CN101588631B - Method for controlling channel resource allocation - Google Patents

Abstract

The invention provides a method for controlling channel resource allocation, comprising the following steps: usable physical resources of physical control channels are grouped, wherein each group of usable physical resources is used as a minimum unit of physically controlled channel allocation and called as a physical resource group; a physical number is allocated for each physical resource group,and the physical resource group are physically numbered according to frequency sequence thereof; the physical resource groups are logically allocated to the physical control channels, wherein each ph ysical control channel comprises a plurality of logical physical resource groups; the logical physical resource groups are logically numbered, wherein the physical resource groups of the physical control channels with the same type are serially numbered; the logical numbers are mapped by a bit turnover method, wherein a value obtained by mapping is a physical number of the physical resource group corresponding to the logical number; and the physical resource group corresponding to the physical number obtained by mapping is allocated to the physical control channel.

Description

Control channel resource allocation method

Technical Field

The invention relates to a control channel resource allocation method of an LTE (Long Term Evolution) system.

Background

In the 3GPP (third generation partnership project) LTE project, OFDM (Orthogonal Frequency Division Multiplexing) technology is adopted for uplink and downlink radio channels, and a grid-like distribution is adopted for allocation of physical resources of the uplink and downlink channels, as shown in fig. 1.

In fig. 1, each small square represents a minimum Resource Element (RE) of Resource allocation, and the downlink Physical control channels share a Physical Broadcast Channel (PBCH), a Physical Control Format Indicator Channel (PCFICH), a Physical HARQ Indicator Channel (PHICH), and a Physical Downlink Control Channel (PDCCH) according to the existing 3GPP protocol definition, where the PBCH protocol has a Resource allocation manner that is clearly defined and does not belong to the discussion of the method. And then, the protocol defines that the physical resource distribution of the three physical Control channels must be continuously distributed every 4 REs, so that the minimum unit of physical resource allocation of PCFICHPHICH and PDCCH is 4 continuous REs, which is referred to as miniCCE (Control Channel Element) herein.

One of the biggest advantages of the OFDM technology in LTE is the frequency diversity immunity, so that the control channels in the same cell are kept at a relatively large distribution distance in the frequency domain as much as possible, which is the first problem to be considered in the LTE downlink physical control channel resource allocation.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a method for allocating physical control channel resources to reduce mutual interference of logically adjacent control channels in a frequency domain.

In order to solve the above technical problem, the present invention provides a method for allocating control channel resources, comprising the following steps:

grouping the available physical resources of the physical control channels, wherein each group is the minimum unit allocated to the physical control channels and is called a physical resource group, allocating a physical number to each physical resource group, and performing physical numbering according to the frequency sequence of the physical resource groups;

logically distributing physical resource groups for physical control channels, wherein each physical control channel comprises a plurality of logical physical resource groups and logically numbers the logical physical resource groups, and the logical numbers of the physical resource groups of the physical control channels of the same type are continuous;

mapping the logic number by adopting a bit flipping method, wherein the value obtained by mapping is the physical number of the physical resource group corresponding to the logic number;

and allocating the physical resource group corresponding to the physical number obtained by mapping to the physical control channel.

Furthermore, the method can also have the following characteristics that the physical control channel is a physical hybrid automatic repeat indicator channel PHICH and a physical downlink control channel PDCCH, the logical numbers of the physical resource groups of the PHICH are continuous, and the logical numbers of the physical resource groups of the PDCCH are continuous.

Further, the method may further have a feature that each physical resource group includes four resource elements REs consecutive in the frequency domain.

Further, the method may further include the following step, wherein the available physical resources of the physical control channel are wireless physical resources excluding physical resources occupied by the reference signal and the physical control format indicator channel PCFICH.

Further, the above method may further include the step of, when each physical resource group is physically numbered, starting numbering from the next physical resource group that is consecutive in the frequency domain from the first physical resource group occupied by the PCFICH.

Furthermore, the method can also have the following characteristics that P physical resource groups exist, the physical numbers of the P physical resource groups are 0, 1, 2, 3, the specification, and P-1, M physical resource groups need to be allocated to the PHICH and the PDCCH, the logical numbers of the M physical resource groups are 0, 1, 2, 3, the specification, and M-1, and M is less than or equal to P; mapping the logic number by a bit flipping method to obtain a physical number, which mainly comprises the following steps:

step 10, setting i to 0 and j to 0;

step 20, convert j to binary with a bit number of

The representation is rounded up to obtain a binary number a, the bit number of the a is turned over to obtain a binary number b, and the b is converted into a decimal number Y;

step 30, comparing Y with P, if Y is less than P, increasing the physical number X of the physical resource group with the logic number i to Y, increasing 1 for i, and jumping to step 40, if Y is more than or equal to P, jumping to step 40;

step 40, j is increased by 1, if i < M, go to step 20, otherwise, end.

The method of the invention can ensure that the frequency domains of the logically adjacent control channels of the same type keep as large a distance as possible in the same cell so as to reduce the interference among each other and increase the diversity effect of the OFDM technology.

Drawings

Fig. 1 is a schematic diagram of a grid-shaped distribution of time/frequency physical channel resources of an LTE system;

FIG. 2 is a flow chart of a method for allocating physical control channel resources according to the present invention;

FIG. 3 is a flow chart of the resource mapping bit flipping method of the present invention;

fig. 4 is a schematic diagram of the maximum/minimum/average distances of the logically adjacent miniCCE physical frequency domains.

Detailed Description

The invention provides a method for allocating downlink physical control channel resources, which comprises the steps of carrying out logic numbering and physical numbering on physical channels and mapping corresponding logic numbering to physical numbering by adopting a bit flipping method, so that the interference among the logic numbering and the physical numbering is minimum.

The method of the invention is shown in figure 2 and mainly comprises the following steps:

step 10, dividing the RE without RS (Reference Signal) in the radio physical resource into a group of 4 REs, where each group of 4 REs is a continuous RE in each frequency domain, that is, a miniCCE or a minimum unit allocated by a physical control channel, and a miniCCE is referred to as a physical resource group;

step 20, firstly, according to the protocol specification, allocating PCFICH frequency resources, removing miniCCE occupied by PCFICH, and reserving miniCCE for the rest, namely available physical resources which can be allocated to PHICH and PDCCH;

step 30, performing physical numbering for the reserved miniCCE, wherein the initial miniCCE (numbered 0) is the next miniCCE (4 continuous REs in the frequency domain) which is occupied by the PCFICH and is continuous in the frequency domain, and the physical numbering is 0, 1, 2, 3,. Carrying out physical numbering according to the frequency sequence of a physical resource group (miniCCE), wherein the sequence of the physical numbering is consistent with or opposite to the frequency sequence of the miniCCE; that is, the greater the frequency, the greater the number, or the greater the frequency, the smaller the number.

Step 40, logically distributing physical resource groups for physical control channels, wherein each physical control channel comprises a plurality of logical physical resource groups and logically numbers the logical resource groups, and the logical numbers of the physical resource groups of the physical control channels of the same type are continuous;

because the priority of the PHICH is higher than that of the PDCCH, the logical number of miniCCE is obtained by adopting the allocation sequence of the PHICH and the PDCCH, and if the PHICH needs to occupy N miniCCEs in total and the PDCCH needs to occupy M miniCCEs in total, the logical number of the miniCCEs is 0, 1, 2, 1, N-1, N, N +1, N + M-1, wherein N + M is less than or equal to P;

step 50, mapping the logic number by adopting a bit flipping method, wherein the mapped value is the physical number of the physical resource group corresponding to the logic number;

mapping the logic miniCCE number into a physical miniCCE number by adopting a BRI (Bit-reverse Interleaver) mapping method, wherein the maximum Bit number is related to the maximum miniCCE supported by the system when BRI mapping is carried out, and if P is the maximum miniCCE number contained in the physical resource, the required Bit number in BRI is the number of the miniCCE

Wherein,

represents rounding up;

fig. 3 shows a BRI mapping method, which specifically includes the following steps:

step 501, setting up

Step 502, setting i to 0, identifying the logic number of miniCCE, and setting j to 0;

step 503, converting j into a binary system, where the bit number is n, to obtain a binary number a, and this process is identified by an equation a ═ dec2bin (j, n);

step 504, the bit number of the binary number a is inverted to obtain a binary number b, that is, if a is 0010, the first 0 is put to the last, the second 0 is put to the second last, the third 1 is put to the second, and the fourth 0 is put to the first, then the inverted b is 0100, and the process is identified by equation b which is fliplr (a);

step 505, converting b into a decimal number, which is expressed by an equation of Y ═ bin2dec (b);

step 506, if Y is smaller than P, go to step 507, otherwise, go to step 508;

step 507, obtaining the physical number X of the physical resource with the logical number i as Y, and i as i +1, and jumping to step 508;

step 508, setting j ═ j + 1;

in step 509, if i is smaller than M, go to step 503, otherwise, the process ends.

And step 60, after mapping to obtain the physical numbers of the physical resource groups of each logic number, correspondingly allocating the physical resource groups corresponding to the physical numbers to the PHICH and the PDCCH.

That is, the physical resource group corresponding to the physical number mapped by the logical number is allocated to the physical control channel to which the logical number belongs in step 40.

Fig. 4 is a diagram illustrating maximum distances, minimum distances and average distances of frequency domain mapping when P varies from 8 to 50. The abscissa is the number of miniCCEs, the ordinate is the distance between the physical frequency domains of logically adjacent miniCCEs, and the distance is represented by the distance of physical numbers in the figure. And the logically adjacent control channels are the same control channel, thereby ensuring that the frequencies of the logically adjacent control channels of the same type are staggered as much as possible.

In summary, the method can ensure that the frequency domains of logically adjacent control channels of the same type are kept as far as possible in the same cell, so as to reduce the interference between each other and increase the diversity effect of the OFDM technology.

Claims (6)

1. A method for allocating control channel resources, comprising the steps of:

grouping the available physical resources of the physical control channels, wherein each group is the minimum unit allocated to the physical control channels and is called a physical resource group, allocating a physical number to each physical resource group, and performing physical numbering according to the frequency sequence of the physical resource groups;

logically distributing physical resource groups for physical control channels, wherein each physical control channel comprises a plurality of logical physical resource groups and logically numbers the logical physical resource groups, and the logical numbers of the physical resource groups of the physical control channels of the same type are continuous;

mapping the logic number by adopting a bit flipping method, wherein the value obtained by mapping is the physical number of the physical resource group corresponding to the logic number;

and allocating the physical resource group corresponding to the physical number obtained by mapping to the physical control channel.

2. The method of claim 1, wherein the physical control channels are a physical hybrid automatic repeat indicator channel (PHICH) and a Physical Downlink Control Channel (PDCCH), and wherein logical numbers of physical resource groups of the PHICH are consecutive and logical numbers of physical resource groups of the PDCCH are consecutive.

3. The method of claim 1, wherein each set of physical resources comprises four Resource Elements (REs) that are contiguous in a frequency domain.

4. The method of claim 1, 2 or 3, wherein the available physical resources of the physical control channel are wireless physical resources excluding physical resources occupied by a reference signal and a Physical Control Format Indicator Channel (PCFICH).

5. The method according to claim 1, 2 or 3, wherein when each physical resource group is physically numbered, the numbering is performed from the next physical resource group which is contiguous in the frequency domain to the first physical resource group occupied by the PCFICH.

6. The method of claim 1 or 2 or 3, wherein there are P groups of physical resources, whose physical number is 0, 1, 2, 3.., P-1, M groups of physical resources need to be allocated to PHICH and PDCCH, whose logical number is 0, 1, 2, 3.., M-1, M is less than or equal to P; mapping the logic number by a bit flipping method to obtain a physical number, which mainly comprises the following steps:

step 10, setting i to 0 and j to 0;

step 20, convert j to binary with a bit number of

The representation is rounded up to obtain a binary number a, the bit number of the a is turned over to obtain a binary number b, and the b is converted into a decimal number Y;

step 30, comparing Y with P, if Y is less than P, increasing the physical number X of the physical resource group with the logic number i to Y, increasing 1 for i, and jumping to step 40, if Y is more than or equal to P, jumping to step 40;

step 40, j is increased by 1, if i < M, go to step 20, otherwise, end.

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