CN101399647A - Method for configuring hybrid automatic retransmission request indication channel - Google Patents

Abstract

The invention provides a method for configuring a hybrid automatic repeat request indication channel. The method mapping ACK/NACK information to mini-CCE provides a transmission mechanism of ACK/NACK when a base station configures four antennae; the method for mapping CCE to ACK/NACK extended code reduces district interface of an ACK/NACK channel; and the method for configuring a distributed channel enhances the transmission performance of the distributed channel.

Description

The method of configuration hybrid automatic repeat request indication channel

Technical field

The present invention relates to wireless communication system, relate to the method for the configuration hybrid automatic repeat request indication channel in wireless communication system in particular.

Background technology

Now, 3GPP standardization body has set about beginning its existing system standard is carried out long-term evolution (LTE).In the middle of numerous physical layer transmission technology, be the focus of research based on the downlink transfer technology of OFDM (OFDM) with based on the uplink technology that single-carrier frequency division multiple access inserts (SCFDMA).At present, two kinds of hardwood structures are arranged in LTE: i.e. Class1 frame structure (Type 1 Frame Structure) and type 2 frame structures (Type 2 Frame Structure).Two kinds of duplex modes of FDD and TDD are arranged in the Class1 frame structure, and have only TDD duplex mode in type 2 frame structures.Be problem and the method for the present invention that example is described existing method with LTE Class1 FDD system below, described method is equally applicable to LTE TDD system.

According to the discussion result of current LTE, Fig. 1 is the downlink frame structure of LTE Class1, and radio frames (radio frame) time span (101-103) is 10ms; Each frame is divided into a plurality of time slots (slot) (104-107), and present hypothesis is that each radio frames comprises 20 time slots, and time slots length is 0.5ms; For the FDD duplex mode, each time slot comprises a plurality of OFDM symbols again, and for the TDD duplex mode, each descending time slot also comprises a plurality of OFDM symbols.According to present hypothesis, the time span of effective OFDM symbol is about 66.7 μ s in the LTE system.The CP of OFDM symbol has two kinds of length, promptly general CP (normal CP) and lengthening CP (extendedCP), and the time span of general CP is approximately 4.7 μ s, the about 16.7 μ s of time span of lengthening CP.General CP time slot (108) comprises 7 OFDM symbols, and lengthening CP time slot (109) comprises 6 OFDM symbols.According to present discussion result, continuous two time slots constitute subframes (subframe), and Transmission Time Interval (TTI) is 1ms, equal the time span of a subframe.

Discussion result according to current LTE, preceding n OFDM symbol of a subframe is used to transmit down control channel, and the control channel here comprises Physical Control Format Indicator Channel (PCFICH), Physical Downlink Control Channel (PDCCH) and physical mixed automatic re-transmission indicating channel (PHICH).These control channels need be distributed in the whole bandwidth fully, thereby obtain sufficient frequency diversity gain.To LTE Class1 FDD frame structure, n is smaller or equal to 3.To the TDD system of LTE, according to the quantity of the control information of needs transmission in the subframe, the value of n might be greater than 3.

According among the current LTE to the discussion result of control channel, the basic composition unit of control channel is called small-sized control channel unit (mini-CCE), it is corresponding continuous 4 available resource units (RE) on frequency domain.The available RE does not here comprise the RE that downlink reference signal takies and the RE of other reservations.PCFICH is mapped to 4 mini-CCE, and these 4 mini-CCE are distributed in the whole bandwidth.PHICH is mapped to 3 mini-CCE, and these 3 mini-CCE are distributed in the whole bandwidth; Note currently still whether needing to be mapped to 4 mini-CCE at the scene PHICH that discusses the single transmit antenna.To PDCCH, a plurality of mini-CCE are combined into CCE, are the mapping PDCCH of unit then with CCE.For example to the system of 5MHz, CCE comprises 36 RE, promptly is made up of 9 mini-CCE.

According to the discussion result of current LTE, when the two transmitting antenna of base station configuration, the method for transmit diversity is space frequency block coding (SFBC).The principle of SFBC is on two subcarriers in two antennas and same OFDM symbol signal to be carried out combined coding and send.When base station configuration four transmitting antennas, the method for transmit diversity is space frequency block coding and frequency inverted transmit diversity (SFBC+FSTD).To the configuring condition of four transmitting antennas, note sends reference signal in first OFDM symbol of subframe two antennas are respectively antenna 1 and antenna 2; And two antennas of note transmission reference signal in second OFDM symbol of subframe are respectively antenna 3 and antenna 4.According to current discussion result, on preceding two RE of mini-CCE, the base station sends information based on SFBC on first and the 3rd antenna; On latter two RE of mini-CCE, the base station sends information based on SFBC on second and the 4th antenna

According to current discussion result, PHICH is mapped to 3 mini-CCE and goes up transmission, that is to say that ACK/NACK bit triplicate also transmits in each mini-CCE respectively.On each mini-CCE, with an extended code ACK/NACK bit is expanded, be mapped to then on 4 RE of mini-CCE.According to current discussion result, to the scene of base station configuration two transmit antennas, the spreading factor of extended code (SF) is 4.Be an example of this mapping ACK/NACK bit as shown in Figure 2, only described the mapping method of ACK/NACK on a mini-CCE here.The length of expansion code word is 4, and the expansion code word of 4 quadratures can be arranged like this, and for example, length is 4 walsh codes of 4.As shown in Figure 2, the expansion code word of remembering certain ACK/NACK channel is w ₀, w ₀=[w ₀₀, w ₀₁, w ₀₂, w ₀₃].To the ACK/NACK bit of input, the extended operation among Fig. 2 is actually mould 2 and adds computing.The ACK/NACK bit is 4 expansion code word w through length ₀Expansion is mapped to each element respectively on the RE of mini-CCE inside then.

Problem below the method for this mapping ACK/NACK bit exists.Because the ACK/NACK bit is being to be mapped on 4 RE of mini-CCE to transmit after the expansion, this frequency domain response that just requires wireless channel on these 4 RE constant or change little, thereby keep orthogonality between the expansion code word as far as possible.When the time delay ratio of wireless channel is big, its coherence bandwidth is less, and its frequency domain response changes very fast, and the frequency domain response on 4 RE in the mini-CCE changes greatly, thereby destroyed the orthogonality between the expansion code word to a certain extent, influenced ACK/NACK multiplexing of channel performance.In addition, when base station configuration 4 antenna transmit diversities, according to present discussion result, 4 antenna transmit diversity technology adopt SFBC+FSTD.At this moment, on preceding two RE of mini-CCE, the base station sends preceding two elements of the ACK/NACK bit after expanding based on SFBC at antenna 1 and antenna 3; Simultaneously, on latter two RE of mini-CCE, the base station sends latter two element of the ACK/NACK bit after expanding based on SFBC at antenna 2 and antenna 4.It should be noted that antenna (1,3) channel is to be independent of antenna (2,4) channel, promptly preceding 2 elements and back 2 elements of the ACK/NACK bit after the expansion are to send on separate channel, thus the orthogonality of expansion code word is suffered serious destruction.

According to the discussion result of current LTE, to non-persistent scheduling (persistent scheduling), the HARQ ACK/NACK channel of a subscriber equipment is impliedly to determine by the index of PDCCH.Simultaneously since PDCCH obtain by making up one or more CCE, so HARQ ACK/NACK channel impliedly determined in the index of the CCE that can take by PDCCH.When PDCCH only is made up of a CCE, determine its ACK/NACK channel according to the index of this CCE; When PDCCH is when obtaining by a plurality of CCE of cascade, can be according to the index of one of them CCE, for example the index of first CCE comes the implicit ACK/NACK channel of determining its correspondence.

According to the discussion result of LTE, when the two transmitting antenna of base station configuration, SF equals 4, promptly at multiplexing 4 the ACK/NACK channels of mini-CCE, so the mapping method of 4 CCE to 4 ACK/NACK channels of same mini-CCE is discussed here.As shown in Figure 3, a kind of method is that 4 CCE are mapped to 4 walsh codes in the walsh matrix successively.When PDCCH was made up of a CCE, the index of CCE was exactly the index of walsh code in walsh matrix; When PDCCH was made up of two CCE, the index of first CCE of each PDCCH was exactly the index of walsh code in walsh matrix, and the index of promptly available walsh code is 0 and 2, and index is that 1 and 3 walsh code is disabled; When PDCCH was made up of four CCE, the index of first CCE of PDCCH was exactly the index of walsh code in walsh matrix, and promptly having only index is that 0 walsh code can be used, and the walsh code of other 3 index (1～3) is all unavailable.

Problem below the method for this mapping CCE and walsh code exists.When base station configuration two PDCCH, and these two PDCCH are when being combined by two CCE, it is 0 and 2 walsh code that the ACK/NACK channel of these two subscriber equipmenies makes index of reference respectively.But index is that 0 and 2 walsh code is relatively more responsive to the variation of the frequency domain response of channel, and promptly when the frequency response change of 4 RE of mini-CCE, index is that the cross-correlation decoding performance of 0 and 2 walsh code worsens comparatively fast.

According in the current LTE system to the discussion result of descending distributed channel, each distributed channel is mapped on each a part of resource of Nd Physical Resource Block (PRB), and Nd equals 2 or 3.When mainly Nd=2 being discussed here, distributed channel is mapped to the collocation method of two PRB.According to current discussion result, a kind of method is to make distributed channel take first time slot among a PRB therein, takies second time slot in another PRB.That is to say that distributed channel is to obtain by timeslot-based frequency hopping, promptly on the border of time slot from another PRB of a PRB conversion.Be the schematic diagram of the distributed channel that disposes in this way as shown in Figure 4.

Problem below this method exists.According to the discussion result of current LTE, Physical Downlink Control Channel (PDCCH) is transmission in the individual OFDM symbol of the preceding n (smaller or equal to 3) of subframe, promptly transmits in preceding n OFDM symbol of first time slot of subframe.Remember the M that adds up to of OFDM symbol in the time slot, the number of the OFDM symbol that can be used for transfer of data of first time slot in the subframe is M-n, and all M OFDM symbols of second time slot in the subframe may be used to transfer of data.Like this, the OFDM symbol numbers that is used for transfer of data of first time slot is lacked n than second time slot.As shown in Figure 4, example one, example two and example three are respectively the configuration schematic diagram of distributed channel when n equals 1,2 and 3.This distributed transmission channel based on the boundary of time slot frequency hopping is to transmit in two frequency bands that keep at a certain distance away though guaranteed downlink data, and the physical resource number is unequal in two frequency bands.Obviously when the physical resource number two frequency bands in was equal, the distributed transmission channel had the performance of the best, so can descend based on the performance of the distributed transmission channel of boundary of time slot frequency hopping.

Summary of the invention

The purpose of this invention is to provide a kind of method that in wireless communication system, disposes hybrid automatic repeat request indication channel.

According to an aspect of of the present present invention, a kind of mapping ACK/nack message comprises the steps: to the method for mini-CCE

A) base station is that 4 extended code is expanded the ACK/NACK bit with length;

B) base station is mapped to the I/Q branch road of preceding 2 RE of mini-CCE to the code word after expanding, and carries out the QPSK modulation, and repeats this operation on back 2 RE of mini-CCE;

C) the transmit diversity coding is carried out to the modulation symbol of mini-CCE in the base station;

D) base station sends ack/nack signal.

According to another aspect of the present invention, a kind of mapping CCE comprises the steps: to the method for ACK/NACK extended code

A) base station obtains Physical Downlink Control Channel with one or more CCE combination;

B) base station configuration is determined the mapping relations of index of the extended code of ACK/NACK channel from the index of CCE, guarantees the their cross correlation optimization of the extended code used simultaneously;

C) base station sends ack/nack signal.

According to another aspect of the present invention, a kind of method of configuring distributed channel comprises the steps:

A) base station sends control signaling in preceding n OFDM symbol of subframe;

B) the frequency hopping transfer point of base station configuration distributed channel makes the number of the OFDM symbol of distributed channel in two PRB equal substantially;

C) base station sends downlink data on distributed channel.

Description of drawings

Fig. 1 is the downlink frame structure of LTE Class1;

Fig. 2 is the method for expansion and mapping ACK/NACK bit;

Fig. 3 is the mapping method that CCE indexes the ACK/NACK code word;

Fig. 4 is based on the distributed channel collocation method of time slot frequency hopping;

Fig. 5 is the method for expansion of the present invention and mapping ACK/NACK bit;

Fig. 6 is the schematic diagram of the embodiment of the invention 1;

Fig. 7 is the schematic diagram of the embodiment of the invention 2;

Fig. 8 is the schematic diagram of the embodiment of the invention 3.

Embodiment

The problem that exists in the existing method at last surface analysis, the present invention has correspondingly proposed solution, specifically describes as follows:

Mapping ACK/nack message is to the method for mini-CCE

In order to obtain frequency diversity gain, ACK/NACK information is to be mapped to M mini-CCE to go up transmission, the discussion result current according to LTE, and M equals 3.Following emphasis is described in the method for mapping ACK in the mini-CCE/NACK bit, and this method is equally applicable to other mini-CCE of ACK/NACK bit mapping.

For the variation of the frequency response that reduces wireless channel influence, need be mapped to the ACK/NACK extended code on the least possible RE the orthogonality of the extended code of ACK/NACK.The SF that considers extended code is 4, and promptly its length is 4, supposes each RE among the mini-CCE is adopted the QPSK modulation, and promptly each RE can carry I/Q two-way information.Like this, can be length on the road of 4 the extended code I/Q that is mapped to two RE.Specifically, ACK/NACK bit length is the expansion of 4 extended code after, be mapped on preceding two RE of mini-CCE, the code word after the expansion is mapped on latter two RE of mini-CCE repeats to send simultaneously.Note, can the code word after the expansion be mapped directly on latter two RE of mini-CCE here, also can be to being mapped to again on latter two RE of mini-CCE after the code word negate after the expansion.Be the schematic diagram of this method as shown in Figure 5.Here, note length is that 4 extended code is w, w=[w ₀, w ₁, w ₂, w ₃], a kind of possible extended code is a walsh code.The ACK/NACK bit is after extended code w expansion, and preceding two element map are to first RE of mini-CCE, and latter two element map is to second RE of mini-CCE.Equally, on the 3rd of mini-CCE and the 4th RE, repeat above-mentioned mapping process.Adopt this mapping method, when receiving terminal carries out despreading according to extended code, de-spreading operation is actually on two RE in mini-CCE and carries out, i.e. despreading and despreading on latter two RE on preceding two RE, the performance that its anti-frequency domain response changes is better than existing method shown in Figure 2 is finished despreading on 4 RE of mini-CCE performance.Note, when considering adjacent area interference, because preceding two RE of mini-CCE and latter two RE repeat to send ACK/NACK information, so realized on 4 RE of mini-CCE on average to what disturb, the present invention equates with the adjacent area interference average behavior of existing method shown in Figure 2.

When the base station configuration double antenna, according to above-mentioned method the ACK/NACK bit after expanding is mapped to mini-CCE, be after ACK/NACK bit length is the expansion of 4 extended code, be mapped to respectively on preceding two RE and latter two RE of mini-CCE, on preceding two RE of mini-CCE and latter two RE, carry out the SFBC coding then respectively, the information of the ACK/NACK code word after then in each SFBC encoding block, all having comprised complete expansion.

Top method can expand to the scene of base station configuration four antennas simply, according to above-mentioned method the ACK/NACK bit after expanding is mapped to mini-CCE, be after ACK/NACK bit length is the expansion of 4 extended code, be mapped to respectively on preceding two RE and latter two RE of mini-CCE, on 4 RE of mini-CCE, carry out the SFBC+FSTD coding then.Specifically, signal on preceding two RE of mini-CCE is carried out SFBC coding and is mapped on two transmit antennas (for example antenna 1 and antenna 3), simultaneously the signal on latter two RE of mini-CCE is carried out the SFBC coding and be mapped on other two transmit antennas (for example antenna 2 and antenna 4).An encoder matrix that is SFBC+FSTD is $\left[\begin{array}{cccc}{s}_1& {\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A200710149990E00171.png,A200710149990E00172.png"\; state="\{\{state\}\}">s</figure-callout>}}_2& 0& 0\\ 0& 0& s_3& s_4\\ -{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A200710149990E00171.png,A200710149990E00172.png"\; state="\{\{state\}\}">s</figure-callout>}}_2^{*}& s_1^{*}& 0& 0\\ 0& 0& -s_4^{*}& s_3^{*}\end{array}\right].$ Here, the information that has all comprised the ACK/NACK code word after the complete expansion in each SFBC encoding block.Adopt this mapping method, when receiving terminal carries out despreading, de-spreading operation is actually despreading and soft merging respectively on preceding two RE in mini-CCE and latter two RE, thereby guarantees that orthogonality is not destroyed between the extended code, has solved the problem that method shown in Figure 2 exists when four antennas.

For the problem that the existing method that solves Fig. 2 exists when base station configuration 4 transmit antennas, another kind of method is the method that keeps expansion ACK/NACK bit shown in Figure 2 and be mapped to 4 RE of mini-CCE.But do not re-use the transmit diversity techniques of SFBC+FSTD.At this moment can adopt the technology based on SFBC+CDD, CDD is a Cyclic Delay Diversity here.First method is on two RE in mini-CCE, encoder matrix C (the r)=A+e of configuration transmit diversity ^{J θ (r)}B, here $A=\left[\begin{array}{cc}{s}_1& s_2\\ -{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A200710149990E00171.png,A200710149990E00172.png"\; state="\{\{state\}\}">s</figure-callout>}}_2^{*}& {\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="A200710149990E00172.png"\; state="\{\{state\}\}">s</figure-callout>}}_1^{*}\\ 0& 0\\ 0& 0\end{array}\right],$ $B=\left[\begin{array}{cc}0& 0\\ 0& 0\\ s_1& s_2\\ -{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A200710149990E00171.png,A200710149990E00172.png"\; state="\{\{state\}\}">s</figure-callout>}}_2^{*}& {\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="A200710149990E00172.png"\; state="\{\{state\}\}">s</figure-callout>}}_1^{*}\end{array}\right],$ R=0,1,2 ... 2M-1, here ,-2 π＜θ (r)＜2 π is phase deviation.M is the number of the mini-CCE that is mapped to of ACK/NACK bit, because top encoder matrix is the diversity signal of handling on 2 RE, so r can have 2M value at most.Second method is on 4 RE in mini-CCE, the encoder matrix of configuration transmit diversity

C (r)=A+e ^{J θ (r)}B, here $A=\left[\begin{array}{cccc}{s}_1& {\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A200710149990E00171.png,A200710149990E00172.png"\; state="\{\{state\}\}">s</figure-callout>}}_2& 0& 0\\ -{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A200710149990E00171.png,A200710149990E00172.png"\; state="\{\{state\}\}">s</figure-callout>}}_2^{*}& {\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="A200710149990E00172.png"\; state="\{\{state\}\}">s</figure-callout>}}_1^{*}& 0& 0\\ 0& 0& s_3& s_4\\ 0& 0& -s_4^{*}& s_3^{*}\end{array}\right].$ $B=\left[\begin{array}{cccc}0& 0& s_3& s_4\\ 0& 0& -s_4^{*}& s_3^{*}\\ s_1& s_2& 0& 0\\ -{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A200710149990E00171.png,A200710149990E00172.png"\; state="\{\{state\}\}">s</figure-callout>}}_2^{*}& s_1^{*}& 0& 0\end{array}\right],$

R=0,1,2 ... M-1, here ,-2 π＜θ (r)＜2 π is phase deviation.M is the number of the mini-CCE that is mapped to of ACK/NACK bit.In the above-mentioned formula, the signal of the corresponding transmit antennas of each row of matrix, the signal of the corresponding RE of each row of matrix.

Mapping CCE is to the method for ACK/NACK extended code

The number of remembering the ACK/NACK channel of each mini-CCE configuration is N, and in LTE, each mini-CCE comprises 4 RE, when adopting the multiplexing mode of I/Q, at most can multiplexing 8 ACK/NACK channels, and promptly N equals 8.According to current discussion result, when the base station configuration double antenna, SF equals 4, promptly maximum multiplexing 4 ACK/NACK channels simultaneously, and N equals 4 like this.According to the result of current LTE, PDCCH obtains by making up one or more CCE, to non-persistent scheduling, is that HARQ ACK/NACK channel impliedly determined in the index of the CCE that takies by PDCCH.The ACK/NACK channel is to carry out code division multiplexing with extended code in a mini-CCE, and promptly the index of CCE is mapped to the index of extended code one by one, and a kind of possible extended code is a walsh code.

In order to guarantee that the ACK/NACK channel has best performance, need guarantee the their cross correlation optimization of the extended code that ACK/NACK channel that the base station sends simultaneously is used in same mini-CCE as far as possible.With the walsh code is example, according to top analysis, directly according to the order of the code word in the walsh matrix walsh code being carried out index and shines upon with CCE is not a kind of method of optimum, because in some cases, only some walsh code is used, and the their cross correlation of these walsh codes when frequency domain response changes is bad.So the present invention proposes to adjust the order of walsh code, thereby guarantee that as far as possible those walsh codes that use simultaneously have good their cross correlation.

The method of configuring distributed channel

Comprise N OFDM symbol in the note subframe, according to the discussion result of LTE, preceding n OFDM symbol of a subframe is to be used for transmitting control channel, and the maximum of note n is n _MaxThe method of the configuring distributed channel when Nd equals 2 is discussed below the present invention.These methods are by obtain the improvement of the method for distributed channel in the boundary of time slot frequency hopping to existing.Here the number of remembering the OFDM symbol in the subframe is N.

First method is the number n according to the OFDM symbol of a subframe inner control channel occupancy, determines the frequency hopping transfer point of distributed channel, thereby the number of the OFDM symbol of assurance distributed channel in two PRB equates or differs one.Specifically, the frequency hopping transfer point of note distributed channel is between the k of subframe and k+1 OFDM symbol, then

Perhaps

Adopt this method, the number n of the OFDM symbol that control channel takies is indicated in the base station in PCFICH, and correspondingly indicates the frequency hopping transfer point of distributed channel.

Second method is the mean value n according to the number n of the OFDM symbol of subframe inner control channel occupancy, determines the frequency hopping transfer point of distributed channel.Specifically, the frequency hopping transfer point of note distributed channel is between the k of subframe and k+1 OFDM symbol, then

Perhaps

Adopt this method, the frequency hopping transfer point of distributed channel is a static configuration, does not rely on PCFICH, thereby is not subjected to PCFICH to detect wrong influence, but works as n _MaxWhen bigger, the performance of this method is than first method difference.

Embodiment

This part has provided three embodiment of this invention, and is too tediously long for fear of the description that makes this patent, in the following description, omitted the detailed description of function that the public is known or device etc.

First embodiment

The example of mapping ACK/nack message of the present invention to the method for mini-CCE described in the present embodiment.According to the discussion result of LTE, mini-CCE comprises 4 RE, supposes that here the length of the extended code of ACK/NACK is 4, and promptly SF equals 4.Each RE that supposes mini-CCE adopts the QPSK modulation, and the multiplexing two-way information of the I/Q branch road of RE.

As shown in Figure 6, the expansion code word of supposing certain ACK/NACK channel here is w ₀, note w ₀=[w ₀₀, w ₀₁, w ₀₂, w ₀₃].And the ACK/NACK bit of supposing current transmission is 0, and it is identical with code word and extended code after extended code type matrix 2 adds computing, then this code word is mapped on the RE of mini-CCE.As shown in Figure 6, mould 2 adds preceding two element w of the code word after the computing ₀₀And w ₀₁Be mapped on first RE of mini-CCE, and carry out QPSK modulation and obtain (1-2w ₀₀)+j (1-2w ₀₁); Mould 2 adds latter two element w of the code word after the computing ₀₂And w ₀₃Be mapped on second RE of mini-CCE, and carry out QPSK modulation and obtain (1-2w ₀₂)+j (1-2w ₀₃), note the QPSK symbol not being carried out normalization here.On latter two RE of mini-CCE, repeat above-mentioned mapping and QPSK modulated process then.

As shown in Figure 6, example one is used to illustrate the situation of base station configuration double antenna, promptly the modulation symbol on preceding two RE of mini-CCE is carried out SFBC coding and sends on two antennas; Equally the modulation symbol on latter two RE of mini-CCE is carried out the SFBC coding and on two antennas, send.Example two is used to illustrate the situation of base station configuration four antennas, and adopts the transmit diversity techniques of SFBC+FSTD, promptly the modulation symbol on preceding two RE of mini-CCE is carried out SFBC coding and transmission on antenna 1 and antenna 3; Simultaneously, the modulation symbol on latter two RE of mini-CCE is carried out SFBC coding and transmission on antenna 2 and antenna 4.

Second embodiment

The example of mapping CCE of the present invention to the method for ACK/NACK extended code described in the present embodiment.With LTE Class1 system is example, supposes multiplexing 4 ACK/NACK channels on a mini-CCE here, and employing length is 4 walsh code.

According to the analysis among Fig. 3, when base station configuration two PDCCH, and these two PDCCH are when being combined by two CCE, it is 0 and 2 walsh code that the ACK/NACK channel of these two subscriber equipmenies makes index of reference.But index is that 0 and 2 walsh code is relatively more responsive to the variation of the frequency domain response of channel.Be solution of the present invention as shown in Figure 7.Variation in order to contrast with Fig. 3, supposes that walsh code still carries out index according to its position in walsh matrix from the mapping relations that CCE indexes walsh code.To the method for Fig. 3, the index that CCE is mapped to walsh code equates with the index of CCE.In the method for Fig. 7, index is that the index of the walsh code of 0 CCE mapping is 0; Index is that the index of the walsh code of 1 CCE mapping is 1; Index is that the index of the walsh code of 2 CCE mapping is 3; Index is that the index of the walsh code of 3 CCE mapping is 2.Adopt the method for Fig. 7, when base station configuration two PDCCH, and these two PDCCH are when being combined by two CCE, it is 0 and 3 walsh code that the ACK/NACK channel of these two subscriber equipmenies makes index of reference, and these two walsh codes have their cross correlation preferably when frequency response change.

The 3rd embodiment

An example of the method for configuring distributed channel of the present invention is described in the present embodiment.With LTE Class1 system is example, and according to the discussion result of current LTE, the number n that first time slot of subframe is used for the OFDM symbol of transmitting control channel is 1,2 or 3.

As shown in Figure 8, the method for configuring distributed transmission channel is between first OFDM symbol and second OFDM symbol of configuration frequency hopping transfer point second time slot being fixed in subframe.Specifically, the distributed data channel takies back N-n OFDM symbol of first time slot and first OFDM symbol of second time slot in a PRB; And in another PRB, take back N-1 OFDM symbol of second time slot.As shown in Figure 8, example one is the configuration schematic diagram of distributed channel when n equals 1, and the OFDM symbol numbers of distributed channel in first PRB Duoed one than second PRB; Example two is configuration schematic diagram of distributed channel when n equals 2, and the OFDM symbol numbers of distributed channel in first PRB equates with second PRB; Example three is configuration schematic diagram of distributed channel when n equals 3, and the OFDM symbol numbers of distributed channel in first PRB lacked one than second PRB.

Claims (9)

1. a mapping ACK/nack message comprises step to the method for mini-CCE:

A) base station is that 4 extended code is expanded the ACK/NACK bit with length;

B) base station is mapped to the I/Q branch road of preceding 2 RE of mini-CCE to the code word after expanding, and carries out the QPSK modulation, and repeats this operation on back 2 RE of mini-CCE;

C) the transmit diversity coding is carried out to the modulation symbol of mini-CCE in the base station;

D) base station sends ack/nack signal.

2. method according to claim 1 is characterized in that in step c), and to the code word that the ACK/NACK bit obtains through the extended code expansion, preceding two element map are to first RE of mini-CCE, and latter two element map is to second RE of mini-CCE.

3. method according to claim 1 is characterized in that in step c), carries out the SFBC coding on preceding two RE of mini-CCE and latter two RE respectively.

4. method according to claim 1, it is characterized in that in step c), signal on preceding two RE of mini-CCE is carried out SFBC coding and is mapped on two transmit antennas, simultaneously the signal on latter two RE of mini-CCE is carried out the SFBC coding and be mapped on other two transmit antennas.

5. a mapping CCE comprises the steps: to the method for ACK/NACK extended code

A) base station obtains Physical Downlink Control Channel with one or more CCE combination;

B) base station configuration is determined the mapping relations of index of the extended code of ACK/NACK channel from the index of CCE, guarantees the their cross correlation optimization of the extended code used simultaneously;

C) base station sends ack/nack signal.

6. method according to claim 5 is characterized in that in step b), and index is that the index of the walsh code of 0 CCE mapping is 0; Index is that the index of the walsh code of 1 CCE mapping is 1; Index is that the index of the walsh code of 2 CCE mapping is 3; Index is that the index of the walsh code of 3 CCE mapping is 2.

7. the method for a configuring distributed channel comprises the steps:

A) base station sends control signaling in preceding n OFDM symbol of subframe;

B) the frequency hopping transfer point of base station configuration distributed channel makes the number of the OFDM symbol of distributed channel in two PRB equal substantially;

C) base station sends downlink data on distributed channel.

8. method according to claim 8 is characterized in that in step b), and the frequency hopping transfer point of note distributed channel is between the k of subframe and k+1 OFDM symbol, then

Perhaps

Here n is the number of the OFDM symbol that is used for control channel of current subframe, and N is the sum of the OFDM symbol in the subframe.

9. method according to claim 8 is characterized in that in step b), and the frequency hopping transfer point of note distributed channel is between the k of subframe and k+1 OFDM symbol, then

Perhaps

Here n is the mean value of number n of the OFDM symbol of subframe inner control channel occupancy, and N is the sum of the OFDM symbol in the subframe.

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