of which part of RE resources are occupied by synchronization channel and P-BCH, and other remaining RE can be used for PDSCH transmission, thus, how to transmit PDSCH in other RE other than RE occupied by the synchronization channel and P-BCH of NCT is a problem needed to be solved.

The present invention provides a method for, when part of time frequency resources of a PRB pair is used to transmit P-BCH, transmitting other downlink information in the remaining time-frequency resources.

A method for transmitting PDSCH includes:

UE receiving a control signalling of a base station scheduling PDSCH transmission;

the UE receiving the PDSCH scheduled by the base station; in a PRB pair containing RE used for P-BCH, reusing DMRS of the P-BCH to demodulate PDSCH information.

Preferably, a way of allocating PRB pairs used for frequency resources of P- BCH is: fixed according to a method for allocating PRB pairs when a system bandwidth contains an even number of PRB pairs.

Preferably, a mode of determining DMRS sequence of the P-BCH is: generating a long scrambling code sequence with a fixed length, using a sequence fragment of the long scrambling code sequence corresponding to PRB index range fo N^PBCH - l] rPBCH

Ι^ν' RB J or a sequence fragment of M in a middle of the long scrambling code sequence for DMRS transmission for the P-BCH, wherein M is a number of PRB pairs occupied by the P-BCH.

Preferably, the reusing DMRS of the P-BCH to demodulate PDSCH information includes:

for other broadcast information in the PDSCH except for the P-BCH, reusing the DMRS of the P-BCH to demodulate the other broadcast information;

for UE specific PDSCH in the PDSCH, using a DMRS sequence dedicated to the UE specific PDSCH to demodulate the UE specific PDSCH information.

Preferably, for a situation in which an allocation of PRB pairs used for frequency resources of the of P-BCH is consistent with an allocation of PRB pairs of a system actual bandwidth, in scheduled PRB pair resources used for transmitting the other broadcast information,

the reusing the DMRS of the P-BCH to demodulate the other broadcast information includes: for a PRB pair containing RE used for the P-BCH, using the DMRS of the P-BCH to perform channel estimation, and demodulating the other broadcast information in the PRB pair;

the method further includes: for a PRB pair not containing RE used for the P- BCH, according to a method for generating DMRS sequence for the other broadcast information generating a DMRS sequence to perform channel estimation, and demodulating the other broadcast information in the PRB pair.

the reusing the DMRS of the P-BCH to demodulate the other broadcast information includes: generating a DMRS sequence for the other broadcast information by adopting a method the same as a method for generating DMRS sequence for the P-BCH, in the PRB pair containing RE used for the P-BCH, using a DMRS demodulation symbol sequence fragment of the other broadcast information which is the same as a DMRS demodulation symbol sequence fragment of the P- BCH to perform channel estimation, and demodulating the other broadcast information in the PRB pair.

the reusing the DMRS of the P-BCH to demodulate the other broadcast information includes: in the PRB pair containing RE used for the P-BCH, using a DMRS sequence, which is transmitted in other DMRS ports except for DMRS ports of the P-BCH and dedicated to the other broadcast information and is the same as a DMRS sequence of the P-BCH to perform channel estimation and demodulating the other broadcast information in the PRB pair.

Preferably, for a situation in which an allocation of PRB pairs used for frequency resources of the of P-BCH is inconsistent with an allocation of PRB pairs of a system actual bandwidth, in scheduled PRB pair resources used for transmitting the other broadcast information,

the reusing the DMRS of the P-BCH to demodulate the other broadcast information includes: in RE of overlapping part of a DMRS pattern of the P-BCH and a DMRS pattern of the other broadcast information, reusing DMRS sequence of the P-BCH to perform channel estimation and demodulating the other broadcast information in the PRB pair; for RE which is only in the DMRS pattern of the P- BCH, the RE is not used to transmit a DMRS sequence and demodulation symbols of the other broadcast information; for RE which is only in the DMRS pattern of the other broadcast information, using DMRS sequence dedicated to the other broadcast information to perform channel estimation and demodulating the other broadcast information in the PRB pair.

Preferably, a method for generating DMRS sequence for the other broadcast information is the same or different from a method for generating DMRS sequence for the P-BCH.

the reusing the DMRS of the P-BCH to demodulate the other broadcast information includes: generating a DMRS sequence for the other broadcast information by using a method the same as a method for generating DMRS sequence for the P-BCH, in the PRB pair containing RE used for the P-BCH, using the DMRS sequence of the other broadcast information to perform channel estimation and demodulation of the other broadcast information.

Preferably, the method for generating a DMRS sequence for the other broadcast information includes: generating a long scrambling code sequence with a fixed length, and using a sequence fragment in a middle of the long scrambling code sequence corresponding to a DMRS RE number of N R^DB^L PRB pairs for DMRS transmission of the other broadcast information, wherein M is a number of PRB pairs contained in the system bandwidth.

Preferably, when using a sequence fragment in a middle of the long scrambling code sequence corresponding to a DMRS RE number of

PRB pairs for DMRS transmission of the other broadcast information, for a first RE used for CDM set of DMRS of the other broadcast information, taking DC as a boundary, a DMRS RE number of smaller subcarrier indexes is one more than a DMRS RE number of larger subcarrier indexes; for a second RE used for CDM set of DMRS of the other broadcast information, a DMRS RE number of smaller subcarrier indexes is one less than a DMRS RE number of larger subcarrier indexes. Preferably, the method further includes: when the UE receives the UE specific PDSCH scheduled by the base station, for the UE specific PDSCH, not receiving •transmission of the UE specific PDSCH in the PRB pair containing RE used for the P-BCH.

Preferably, the method further includes: when the UE receives the UE specific PDSCH scheduled by the base station, for the UE specific PDSCH, in the PRB pair containing RE used for the P-BCH, if a time frequency resource occupied by DMRS of the UE specific PDSCH scheduled by the base station conflicts with a time frequency resource of the DMRS of the P-BCH, not receiving the UE specific PDSCH in this PRB pair.

Preferably, when the UE receives the UE specific PDSCH scheduled by the base station, if DMRS ports used by the UE specific PDSCH are a subset of DMRS ports used for the P-BCH, the UE specific PDSCH scheduled by the base station is received in the PRB pair containing RE used for the P-BCH.

Preferably, for the PRB pair containing RE used for the P-BCH, in RE of overlapping part of a DMRS pattern of the UE specific PDSCH and a DMRS pattern of the P-BCH, DMRS signals of the P-BCH are reused by the UE specific PDSCH; for RE dedicated to DMRS signals of the UE specific PDSCH, a DMRS sequence is generated according to a method for generating DMRS sequence for the UE specific PDSCH or is generated according to a method for generating DMRS sequence for the P-BCH, and the generated DMRS sequence is configured to perform channel estimation and demodulation of the corresponding UE specific PDSCH; or,

a DMRS sequence is generated according to a method the same as the method for generating DMRS sequence for the P-BCH, in the PRB pair containing RE used for the P-BCH, the DMRS sequence of the UE specific PDSCH to perform channel estimation and demodulation of the UE specific PDSCH.

A base station apparatus for transmitting PDSCH includes:

a signal generation module configured to perform encoding, rate matching and modulation operation on downlink data to generate modulation symbols to be transmitted;

a multiplexing module configured to perform time-frequency resource multiplexing on the modulation symbols of PDSCH; wherein in a PRB pair containing RE used for P-BCH, modulation symbols of P-BCH and modulation symbols of PDSCH are multiplexed, and DMRS of P-BCH and DMRS of other broadcast information of the PDSCH except for the P-BCH are multiplexed; and a transmission module configured to transmit downlink signals after multiplexing.

A UE apparatus for receiving PDSCH includes:

a receiving module configured to receive downlink signals of a base station; a demultiplexing module configured to demultiplex to obtain modulation symbols of PDSCH; wherein in a PRB pair containing RE used for P-BCH, DMRS is demultiplexed, and modulation symbols of PDSCH is demultiplexed from RE other than RE occupied by P-BCH; and

a parsing module configured to perform demodulating, rate de-matching, decoding operation on the modulation symbols of PDSCH output from the demultiplexing module; wherein DMRS of P-BCH is multiplexed to demodulate other broadcast information in PDSCH except for the P-BCH.

Application of methods and apparatus of the present invention, provides a method for transmitting PDSCH in remaining RE of a PRB pair containing RE used for P- BCH and can avoid interference with P-BCH transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a schematic diagram of a frame structure of an FDD system.

Fig. 2 shows a schematic diagram of a frame structure of a TDD system.

FIG. 3 shows a schematic diagram of a downlink sub-frame structure of LTE system.

FIG. 4 shows a schematic diagram of a method for, in remaining RE other than RE occupied by P-BCH, transmitting other PDSCH according to the present application;

Fig. 5 shows a schematic diagram of DMRS patterns of P-BCH and other PDSCH in case that allocation of P-BCH and PRB pair of a system are inconsistent.

Fig. 6 shows a schematic diagram of a base station apparatus for transmitting PDSCH according to the present application; Fig. 7 shows a schematic diagram of a UE for receiving PDSCH according to the present application.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In order to make objects, technical solutions and advantages of the present application clear, the present application is hereinafter further explained in details with reference to embodiments and drawings.

For a cell which demodulates downlink control channel and PDSCH based on DMRS, when the cell works as an independent cell, P-BCH is also needed to be transmitted based on DMRS. For example, P-BCH occupies some time-frequency resources of 72 subcarriers in a middle of a system bandwidth, then DMRS used for P-BCH can also be transmitted in the middle 72 subcarriers. In a PRB pair carrying a P-BCH, in fact, P-BCH only occupies one part of time-frequency resources, and the other remaining RE can be used to transmit other PDSCH.

FIG. 4 shows a process of, in remaining RE other than RE occupied by P- BCH, transmitting other PDSCH according to the present application.

Block 401 : UE receiving a control signalling of a base station scheduling PDSCH transmissions;

Block 402: the UE receiving the PDSCH scheduled by the base station; in a PRB pair containing RE used for P-BCH, reusing DMRS of the P-BCH to demodulate PDSCH information.

In block 402, when the UE receives and demodulates PDSCH, the DMRS of the P-BCH can be reused to demodulate PDSCH. Here, the PDSCH scheduled by the base station includes other broadcast messages and UE specific PDSCH except for P-BCH.

When the DMRS of the P-BCH is reused, in different preconditions, a DMRS pattern of P-BCH and a DMRS pattern of PDSCH may be the same or different, thus, causing differences in specific processing when reusing the P-BCH. The above preconditions can include allocating PRB pair used as frequency resources of P-BCH, allocating PRB pair according to system actual bandwidth and manners of determining DMRS sequence.

Next, the issue of allocating PRB pair is first discussed.

For allocation of PRB pair of a system actual bandwidth, actually, according to a number of PRB pairs contained in the system bandwidth is even or odd, allocating methods of the PRB pair are different. If the system bandwidth contains an even number of PRB pairs, then half of the number of PRB pairs can be divided on each side of DC. If the system bandwidth contains an odd number of PRB pairs, a PRB pair in the middle of the system is divided into parts by DC, that is, there are six subcarriers on each side of DC. In other words, for allocations of PRB pairs under the two kinds of bandwidths containing even or odd PRB pairs, there are six subcarriers shifted in frequency.

For allocation of PRB pairs used for frequency resources of P-BCH, there can be following three kinds of allocating methods:

(1) Before UE detects P-BCH, the UE does not know PRB pairs contained in the system bandwidth; if a number of hypothesis tests is not increased for the UE, allocation of PRB pairs used for frequency resources of P-BCH can be independent of the allocation of PRB pairs of a system actual bandwidth. For example, the UE fixed assumes that the allocation of PRB pairs for P-BCH is implemented according to the same method as that used for allocating PRB pairs when the system bandwidth contains an even number of PRB pairs. Then, in PRB pairs allocated for P-BCH, DMRS used for P-BCH demodulation is transmitted. In this way, if the system bandwidth contains an even number of PRB pairs, obviously, the allocation of PRB pairs of P-BCH is consistent with the allocation of actual PRB pairs of the system. If the system bandwidth contains an odd number of PRB pairs, the allocation of PRB pairs adopted by P-BCH is different from the actual PRB pairs of the system, while DMRS pattern of PDSCH transmission is corresponding to allocated PRB pairs of the system actual bandwidth, this results in that DMRS pattern for P-BCH demodulation is consistent with DMRS pattern for other PDSCH transmission, i.e., equivalent to six subcarriers shifted in frequency.

(2) Another method for determining allocation of PRB pairs of P-BCH is to make the method of allocating PRB pairs used for frequency resources of P-BCH be consistent with the method of allocating PRB pairs of system actual bandwidth. In this way, when system bandwidths contain an even number of PRB pairs and an odd number of PRB pairs, respectively, DMRS patterns are inconsistent under PRB allocation methods of the two system bandwidths contain an even number of PRB pairs and an odd number of PRB pairs, respectively. Thus, by employing two blind detections, i.e., performing channel estimation and decoding P-BCH for two kinds of DMRS patterns corresponding to the bandwidths contains an even number of PRB pairs or an odd number of PRB pairs, respectively, parity of the number of PRB Contained in the bandwidth can be determined.

(3) P-SCH/S-SCH hypothesis testing can also be added to indicate 1-bit parity information of the system bandwidth in addition to indicating cell identity. According to the indicated parity of the system bandwidth, the allocation of PRB pairs of P-BCH is ensured to be consistent with the allocation of PRB pairs of the system actual bandwidth.

Adopting the second method and the third method, the method of allocating PRB pairs of P-BCH is consistent with the method of allocating PRB pairs of other PDSCH, accordingly, DMRS patterns under the two situations are also consistent, thereby simplifying system operation. In actual PDSCH transmission, DMRS of P- BCH can be directly reused, and this also simplifies the process accordingly.

In the block 402, after determining the method of allocating PRB pairs for P- BCH transmission, before performing channel estimation for P-BCH, the UE also needs to know in advance DMRS sequence used for P-BCH, i.e., DMRS sequence of P-BCH needs to be cell-specific and has nothing to do with the number of PRB of the system bandwidth. There can be a plurality of methods for determining a scrambling sequence of DMRS of P-BCH.

The first method can be similar to a method for generating DRS sequence in the downlink transmission mode 7: according to a number of modulation symbols of DMRS sequence in a PRB pair occupied by P-BCH, generating a DMRS sequence of equal length and mapping the generated DMRS sequence to each RE of DMRS of P-BCH.

Or, the second method can be similar to a method for generating modulation symbols of DMRS in the downlink transmission mode 8/9/10: first generating a long modulation symbol sequence, for example, generating the long modulation symbol sequence according to the needs of 110 PRB pairs, and using a sequence fragment

JO _NPBCH

corresponding to PRB index range F ^ RB J for DMRS transmission of P-BCH, taking a normal CP as an example, a long sequence ^r^^m^ of DMRS modulation symbols is first generated. The long sequence ^ > has a total length of ^{1 JV} RB , and is divided equally into four parts, and each part is mapped in turn to all RE used for DMRS of 1 10 PRB of one OFDM symbol; then DMRS fragment in ^r^

In JJPBCH i |

corresponding to PRB pair range i ^, RB J can be used for DMRS transmission of P-BCH. That is, a modulation symbol of DMRS in a "pRB-th PRB pair of P-BCH = w,

is: (O · 3 · /'· N ^>DL + 3 · «_PRB + m') where

1

1 / G {7,8,1 U 3}

0 p e {9,10,12,14}

/ = /'mod2 + 5

/'= 0,1,2,3

0,1,2

is a Walsh spreading code used by a DMRS port, - 0 PBCH

M 1 RB - 1

Or, the third method can be similar to a method for generating modulation symbols of DMRS in the downlink transmission mode 8/9/10: first generating a long modulation symbol sequence, for example, generating the long modulation symbol sequence according to the needs of 110 PRB pairs, and then according to the methods for allocating PRB pair adopted by P-BCH, describe the method of generating DMRS sequence of P-BCH, respectively.

If the allocation of PRB pairs for P-BCH is implemented according to the same method as that used for allocating PRB pairs when the system bandwidth contains an even number of PRB pairs, a fragment in a middle of the long jPBCH

modulation symbol sequence corresponding to the PRB pairs can be fixed used for DMRS transmission of P-BCH. Taking a normal CP as an example, a long sequence ^r^^m^ of DMRS modulation symbols is first generated. The long sequence ^r(^m) h_{as a} total length of 12iV ^^max'^DL , and is divided equally into four parts, and each part is mapped in turn to all RE used for DMRS of 110 PRB of one OFDM symbol; then DMRS fragment corresponding to PRB pair range

-· can be used for DMRS transmission of P-

BCH. A modulation symbol fragment of DMRS in a ^wPRB-th PRB pair of P-BCH can be expressed as:

k = 5m'+N™n_Fm + k'

\ p e {7,8,1 U3}

k' =

0 {9,10,12,14}

/ = /'mod 2 + 5

/' = 0,1,2,3

w'= 0,1,2

Walsh spreading code used by a DMRS port, n PRB = 0 1 N^PBCH - l

' '" ^{" w >}^ is also a value of adopting

corresponding PRB index range

If the allocation of PRB pairs for P-BCH is implemented according to the same method as that used for allocating PRB pairs when the system bandwidth contains an odd number of PRB pairs, a fragment in a middle of the long modulation 13 010200

^■13-

PBCH

symbol sequence corresponding to the PRB pairs can be fixed used for

OMRS transmission of P-BCH, for example, an index range of PRB pair can be -max,DL PBCH

RB N

+ RB N R. PBCH

B

For example, P-BCH occupies 72 subcarriers in the middle of the system, but the system bandwidth contains an odd number of PRB pairs, then the 72 subcarriers are actually in 7 PRB pairs in the

N^PBCH

middle of the system bandwidth, i.e., ^B = 7 . That is, the base station needs to transmit DMRS used for P-BCH in the 7 PRB pairs, but data RE of P-BCH actually occupies only 72 subcarriers in the middle of the bandwidth. Taking a normal CP as an example, a long sequence r(m) of DMRS modulation symbols is first generated. The long sequence

and is divided equally into four parts, and each part is mapped in turn to all RE used for DMRS of 110 PRB of one OFDM symbol; then DMRS fragment corresponding

max,DL PBCH PBCH

iV R, B N

+ RB N RB to PRB index range can be used for

DMRS transmission of P-BCH. Then, a modulation symbol fragment of DMRS in a

'PRB -th PRB pair of P-BCH can be expressed as:

where,

/: /' mod 2 + 5

0,1,2,3

w'= 0,1,2 is spreadin ode used by a DMRS port, ft PRB

means to round up, means to round down. Here,

is also a value of adopting corresponding PRB index

range

For the above third method, if the allocation of PRB pairs for P-BCH is implemented according to the same method as that used for allocating PRB pairs when the system bandwidth contains an odd number of PRB pairs, a fragment in a middle of the long modulation symbol sequence corresponding to DMRS RE number

rPBCH

of the ^' '"'· PRB pair can be fixed used for DMRS transmission of P-BCH. Taking a normal CP as an example, taking DC as a boundary, for a first RE used for CDM set of DMRS, a DMRS RE number of smaller subcarrier indexes is one more than a DMRS RE number of larger subcarrier indexes; for a second RE used for CDM set of DMRS, a DMRS RE number of smaller subcarrier indexes is one less than a DMRS RE number of larger subcarrier indexes. For example, a long sequence r(m) of DMRS modulation symbols is first generated. The long sequence r ^im *) has a total length of i2N ^^max,OL , and is divided equally into four parts, and each part is mapped in turn to all RE used for DMRS of 110 PRB of one OFDM symbol; then a sequence fragment corresponding to sequence element index range

can be used for DMRS

PBCH

transmission of RE of the first CDM set of the N ^ PRB pair of P-BCH. That is, a modulation symbol fragment of DMRS in a ^PRB -th PRB pair can be expressed as

where,

p e {7,8,1 1,13}

k - 0 p e {9,10,12,14}

/ = /'mod2 + 5

/' = 0,1,2,3

m'= 0,1,2

Walsh spreading code used by a DMRS port, n "PRB

^' is also a value of adopting corresponding sequence element index range

. A sequence fragment corresponding sequence element index range

can be used for DMRS

N PBCH

transmission of RE of the second CDM set of the ' ^RB PRB pairs of P-BCH.

A modulation symbol fragment of DMRS in a -th PRB pair can be expressed as

where,

/ = /' mod 2 + 5

./'= 0,1,2,3

m' = 0,1,2

is a Walsh spreading code used by a DMRS port, pRR ~ 0,l ..

here, is also a value of adopting corresponding sequence element index range

3ΛΓ, max,DL PBCH

RB 3iV RB + l ₊ [0,3^ - l]

Or, an index c of CDM set of DMRS can be introduced; for the above first CDM set, c is equal to 0; for the above second CDM set, c is equal to 1. Then the above formulas can be uniformly represented as: a DMRS sequence fragment in a middle of the long modulation symbol sequence corresponding to DMRS RE number

-PBCH

of the PRB pairs can be fixed used for DMRS for downlink data transmission. Taking a normal CP as an example, a long sequence ^r^^m^ of DMRS modulation symbols is first generated. The long sequence ^r^^m) has a total length of j max,DL

, and is divided equally into four parts, and each part is mapped in turn to all RE used for DMRS of 110 PRB of one OFDM symbol; then, a DMRD sequence fragment corresponding to sequence element index range max,DL

RB 3N PBCH

RB

+ C + [0,3^^CT - l]

can be used for DMRS of the N ^{' R}: PBCH

transmission of RE of the CDM set c ^B PRB pairs of P-BCH. A modulation symbol fragment of DMRS in the CDM set c of a "PRB -th PRB pair can be expressed as

/ _3Jvmax,DL

where,

k : 5m'+N n_pm + k^>

\ p e {7,8,11,13}

k':

0 p e {9,10,12,14}

= /'mod 2 + 5

*= 0,1,2,3

m'= 0,1,2

^ is a Walsh spreading code used by a DMRS port, n RS

also a value of adopting corresponding sequence element index range

In the block 402, in a PRB transmitting P-BCH, in fact, only part of RE is occupied by synchronization signal, P-BCH and et al., and other remaining RE still can be used for transmission of other PDSCH. Since what is contained in P-BCH is configuration information which is most important to a cell, thus, the above transmission of the other PDSCH cannot interfere with the transmission of P-BCH. For the transmission of other PDSCH, on one hand, if one part RE of a PRB should be used for P-BCH, then the RE cannot be used for transmission of other PDSCH any more; on another hand, if one part RE of a PRB has carried DMRS used for P- BCH demodulation, then the RE cannot be used to carry other DMRS used for other PDSCH demodulation any more. The above other PDSCH transmission except for P-BCH transmission can be divided into two kinds. The first kind is other broadcast information except for P- BCH, such as SIB, paging message, random access response (RAR) message, and et al.; similar to P-BCH, these messages are also to cover users of the whole cell. The second kind is UE specific PDSCH; the UE specific PDSCH is scheduled for each UE, respectively. A precoding matrix of DMRS ports of the UE specific PDSCH is also set for each UE, respectively.

For other PDSCH except for P-BCH, DMRS can be transmitted by adopting a method similar to a DMRS generating method in downlink transmission mode 9/10 of an existing system. Or, for other PDSCH except for P-BCH, DMRS can also be transmitted by adopting a method consistent with a method for generating DMRS for P-BCH, this can ensure that at least in RE of overlapping part of DMRS pattern of P- BCH and DMRS pattern of other PDSCH, DMRS modulation symbol sequence fragments are the same. Further, other broadcast information except for P-BCH and UE specific PDSCH can also be distinguished; for other broadcast information except for P-BCH, DMRS can also be transmitted by adopting a method consistent with a method for generating DMRS for P-BCH; for UE specific PDSCH, DMRS can be transmitted by adopting a method similar to a DMRS generating method in downlink transmission mode 9/10 of the existing system. Adopting this method can facilitate other broadcast information except for P-BCH to reuse DMRS signal of P- BCH, and can also reuse the existing DMRS generating method to transmit DMRS of the UE specific PDSCH, thereby reducing complexity.

In order to distinguish other broadcast information except for P-BCH and UE specific PDSCH, for a system which demodulates downlink control channel and data channel based on DMRS, accordingly, two downlink transmission modes can be defined. One transmission mode is to process other broadcast information except for P-BCH, and usually adopts transmit diversity technique based on DMRS demodulation to improve reliability, for example, SFBC, random precoding, or other methods. Another transmission mode is to process UE specific PDSCH, and this transmission mode can be the same as a method for transmitting dynamic PDSCH based on DMRS of the existing system; for example, the downlink transmission mode 9/10 of the existing system, a precoded reference signal can be transmitted through a DMRS port, and PDSCH and DMRS are precoded by using the same precoding matrix. For other broadcast information except for P-BCH in the system, since the information is also to cover users of the whole cell, the information can reuse DMRS sequence of P-BCH.

Assuming that P-BCH adopts SFBC transmit diversity technique and occupies

N^PBCH

the ^PRB PRB pairs in the middle of the bandwidth, two DMRS ports of the ^PBCH

PRB B pairs can be occupied to transmit reference signals. For a DMRS

j PBCH

port, all the Rg p_a{_{rs can ai}jopt the same precoding matrix, so that jyPBCH

joint channel estimation can be performed in the ^PRB PRB pairs to enhance channel estimation performance; or, the ^PRB PRB pairs can further be divided

j PBCH

into groups, for example, PRB is equal to 6 and can be divided into two groups 3+3, so that three consecutive PRB pairs of each group have the same precoding matrix so as to perform joint channel estimation; the two groups can adopt different precoding matrixes, thereby obtaining spatial diversity gain. For the later method, if the other broadcast information does not adopt the SFBC transmit diversity technique and adopts other technique such as a random precoding matrix method, since the precoding matrix of each group is different, when other broadcast information is transmitted in these PRB pairs used for P-BCH, thereby improving spatial diversity gain.

Assuming that P-BCH adopts random precoding transmit diversity technique and occupie PRB pairs in the middle of the bandwidth, two DMRS ports of the

PRB pairs can be occupied to transmit reference signals. For one DMRS port, a precoding matrix adopted in each PRB pair can be different, j^ PBCH

thereby maximizing spatial diversity gain; or, the ^PRB PRB pairs can further be divided into groups, for example,

is equal to 6 and can be divided into three groups 2+2+2, so that two consecutive PRB pairs of each group have the same precoding matrix so as to perform joint channel estimation to enhance channel estimation performance; the three groups of PRB pairs can adopt different precoding matrixes, thereby obtaining spatial diversity gain. For the later method, other broadcast information can reuse DMRS sequence of P-BCH, and this can also accordingly use the joint channel estimation to improve channel estimation performance.

For other broadcast information except for P-BCH, a specific way of reusing DMRS sequence of P-BCH is hereinafter described in details.

When the allocation of PRB pairs of frequency resources of P-BCH is consistent with the allocation of PRB pairs of the system actual bandwidth, since the method for allocating PRB pairs for P-BCH transmission is consistent with the method for allocating PRB pairs for PDSCH, thus, DMRS pattern of P-BCH is exactly the same as DMRS pattern of PDSCH, and DMRS sequence of P-BCH can be directly reused. When adopting the above first kind of method for allocating PRB pairs for P-BCH, it is fixed set that the allocation of PRB pairs for P-BCH is implemented according to a situation in which the system bandwidth contains an even number of PRB pairs, and the current system actual bandwidth contains an even number of PRB pairs. Or, adopting the above second or third kind of method for allocating PRB pairs for P- BCH, both can make the allocation of PRB pairs for P-BCH be consistent with the allocation of PRB pairs of the system actual bandwidth.

A first kind of method for determining DMRS sequence of other broadcast information except for P-BCH is described below. In PRB pair resources scheduling transmission of other broadcast information, for a PRB pair containing RE used for P-BCH, DMRS sequence of P-BCH can be directly used to perform channel estimation; while for a PRB pair not containing RE used for P-BCH, a DMRS sequence is generated according to a DMRS sequence generating method used for other broadcast information except for P-BCH and is used to perform channel estimation. For example, the DMRS generating method used for other broadcast information except for P-BCH can be the DMRS generating method of the downlink transmission mode 9/10 of the existing system. Taking a normal CP as an example, a

DMRS modulation symbol sequence can be recorded as ^r^^m^ and has a total length of 12

contains DMRS fragments of 110 PRB pairs, is divided equally into four parts, and each part is mapped in turn to all RE used for DMRS of 110 PRB of one OFDM symbol; then a DMRS modulation symbol of the "^pRB -th PRB pair of the system bandwidth can be ? - v_P (O^■ 3 · 1V ^D + 3 · «_PRB + trt)

ΐΐ ^~

B 0 ·^> 1"^>' · · N K^DL —

PR B 1 _s N R^DB^L j_{s a} number of PRB pairs of the system bandwidth. Adopting this method, in PRB pair resources scheduling transmission of other broadcast information, the PRB pair containing RE used for P-BCH and other PRB pair adopt different methods for generating DMRS.

A second kind of method for determining DMRS sequence of other broadcast information except for P-BCH is described below. For P-BCH and other broadcast information, a consistent DMRS modulation symbol generating method can be adopted, thereby ensuring that in a PRB pair containing RE used for P-BCH, a DMRS modulation symbol sequence fragment of other broadcast information is the same as a DMRS modulation symbol sequence fragment of P-BCH. For example, similar to the above third kind of method for generating DMRS for P-BCH, if the allocation of PRB pairs for P-BCH is implemented according to the same method as that used for allocating PRB pairs when the system bandwidth contains an even number of PRB pairs, a long modulation symbol sequence is first generated by using a method consistent with P-BCH, for example, generating the long modulation symbol sequence of DMRS according to the needs of 110 PRB pairs, and a sequence fragment in a middle of the long modulation symbol sequence corresponding to

N ^RDBL PRB pairs is fixed used for DMRS transmission. Taking a normal CP as an example, a long sequence r(wi ^J) of DMRS modulation symbols is first generated.

The long sequence ^r^^m^ has a total length of 12i ^^mBax,DL , and is divided equally into four parts, and each part is mapped in turn to all RE used for DMRS of 110 PRB of one OFDM symbol. For the situation that the system bandwidth contains an even number of PRB pairs, a DMRS fragment corresponding to PRB pair index range

PRB pairs of the system bandwidth. A modulation symbol fragment of DMRS in a

PRB -th PRB pair of the system bandwidth can be expressed as: al"/

k = Sm^N^n^ + V

1 p ε {7,8,1 U3}

0 p€ {9,10,12,14}

/ = /'mod 2 + 5

/'= 0,1,2,3

rri= 0,1,2

a Walsh spreading code used by a DMRS port, ft PRB = 0,\,...N Rs Here, ^{p 7} is also a value of adopting

max,DL

RB + RB RB 1

corresponding PRB index range ^{~ L ~ ~ J} . Adopting this method for generating DMRS modulation symbol sequence, in PRB pair resources scheduling transmission of other broadcast information, no matter whether or not allocated PRB pair containing RE used for P-BCH, DMRS sequence can be directly regarded as generated according to the above method for generating DMRS sequence. In other words, this method can automatically ensure that if one part of RE of one PRB pair of PRB pair resources which are used for transmission of other broadcast information, is used for P-BCH, DMRS sequence obtained according to this method is the same as DMRS sequence of P-BCH. When the UE demodulates other broadcast information, the UE can simply perform channel estimation only according to the DMRS sequence generated by the above method, and does not distinguish as to whether a PRB pair contains RE used for P-BCH.

A third kind of method for determining DMRS sequence of other broadcast information except for P-BCH is described below. In PRB pair resources scheduling transmission of other broadcast information, for a PRB pair containing RE used for P-BCH, adopting a DMRS sequence which is the same as the DMRS sequence of P- BCH is adopted, but specifically transmitting DMRS of other broadcast information at different DMRS ports. For example, if P-BCH occupies DMRS ports 8 and 10, then DMRS ports 7 and 9 both can be used to transmit DMRS of other broadcast information. The reason why it is required to reuse DMRS sequence of P-BCH here is to ensure that in each CDM RE set, DMRS of P-BCH and other broadcast information are orthogonal so as to ensure that channel estimation performance of P- BCH is not affected and guarantee channel estimation performance of other broadcast information at the same time. Adopting this method, for other broadcast information except for P-BCH, allows configuring to use a precoding matrix different from P-BCH during DMRS transmission. Or, if DMRS of P-BCH only occupies one CDM RE set such as DMRS ports 7 and 8, then other broadcast information can occupy another one CDM RE set such as DMRS ports 9 and 10. In this way, DMRS sequence may be not subject to restrictions of P-BCH, and can fully use DMRS sequence used for other broadcast information in accordance with the definition of the system, and is configured to use a precoding matrix different from P-BCH.

For a situation in which the allocation of PRB pairs of P-BCH is inconsistent with the allocation of actual PRB pairs of the system, for example, adopting the above first kind of method for allocating PRB pairs for P-BCH, it is fixed set that the allocation of PRB pairs for P-BCH is implemented according to a situation in which the system bandwidth contains an even number of PRB pairs; when the system bandwidth contains an odd number of PRB pairs, time-frequency locations of DMRS pattern used for P-BCH demodulation and DMRS pattern of other broadcast information are not completely overlapped. As shown in Fig. 5, DMRS pattern of P-BCH is to make DC component not in a frequency range of any one PRB; while for DMRS pattern of other broadcast information, taking DC as a center, frequency of one PRB pair in the middle of the system bandwidth is divided equally into two parts. As shown in Fig. 5, in some RE, DMRS pattern corresponding to two kinds of method for allocating PRB pairs are overlapped, such RE carries DMRS of P-BCH and is also used as a DMRS signal of other broadcast information at the same time; in these overlapped RE, other broadcast information can reuse DMRS signals of P-BCH. For other RE, they are only in the DMRS pattern of P-BCH and are used for DMRS transmission, and such RE is not used to transmit other broadcast information. For another RE, they are only in the DMRS pattern of other broadcast information and are used for DMRS transmission, and such RE are DMRS signals dedicated to other broadcast information. As shown in Fig. 5, for the situation in which the bandwidth contains an even number of PRB pairs, in PRB pairs for carrying P-BCH of subframes, except for RE occupied by DMRS of P-BCH, other RE are also used as DMRS and are dedicated to demodulation of other broadcast information

The first kind of method for determining DMRS sequence of other broadcast information except for P-BCH is described below. In PRB pair resources scheduling transmission of other broadcast information, for a PRB pair not containing RE used for P-BCH, a DMRS sequence is generated according to the DMRS sequence generating method used for other broadcast information except for P-BCH and is used to perform channel estimation; for a PRB pair containing RE used for P-BCH, in RE of overlapping part of DMRS pattern of other broadcast information and DMRS pattern of P-BCH, DMRS signal of P-BCH can be directly reused. In RE dedicated to DMRS signals of other broadcast information, a DMRS sequence can be generated according to the DMRS sequence generating method used for other broadcast information except for P-BCH, and can also be generated according to the DMRS sequence generating method for P-BCH, and then is used to perform channel estimation. Adopting this method, in PRB pair resources scheduling transmission of other broadcast information, the PRB pair containing RE used for P- BCH and other PRB pair adopt different methods for generating DMRS.

The second kind of method for determining DMRS sequence of other broadcast information except for P-BCH is described below. For P-BCH and other broadcast information, a consistent OMRS modulation symbol generating method can be adopted, thereby ensuring that in a PRB pair containing RE used for P-BCH, DMRS modulation symbols of RE in overlapping part of DMRS pattern of other broadcast information and DMRS pattern of P-BCH are the same. Similar to the above third kind of method for generating DMRS for P-BCH, a long modulation symbol sequence is first generated by using a method consistent with P-BCH, for example, generating the long modulation symbol sequence of DMRS according to the needs of 110 PRB pairs, and a sequence fragment in a middle of the long modulation symbol sequence corresponding to the DMRS RE number of the PRB pairs is fixed used for DMRS for downlink data transmission. Taking a normal CP as an example, taking DC as a boundary, for a first RE used for CDM set of DMRS, a DMRS RE number of smaller subcarrier indexes is one more than a DMRS RE number of larger subcarrier indexes; for a second RE used for CDM set of DMRS, a DMRS RE number of smaller subcarrier indexes is one less than a DMRS

(tn)

RE number of larger subcarrier indexes. For example, a long sequence ⁷ of DMRS modulation symbols is first generated by using a method consistent with P-

BCH. The long sequence r( ^m) ' has a total length of 12N ^Z^X'OL , and is divided equally into four parts, and each part is mapped in turn to all RE used for DMRS of 110 PRB of one OFDM symbol; then for the first RE used for CDM set of DMRS, a sequence fragment corresponding to sequence element index range max,DL DL

3JST, RB 3N DL

RB 3N RB

- 1

can be used for DMRS transmission of

_NDL

RE of the first CDM set of the ^RB -th PRB pair of the system bandwidth. That is, a modulation symbol fragment of DMRS in a "PRB -th PRB pair can be expressed as

where, P T/KR2013/010200

-27-

k = +N™n_?RB + k^x

/ = /' mod2 + 5

/' = 0,1,2,3

sed by a DMRS port, ⁿ

also a value of adopting corresponding sequence element index

3JV R- max,DL

B 3N DL

RB 3N DL

RB -1

range . For the second RE used for CDM set of DMRS, a sequence fragment corresponding to sequence element index

can be used for DMRS transmission of

N DL

RE of the second CDM set of the ^ PRB pairs of the system bandwidth. That is, a modulation symbol fragment of DMRS in a "PRB -th PRB pair can be expressed as

, where,

\ p e {7,8,11,13}

0 {9,10,12,14}

/ = /'mod 2 + 5

/'= 0,1,2,3

0,1,2 p is a Walsh spreading code used by a DMRS port, ⁿPRB

is also a value of adopting corresponding sequence

element index range

Or, an index c of CDM set of DMRS can be introduced; for the above first CDM set, c is equal to 0; for the above second CDM set, c is equal to 1. Then the above formulas can be uniformly represented as: similar to the above third kind of method for generating DMRS for P-BCH, a long modulation symbol sequence is first generated by using a method consistent with P-BCH; for example, according to the method for generating modulation symbols of DMRS in the downlink transmission mode 8/9/10 and according to the needs of 1 10 PRB pairs, generating the long modulation symbol sequence of DMRS; and a DMRS sequence fragment in

_NDL

a middle of the long modulation symbol sequence corresponding to ^ PRB pairs is fixed used for DMRS transmission for downlink data transmission. Taking a normal CP as an example, a long sequence ^r^^m^ of DMRS modulation symbols is first generated. The long sequence r(m) ⁷ has a total length of ^'12iY"^ax'^DL , and is divided equally into four parts, and each part is mapped in turn to all RE used for DMRS of 110 PRB of one OFDM symbol; then a DMRS fragment corresponding

to sequence element index can be used for DMRS transmission

pairs of the system bandwidth. A modulation symbol fragment of DMRS in the CDM set c

n as

where,

k : 5rn'+N™n_PRB + k^<

1 p e {7,8,1 1,13}

{o p e {9,10,12,14}

/ = /'mod 2 + 5

/' = 0,1,2,3

m' = 0,1,2 n PRB

corresponding

Adopting the above second kind of method for generating DMRS modulation symbol sequence, in PRB pair resources scheduling transmission of other broadcast information, no matter whether or not allocated PRB pair containing RE used for P- BCH, DMRS sequence can be directly regarded as generated according to the above method for generating DMRS sequence. In other words, this method can automatically ensure that if one part of RE of one PRB pair of PRB pair resources which are used for transmission of other broadcast information, is used for P-BCH, in RE of overlapping part of DMRS patterns, DMRS sequence obtained according to this method is the same as DMRS sequence of P-BCH. When the UE demodulates other broadcast information, the UE can simply perform channel estimation only according to the DMRS sequence generated by the above method, and does not distinguish as to whether a PRB pair contains RE used for P-BCH.

The transmit diversity technique adopted by P-BCH can be SFBC or random beamforming, et al. The transmit diversity technique adopted by other broadcast information can be the same or different from that of P-BCH, but DMRS sequence used for other broadcast information can be determined according to the above method.

When it is needed to transmit UE specific PDSCH in a PRB pair containing RE of P-BCH, since the PDSCH is scheduled for each UE, and a precoding matrix of DMRS ports of the PDSCH is also set for each UE, respectively; while DMRS of P- BCH is cell-specific, this is because P-BCH needs to be accepted by all UE within a cell; thus, it is generally not suitable to use DMRS ports of P-BCH for dynamic PDSCH transmission of UE.

For UE specific PDSCH, in order to avoid interference with P-BCH which results in performance degradation of P-BCH, four methods for processing UE specific PDSCH in PRB pair containing RE used for P-BCH are described hereinafter.

The first method is that, so long as a time frequency resource used for P-BCH is contained in one PRB pair of PDSCH of UE, then, such a PRB pair does not transmit PDSCH of the UE, and thus there is no need to transmit DMRS, thereby avoiding interference with DMRS of P-BCH.

Or, the second method is that, when a time frequency resource used for P- BCH is contained in one PRB pair of PDSCH of the UE, and a time frequency resource occupied by DMRS of PDSCH also conflicts with a time frequency resource of DMRS of P-BCH, then such a PRB pair does not transmit PDSCH of the UE. In other words, even when a time frequency resource used for P-BCH is contained in one PRB pair of PDSCH of the UE, but the time frequency resource occupied by DMRS of PDSCH does not conflict with the time frequency resource of DMRS of P-BCH, channel estimation can still be performed based on this DMRS, and PDSCH of the UE can be received in RE which is of this PRB pair and is not used for P-BCH.

Or, the third method is that, DMRS of P-BCH is transmitted in one PRB pair containing time frequency resources used for P-BCH, if the base station schedules PDSCH of the UE, and DMRS ports used for scheduling PDSCH are a subset of DMRS ports used for P-BCH, then based on channel estimation of DMRS of this subset, PDSCH of the UE can be transmitted in RE which is of this PRB pair and is not used for P-BCH. On the contrary, if DMRS ports used for scheduling PDSCH of the UE are not a subset of DMRS ports used for P-BCH, then PDSCH of the UE is not transmitted. For example, assuming that P-BCH occupies DMRS ports 7 and 9, if the base station schedules a single stream PDSCH transmission based on the DMRS port 7 of the UE in one PRB pair containing time frequency resources used for P- BCH, then in this PRB pair, the UE can reuse DMRS port 7 of P-BCH to perform channel estimation, thereby performing single stream PDSCH transmission.

For the third method, a method of transmitting DMRS of UE specific PDSCH is further described. In PRB pair resources for scheduling UE specific PDSCH, for a PRB pair not containing RE used for P-BCH, a DMRS sequence is generated according to a method for generating DMRS sequence for UE specific PDSCH and is used to perform channel estimation. For a PRB pair containing RE used for P- BCH, in RE of overlapping part of DMRS pattern of UE specific PDSCH and DMRS pattern of P-BCH, DMRS signals of P-BCH can be directly reused. If there is RE dedicated to DMRS signals of UE specific PDSCH, a DMRS sequence can be generated according to the method for generating DMRS sequence for UE specific PDSCH, and can also be generated according to the method for generating DMRS sequence for P-BCH, and then is used to perform channel estimation. Adopting this method, in PRB pair resources scheduling transmission of UE specific PDSCH, the PRB pair containing RE used for P-BCH and other PRB pair adopt different methods for transmitting DMRS. Or, for P-BCH and UE specific PDSCH, by adopting a consistent method for generating DMRS demodulation symbols, can ensure that in PRB pair containing RE used for P-BCH, at least in RE of overlapping part of DMRS pattern of UE specific PDSCH and DMRS pattern of P-BCH, DMRS modulation symbols are the same. Adopting this method for generating DMRS modulation symbol sequence, in PRB pair resources scheduling transmission of UE specific PDSCH, no matter whether or not allocated PRB pair containing RE used for P-BCH, DMRS sequence can be directly regarded as generated according to the method for generating DMRS sequence for UE specific PDSCH. When the UE demodulates UE specific PDSCH, the UE can simply perform channel estimation only according to the DMRS sequence generated according to the UE specific PDSCH, and does not distinguish as to whether a PRB pair contains RE used for P- BCH.

Or, the forth method is that, in a PRB pair containing time frequency resource used for P-BCH, so long as the UE schedules PDSCH of the UE, the UE performs channel estimation in this PRB pair based on DMRS ports of the scheduled PDSCH and receives PDSCH. A base station scheduler needs to ensure that interference introduced due to scheduling UE specific PDSCH is very small with P-BCH. PDSCH can be transmitted only in RE which of the PRB pair and is not used for P- BCH, or PDSCH can be transmitted in all RE of the PRB pair.

Corresponding to the above methods, the present application provides corresponding apparatus, respectively, which will be described in below.

Fig. 6 shows a schematic diagram of a base station apparatus for transmitting PDSCH according to the present application. The apparatus includes a signal generation module 601, a multiplexing module 602 and a transmission module 603. The signal generation module 601 is to perform encoding, rate matching, and modulation and other operations on downlink data, thereby generating modulation symbols to be transmitted.

The multiplexing module 602 is to perform time-frequency resource multiplexing on the modulation symbols output from the signal generation module 601; particularly, in PRB pair containing RE used for P-BCH, according to the above methods, to multiplex modulation symbols of P-BCH and modulation symbols of PDSCH, and multiplex DMRS of P-BCH and OMRS of PDSCH.

The transmission module 603 is to transmit downlink signals after multiplexing.

Fig. 7 shows a schematic diagram of a UE for receiving PDSCH according to the present application. The apparatus includes a receiving module 701, a demultiplexing module 702 and a parsing module 703.

The receiving module 701 is to receive downlink signals of a base station.

The demultiplexing module 702 is to demultiplex to obtain modulation symbols of PDSCH. Particularly, in PRB pair containing RE used for P-BCH, according to the above methods, to demultiplex DMRS, and to demultiplex modulation symbols of PDSCH from RE other than RE occupied by P-BCH.

The parsing module 703 is to perform demodulating, rate de-matching, decoding and other operations on the modulation symbols of PDSCH output from the demultiplexing module 702; particularly, according to the above methods, to multiplex DMRS of P-BCH to demodulate PDSCH information.

Application of the methods and apparatus of the present invention, provides a method for transmitting PDSCH in remaining RE of a PRB pair containing RE used for P-BCH and can avoid interference with P-BCH transmission.

The foregoing are only preferred embodiments of the present invention and are not for use in limiting the present invention. All modifications, equivalent replacements or improvements in accordance with the spirit and principles of the present invention shall be included in the protection scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. A method for transmitting PDSCH, comprising:

2. The method of claim 1, wherein a way of allocating PRB pairs used for frequency resources of P-BCH is: fixed according to a method for allocating PRB pairs when a system bandwidth contains an even number of PRB pairs.

3. The method of claim 1, wherein a mode of determining DMRS sequence of the P-BCH is: generating a long scrambling code sequence with a fixed length, using a sequence fragment of the long scrambling code sequence corresponding to PRB

\_{0 N}PBCH _ _NPBCH index range ^{L J} or a sequence fragment of ^{Λ >} in a middle of the long scrambling code sequence for DMRS transmission for the P-BCH,

T PBCH

wherein ^Λ£> is a number of PRB pairs occupied by the P-BCH.

4. The method of claim 1, wherein the reusing DMRS of the P-BCH to demodulate PDSCH information comprises:

for other broadcast information in the PDSCH except for the P-BCH, reusing the DMRS of the P-BCH to demodulate the other broadcast information; for UE specific PDSCH in the PDSCH, using a DMRS sequence dedicated to the UE specific PDSCH to demodulate the UE specific PDSCH information.

5. The method of claim 4, wherein for a situation in which an allocation of PRB pairs used for frequency resources of the of P-BCH is consistent with an allocation of PRB pairs of a system actual bandwidth, in scheduled PRB pair resources used for transmitting the other broadcast information,

the reusing the DMRS of the P-BCH to demodulate the other broadcast information comprises: for a PRB pair containing RE used for the P-BCH, using the DMRS of the P-BCH to perform channel estimation, and demodulating the other broadcast information in the PRB pair;

the method further comprises: for a PRB pair not containing RE used for the P-BCH, according to a method for generating DMRS sequence for the other broadcast information generating a DMRS sequence to perform channel estimation, and demodulating the other broadcast information in the PRB pair.

6. The method of claim 4, wherein for a situation in which an allocation of PRB pairs used for frequency resources of the of P-BCH is consistent with an allocation of PRB pairs of a system actual bandwidth, in scheduled PRB pair resources used for transmitting the other broadcast information,

the reusing the DMRS of the P-BCH to demodulate the other broadcast information comprises: generating a DMRS sequence for the other broadcast information by adopting a method the same as a method for generating DMRS sequence for the P- BCH, in the PRB pair containing RE used for the P-BCH, using a DMRS demodulation symbol sequence fragment of the other broadcast information which is the same as a DMRS demodulation symbol sequence fragment of the P-BCH to perform channel estimation, and demodulating the other broadcast information in the PRB pair.

7. The method of claim 4, wherein for a situation in which an allocation of PRB pairs used for frequency resources of the of P-BCH is consistent with an allocation of PRB pairs of a system actual bandwidth, in scheduled PRB pair resources used for transmitting the other broadcast information,

the reusing the DMRS of the P-BCH to demodulate the other broadcast information comprises: in the PRB pair containing RE used for the P-BCH, using a DMRS sequence, which is transmitted in other DMRS ports except for DMRS ports of the P-BCH and dedicated to the other broadcast information and is the same as a DMRS sequence of the P-BCH to perform channel estimation and demodulating the other broadcast information in the PRB pair.

8. The method of claim 4, wherein for a situation in which an allocation of PRB pairs used for frequency resources of the of P-BCH is inconsistent with an allocation of PRB pairs of a system actual bandwidth, in scheduled PRB pair resources used for transmitting the other broadcast information,

the reusing the DMRS of the P-BCH to demodulate the other broadcast information comprises: in RE of overlapping part of a DMRS pattern of the P-BCH and a DMRS pattern of the other broadcast information, reusing DMRS sequence of the P-BCH to perform channel estimation and demodulating the other broadcast information in the PRB pair; for RE which is only in the DMRS pattern of the P-BCH, the RE is not used to transmit a DMRS sequence and demodulation symbols of the other broadcast information; for RE which is only in the DMRS pattern of the other broadcast information, using DMRS sequence dedicated to the other broadcast information to perform channel estimation and demodulating the other broadcast information in the PRB pair.

9. The method of claim 8, wherein a method for generating DMRS sequence for the other broadcast information is the same or different from a method for generating DMRS sequence for the P-BCH.

10. The method of claim 4, wherein for a situation in which an allocation of PRB pairs used for frequency resources of the of P-BCH is inconsistent with an allocation of PRB pairs of a system actual bandwidth, in scheduled PRB pair resources used for transmitting the other broadcast information,

the reusing the DMRS of the P-BCH to demodulate the other broadcast information comprises: generating a DMRS sequence for the other broadcast information by using a method the same as a method for generating DMRS sequence for the P-BCH, in the PRB pair containing RE used for the P-BCH, using the DMRS sequence of the other broadcast information to perform channel estimation and demodulation of the other broadcast information.

11. The method of claim 10, wherein the method for generating a DMRS sequence for the other broadcast information comprises: generating a long scrambling code sequence with a fixed length, and using a sequence fragment in a middle of the long scrambling code sequence corresponding to a DMRS RE number of ^I RB PRB pairs for DMRS transmission of the other broadcast information, wherein &B is a number of PRB pairs contained in the system bandwidth.

12. The method of claim 11, wherein when using a sequence fragment in a middle of the long scrambling code sequence corresponding to a DMRS RE number of N ^RDBL PRB pairs for DMRS transmission of the other broadcast information, for a first RE used for CDM set of DMRS of the other broadcast information, taking DC as a boundary, a DMRS RE number of smaller subcarrier indexes is one more than a DMRS RE number of larger subcarrier indexes; for a second RE used for CDM set of DMRS of the other broadcast information, a DMRS RE number of smaller subcarrier indexes is one less than a DMRS RE number of larger subcarrier indexes.

13. The method of claim 4, wherein the method further comprises: when the UE receives the UE specific PDSCH scheduled by the base station, for the UE specific PDSCH, not receiving transmission of the UE specific PDSCH in the PRB pair containing RE used for the P-BCH.

14. The method of claim 4, wherein the method further comprises: when the UE receives the UE specific PDSCH scheduled by the base station, for the UE specific PDSCH, in the PRB pair containing RE used for the P-BCH, if a time frequency resource occupied by DMRS of the UE specific PDSCH scheduled by the base station conflicts with a time frequency resource of the DMRS of the P-BCH, not receiving the UE specific PDSCH in this PRB pair.

15. The method of claim 4, wherein when the UE receives the UE specific PDSCH scheduled by the base station, if DMRS ports used by the UE specific PDSCH are a subset of DMRS ports used for the P-BCH, the UE specific PDSCH scheduled by the base station is received in the PRB pair containing RE used for the P-BCH.

16. The method of claim 15, wherein

for the PRB pair containing RE used for the P-BCH, in RE of overlapping part of a DMRS pattern of the UE specific PDSCH and a DMRS pattern of the P- BCH, DMRS signals of the P-BCH are reused by the UE specific PDSCH; for RE dedicated to DMRS signals of the UE specific PDSCH, a DMRS sequence is generated according to a method for generating DMRS sequence for the UE specific PDSCH or is generated according to a method for generating DMRS sequence for the P-BCH, and the generated DMRS sequence is configured to perform channel estimation and demodulation of the corresponding UE specific PDSCH;

or,

17. A base station apparatus for transmitting PDSCH, comprising:

18. A UE apparatus for receiving PDSCH, comprising: