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WO2015096653A1 - 一种无线资源复用方法、基站设备、终端设备和无线通信系统 - Google Patents

一种无线资源复用方法、基站设备、终端设备和无线通信系统 Download PDF

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WO2015096653A1
WO2015096653A1 PCT/CN2014/094153 CN2014094153W WO2015096653A1 WO 2015096653 A1 WO2015096653 A1 WO 2015096653A1 CN 2014094153 W CN2014094153 W CN 2014094153W WO 2015096653 A1 WO2015096653 A1 WO 2015096653A1
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sub
resource
terminal
rsrp
resource group
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French (fr)
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杨学志
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Priority to US15/108,638 priority Critical patent/US10425822B2/en
Priority to EP14874120.0A priority patent/EP3091802B1/en
Priority to KR1020167020831A priority patent/KR102242515B1/ko
Publication of WO2015096653A1 publication Critical patent/WO2015096653A1/zh
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/02—Resource partitioning among network components, e.g. reuse partitioning
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/02—Arrangements for optimising operational condition
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/10—Scheduling measurement reports ; Arrangements for measurement reports
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. Transmission Power Control [TPC] or power classes
    • H04W52/04—Transmission power control [TPC]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. Transmission Power Control [TPC] or power classes
    • H04W52/04—Transmission power control [TPC]
    • H04W52/18—TPC being performed according to specific parameters
    • H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
    • H04W52/243—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters taking into account interferences
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H04W72/044—Wireless resource allocation based on the type of the allocated resource
    • H04W72/0446—Resources in time domain, e.g. slots or frames
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H04W72/044—Wireless resource allocation based on the type of the allocated resource
    • H04W72/0453—Resources in frequency domain, e.g. a carrier in FDMA
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/08—Access point devices
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/02—Resource partitioning among network components, e.g. reuse partitioning
    • H04W16/10—Dynamic resource partitioning
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/02—Resource partitioning among network components, e.g. reuse partitioning
    • H04W16/12—Fixed resource partitioning
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/30—Special cell shapes, e.g. doughnuts or ring cells
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/32—Hierarchical cell structures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present invention belongs to the field of wireless communications, and in particular, to a radio resource multiplexing method, a base station device, a terminal device, and a wireless communication system.
  • the LTE standard proposed the requirement to increase the cell edge rate at the beginning of the development.
  • the industry has proposed a variety of solutions, among which the more famous ones are soft frequency multiplexing and fractional frequency multiplexing.
  • these technologies have been widely studied and applied, and have developed into the key technical feature of LTE "inter-cell interference coordination", that is, ICIC (Inter cell interference coordination).
  • the spectrum used is divided into two parts, each using a different multiplexing factor.
  • the curve in Figure 1 represents the upper limit of the transmitter's transmit power density, and the transmitter's power density can be less than or equal to this upper limit, and cannot exceed this upper limit. This curve is also called Power Density Mask (PDM).
  • PDM Power Density Mask
  • the B1 part with the reuse factor is 3, the upper limit of the transmit power density of the used frequency band is relatively high, and can cover the whole cell; and the B2+B3 part with the reuse factor of 1 has a lower upper limit of the transmit power density and covers only the inner area of the cell.
  • the coverage of fractional frequency reuse is shown in Figure 2 and Figure 3.
  • Figure 2 shows the case of an omnidirectional cell, while Figure 3 shows the case of three sectors, both of which are similar.
  • an omnidirectional cell and a sector are collectively referred to as a cell.
  • the band symbols in Figures 2 and 3, namely B11, B12, B13, B2, B3, are placed inside the farthest boundary of their coverage.
  • B2, B3 is placed inside the cell, indicating that it can only cover the interior of the cell.
  • the area, and B11, B12, and B13 are placed at the edge of the cell, indicating that the entire cell can be covered, and of course, the inside of the cell can be covered, but it is not marked inside the cell.
  • Figures 2 and 3 show a regular hexagonal cell, the interior of which is represented as a regular circle or ellipse.
  • the shape of the cell is generally irregular, and the boundary between the interior and the edge of the cell is generally a complicated shape.
  • the interference at the edge of the cell is relatively large, and the interference of the neighboring cell is avoided by the larger multiplexing factor 3, thereby improving the signal-to-noise-and-interference ratio (SINR) of the signal; and the interference within the cell is relatively small, and the multiplexing is performed through a small multiplexing.
  • SINR signal-to-noise-and-interference ratio
  • Factor 1 achieves a relatively high spectral efficiency, so fractional frequency reuse has received attention.
  • Fractional frequency multiplexing is applicable to the uplink (signal from the terminal to the base station) and the downlink (the signal from the base station to the terminal).
  • the soft frequency reuse technique is proposed in the document "Yang Xuezhi, a method for realizing frequency soft multiplexing in wireless communication systems, CN1783861".
  • the power density template is shown in Fig. 4, and Fig. 5 and Fig. 6 show the respective frequency bands. Coverage.
  • the spectrum is divided into three segments, which are denoted as B1, B2, and B3.
  • Each cell selects a frequency band and sets a relatively high power density upper limit, called a primary carrier, which can cover the entire cell.
  • the other frequency bands set a lower power density upper limit, called subcarrier, which can only cover the inner area of the cell.
  • the user at the edge of the cell can only use the primary carrier of the current cell, and the user inside the cell can use the primary carrier or the secondary carrier.
  • B1 is a primary carrier, which has a higher power density upper limit and can cover the entire cell
  • B2 and B3 are subcarriers, and have a lower power density upper limit, and can only cover the internal cell. region.
  • the user at the edge of the cell can only use the primary carrier B1, and the user inside the cell can use either the primary carrier B1 or the secondary carriers B2 and B3.
  • the primary carriers of the neighboring cells do not overlap each other, so the edge users belonging to different neighboring cells do not interfere with each other.
  • the signal to interference and noise ratio is relatively large, which is enough to compensate for the loss in bandwidth, and the communication rate can be greatly improved.
  • the signal of the cell is relatively strong, and the interference of the neighboring cell is relatively small, and all the bandwidths can be utilized, which has high spectral efficiency.
  • Soft frequency reuse overcomes the shortcomings of fractional frequency reuse and has been widely studied and applied. It is currently the mainstream technology in the ICIC field.
  • soft frequency reuse is essentially a network planning technique for each small
  • the resource allocation of the zone provides a constraint framework. Resource allocation within the cell under this constraint framework can achieve better interference modes and improve the performance of the entire network.
  • Soft frequency multiplexing divides communication resources from the frequency dimension, and time parallel to frequency is also a communication resource. If the time is divided into time slices, a different power density upper limit is set on each time slice, which is a soft time multiplexing technique; or more generally, the time-frequency plane is divided into different regions, defined on the time-frequency plane.
  • the power density template forms a soft time-frequency multiplexing technique.
  • the disadvantage of soft frequency multiplexing is that the power density template of each cell has only two levels, which provides a relatively coarse constraint for resource allocation in the cell, and a relatively large performance improvement space.
  • the primary carrier of cell 1 is B1
  • the subcarrier is B2
  • the terminals of cell 1 have two terminals u11 and u12, which communicate with f 1 and f 2 respectively, and f 1 and f 2 belong to B1.
  • U12 is closer to the cell edge than u11 and communicates with greater power.
  • the primary carrier of cell 2 is B2 and the secondary carrier is B1.
  • U21 is closer to the center of the cell than u22, communicating with less power. Both up and down are the same.
  • the interference pattern thus formed is that u11 and u21 interfere with each other, and u12 and u22 interfere with each other.
  • the better interference mode is shown in Figure 8. Because u12 is closer to the edge of the cell than u11, it is more susceptible to interference from the neighboring cell. Therefore, the better mode is to configure u12 to be on the same frequency as u21 with less interference, and u11 to be on the same frequency as u22 with large interference. on. In this case, the user u12 with the worst propagation condition receives the least interference and can obtain a higher rate; and u12 causes the largest interference, and this maximum interference is applied to the user u21 with the best propagation condition. Compared with the interference mode of FIG. 7, the minimum rate of the cell edge is improved, and the highest rate of the cell center is reduced, which can improve the user experience and reduce complaints, which is advantageous for operation.
  • the present invention provides a method, device and system for implementing multi-level soft time-frequency multiplexing and resource allocation in a wireless communication system.
  • the cell is a geographical area, and all time-frequency resources S are used.
  • two different carriers may form two logical cells with different cell identifiers.
  • the two logical cells belong to the same cell.
  • the cell may be an omnidirectional cell or a sector. Adjacent to two cells means that two cells have overlapping coverage areas. Because different power densities are to be set on different time-frequency resources, the wireless communication system is required to be able to divide the time-frequency resource S into several resource units (such as at least two mentioned in the following specific embodiments), each resource unit. It is a time-frequency resource block, which allows the transmission power density to be individually set for each resource unit.
  • the multi-level soft time-frequency multiplexing technical solution according to an embodiment of the present invention:
  • a primary sub-resource group called RG n
  • a power density upper limit l (i) n for another part, a sub-sub-resource group called RG n , the main sub-resource group and the sub-sub-resource group are collectively referred to as sub-resource groups
  • the primary sub-resource groups of the neighboring cells on each resource group do not overlap each other.
  • a primary sub-resource group and a sub-sub-resource combination are referred to as a sub-resource group; a resource group and a sub-resource group on the time-frequency resource S are divided, and an upper limit of the power density of each sub-resource group is called a PDM. information.
  • the cells are also divided into two areas: cell edge and cell center.
  • the cell edge is further divided into two areas, which can be called the most edge and the secondary edge area
  • the cell center is also divided into two areas, which can be called the most Central and sub-central areas.
  • the most edged terminal of a cell allocates the resource with the highest power density upper limit, and this resource has the lowest power density in the neighboring cell and can only be allocated to the most central user. As can be seen from the previous discussion, this is a better interference.
  • the mode avoids the poor interference mode where the most edge and the secondary center interfere with each other, and improves the performance of the system.
  • Multi-level soft time-frequency multiplexing technology can be applied to both uplink and downlink.
  • the base station in the present invention refers to a system device or function that forms and controls a cell, and may be a device node or may be distributed among multiple device nodes.
  • the base station can modify the PDM parameter setting of the local cell according to the situation.
  • the base station broadcasts the PDM information in the cell it forms.
  • the terminal needs PDM information to control the transmit power density of the transmitter, so the base station needs to send the PDM information to the terminal. Since the PDM information can be considered as a configuration parameter of the cell and remains substantially unchanged, it is a better choice to transmit as a system message from the broadcast channel.
  • the PDM determined by the multi-stage soft time-frequency multiplexing technology provides a constraint framework for resource allocation within the cell.
  • a coverage area is determined for all the sub-resource groups (in other words, one coverage area is determined for each sub-resource group), and the upper limit of the power density is set.
  • the child resource group sets a larger coverage.
  • the base station continuously transmits a reference signal with constant power, and the receiving strength of the reference signal of the terminal is recorded as RSRP; and an RSRP threshold is determined for each sub-resource group; A high sub-resource group sets a lower RSRP threshold and sets a higher RSRP threshold for a sub-resource group with a lower power density upper limit.
  • the terminal measures the RSRP and reports it to the base station; for one terminal, sets an RSRP offset for it; the RSRP reported by the terminal uses the offset to correct the RSRP reported by the terminal, and obtains the corrected terminal RSRP.
  • the base station compares the modified terminal RSRP with the RSRP threshold of each sub-resource group, and determines that the sub-resource group whose RSRP threshold is less than or equal to the modified terminal RSRP is to cover the sub-resource group of the terminal, to establish an overlay.
  • a list of sub-resource groups for the terminal That is to say, the corrected terminal RSRP is compared with the RSRP threshold of a sub-resource group.
  • the modified RSRP and all sub-resource groups are The RSRP thresholds are each compared to establish a list of sub-resource groups that cover the terminal.
  • the RSRP offset is a parameter of the terminal, and is reported to the base station when the terminal accesses a cell, and the base station can modify the RSRP offset parameter of the terminal.
  • the base station ranks all the sub-resource groups according to their RSRP threshold size into a sequence; and adds all sub-resource groups whose RSRP thresholds in the sequence is less than or equal to the modified terminal RSRP to the sub-resource group list covering the terminal.
  • the list of child resource groups covering the terminal can be established relatively quickly.
  • the terminal may be mobile, and the list of sub-resource groups covering it may also change. Therefore, the terminal can periodically measure the RSRP and report it to the base station, and the base station updates the sub-resource group list covering the terminal according to the RSRP measurement report of the terminal.
  • the terminal may use a sub-resource group that covers the terminal (ie, a sub-resource group in the sub-resource group list), and does not use a sub-resource group that is not in the sub-resource group list.
  • the user of the present invention refers to a data channel between the application plane terminal and the base station, and may be uplink or downlink, such as one logical channel in the 3GPP Medium Access Control (MAC) protocol.
  • MAC Medium Access Control
  • the invention also discloses a resource allocation method based on multi-level soft time-frequency multiplexing, the steps are: establishing a sub-resource group list covering the terminal for each terminal participating in the resource allocation; for each user who needs to send data, First, allocating resources among sub-resource groups with minimum coverage covering their terminals; if resources are insufficient, allocating resources among sub-resource groups having a second minimum coverage, and so on; if the user obtains the required resources , repeat the process for the next user until all users get the required resources, or there are no resources to allocate.
  • Allocating resources for a user can allocate resources to any of the sub-resource groups that cover its terminal.
  • the terminal at the cell edge will be caused.
  • the user has no resources to allocate, and the small covered sub-resource group is idle. Therefore, resources are allocated to the terminals in the sub-resource group with smaller coverage, so that the resources are effectively utilized, especially when the network load is relatively large.
  • resource allocation information the result of resource allocation is referred to as resource allocation information.
  • a resource allocation method based on multi-stage soft time-frequency multiplexing can be applied to uplink and downlink.
  • the resource allocation information can be directly used to control the transmitter to transmit user data.
  • the resources are allocated at the base station and the transmitter is at the terminal, so the base station transmits the resource allocation information to the terminal, thereby enabling the terminal to transmit the user data on the allocated resources.
  • the resource number refers to the sequence number used to identify a resource when the resource is allocated.
  • the advantage of this is that if a terminal needs to allocate resources on the two primary sub-resource groups, it is convenient to identify the resources. In particular, if the resource numbers of all the primary sub-resource groups are connected together, the continuity of the resource serial numbers of the secondary sub-resource groups is also better, and the identification of the resources is more convenient.
  • the present invention also discloses a base station device, which is called BS0, which implements multi-level soft time-frequency multiplexing in a wireless communication system.
  • BS0 mainly contains the following modules:
  • Transmitting module continuously transmitting a constant power reference signal
  • Receiving module receiving the RSRP and RSRP offsets sent by the terminal, and transmitting the RSRP measurement report corrected by the RSRP offset to the terminal coverage sub-resource group list generation module;
  • N into two parts that do not overlap each other, and a part of which sets a power density upper limit h n , a primary sub-resource group called RG n ;
  • the other part sets the upper limit of power density l n , the secondary resource group called RG n ;
  • the coverage threshold generation module is configured to: determine an RSRP threshold for each sub-resource group; set a lower RSRP threshold for the sub-resource group with a higher power density upper limit, and set a higher RSRP threshold for the sub-resource group with a lower power density upper limit;
  • the RSRP threshold information is sent to the terminal to cover the sub-resource group list generation module.
  • Terminal coverage sub-resource group list generation module for each terminal, according to the terminal
  • the RSRP offset is used to correct the RSRP sent by the terminal, and the modified RSRP is obtained.
  • the modified terminal RSRP is compared with the RSRP threshold of each sub-resource group, and the RSRP threshold is less than or equal to the modified terminal RSRP.
  • the sub-resource group is determined to cover the sub-resource group of the terminal to establish a sub-resource group list covering the terminal. .
  • the base station device BS0 is applied to the downlink (referred to as BS1 for convenience of explanation).
  • BS1 may further include the following modules:
  • a resource allocation module for each user terminal that needs to allocate resources, first allocate resources among sub-resource groups with minimum coverage covering the terminal, and if resources are insufficient, allocate resources among the second smallest-covered sub-resource groups, in turn Analogy; if the terminal obtains the required resources, the process is repeated for the next user until all users who need resources have obtained the required resources, or there are no resources that can be allocated; the resource allocation information is sent to the transmitting module.
  • the foregoing transmitting module is further configured to: allocate resources to the user data according to the resource allocation information, transmit the user data, and perform control so that the transmit power density of the transmitter on each sub-resource group does not exceed the respective sub-resources. The corresponding power density upper limit for each group.
  • the base station device BS0 When the base station device BS0 is applied to the uplink, (referred to as BS2 for convenience of explanation), as shown in FIG. 10, the following modules and functions are further included:
  • a terminal coverage sub-resource group list generation module sending, to a terminal that needs to allocate resources, a sub-resource group list that covers the terminal to the resource allocation module;
  • a resource allocation module for a user terminal that needs to allocate resources, first allocate resources among sub-resource groups with minimum coverage covering the terminal, and if resources are insufficient, allocate resources among the second smallest-covered sub-resource groups, and so on; If the terminal obtains the required resources, the process is repeated for the next terminal until all users who need resources obtain the required resources, or there are no resources that can be allocated; the resource allocation information is sent to the transmitting module;
  • the transmitting module is further configured to: broadcast the PDM information in the cell, and send the resource allocation information determined by the resource allocation module to the terminal.
  • the present invention also discloses a terminal device for implementing multi-level soft time-frequency multiplexing in a wireless communication system, as shown in FIG. 11, which mainly includes the following modules and functions:
  • the receiving module receiving the reference signal transmitted by the base station, sending the signal to the measurement module; receiving the PDM information broadcast by the base station; receiving the resource allocation information; and transmitting the PDM information and the resource allocation information to the transmitting module;
  • a measurement module measuring RSRP and forming an RSRP measurement report, the RSRP measurement report including the measured terminal RSRP, and transmitting to the transmitting module;
  • a transmitting module transmitting an RSRP measurement report and an RSRP offset to the base station; arranging (allocating) resources for the user data according to the resource allocation information, and transmitting the user data; performing control such that the transmitter's transmit power density on each of the sub-resource groups does not exceed The corresponding power density upper limit.
  • the present invention also discloses a wireless communication system for implementing multi-stage soft time-frequency multiplexing, which comprises at least two base station devices (BS0, BS1 or BS2) according to the foregoing technical solution forming two adjacent cells. And the primary sub-resource groups of the two neighboring cells on each resource group do not overlap each other, thereby implementing the multi-stage soft time-frequency multiplexing technology proposed by the present invention.
  • Figure 1 Power density template for fractional frequency reuse.
  • Figure 4 Power density template for soft frequency reuse.
  • Figure 9 Block diagram of a base station device implementing multi-stage soft time-frequency multiplexing in the downlink.
  • Figure 10 Block diagram of a base station device implementing multi-stage soft time-frequency multiplexing on the uplink.
  • FIG. 11 Block diagram of a terminal device implementing multi-level soft time-frequency multiplexing in a wireless communication system.
  • FIG. 12A The time-frequency plane is divided into four sets of resource elements from the frequency dimension.
  • FIG. 12B The time-frequency plane is divided into four groups of resource elements from the time dimension.
  • FIG. 12C The time-frequency plane is divided into four groups of resource elements from two dimensions of time and frequency.
  • Figure 13 Power density template for multi-stage soft time-frequency multiplexing, two resource groups, two adjacent cells.
  • Figure 14 Coverage of each sub-resource group of multi-stage soft time-frequency multiplexing, two resource groups, and two adjacent cells.
  • Figure 15 Coverage of each sub-resource group of multi-stage soft time-frequency multiplexing, two resource groups, and a hierarchical cell scenario.
  • Figure 16 Multi-level soft time-frequency multiplexed power density template, three resource groups, two adjacent cells.
  • Figure 17 Coverage of each sub-resource group of multi-stage soft time-frequency multiplexing, three resource groups, and two adjacent cells.
  • Figure 18 Power density template for multi-stage soft time-frequency multiplexing, two resource groups, three adjacent cells.
  • Figure 20 Coverage of each sub-resource group of multi-stage soft time-frequency multiplexing, two resource groups, three adjacent sectors.
  • Time and frequency are resources of a wireless communication system, and the time-frequency resources used by the wireless communication system in the present invention are labeled S.
  • S can be a time-frequency plane B ⁇ T.
  • B is the spectrum used by the wireless communication system, and may be a continuous spectrum or a series of discontinuous spectrum.
  • T is a period of time, generally continuous. It can also be discontinuous, but it is rare to be discontinuous.
  • Most wireless communication systems communicate by dividing time resources into equal-length time slices (called frames).
  • the frame length of the LTE system is 10 ms, and one frame is further divided into 10 1 ms subframes. Therefore, in the time dimension, the subframe can be used as the partition granularity of the resource unit; in the frequency dimension, on the one hand, each carrier has a certain value.
  • Width such as WCDMA system carrier bandwidth is 5MHz, LTE carrier bandwidth has 1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz and 20MHz 6 kinds of bandwidth, so the carrier width can be used as the partitioning granularity of resource units.
  • the subcarrier width of LTE is 15 kHz.
  • the basic unit of resource allocation in LTE is 12 subcarriers, that is, 180 kHz, then 180 kHz can be used as the division granularity of the resource unit of the LTE system in frequency.
  • a resource unit can be selected as a partitioning granularity of a frequency dimension ⁇ a granularity of a time dimension, and the transmission power density can be separately set.
  • S is a time-frequency plane B ⁇ T.
  • some of the time-frequency plane B ⁇ T is used for some specialized purposes.
  • part of the time-frequency Resources are used as Common Reference Signals (CRS).
  • CRS Common Reference Signals
  • S may be part of the time-frequency plane B x T.
  • S is the remainder of the time-frequency plane that removes the CRS occupied resources.
  • the time-frequency resource S can have different division modes. 12A, 12B, and 12C, respectively, the time-frequency plane B ⁇ T is divided into four groups of resource units B1, B2, B3, and B4 from two dimensions of frequency dimension, time dimension, and time frequency, and each group may include one or Multiple resource units.
  • Each of the four resource elements B1, B2, B3, and B4 may be a continuous whole block resource or a discontinuous time-frequency resource.
  • One implementation of the multi-stage soft time-frequency multiplexing is to divide the time-frequency plane B ⁇ T into two resource groups, the first resource group includes B1 and B2, and the second resource group includes B3 and B4.
  • B1 and B3 are primary resource groups
  • B2 and B4 are secondary resource groups.
  • B2 and B4 are the primary sub-resource groups
  • B1 and B3 are the sub-sub-resource groups.
  • h (i) 1 is used as the reference, the relative gain of each power density upper limit can be taken as -12dB, -8dB, -4dB, 0dB, and the value of h (i) 1 can be determined according to the coverage size of the cell, for example, Take 45dBm/20MHz.
  • FIG. 13 is a power density template of such an embodiment
  • the time-frequency plane B ⁇ T may also adopt other methods of dividing resource groups, for example, the first resource group includes B1 and B3, and the second resource group includes B2 and B4.
  • B1 and B2 are selected as the primary sub-resource group
  • B3 and B4 are the sub-sub-resource groups
  • B3 and B4 are selected as the main sub-resource groups
  • B1 and B2 are the sub-sub-resource groups.
  • Such an implementation method can connect together sub-resource groups with similar power density upper limits.
  • continuous resources facilitate the identification and allocation of resources.
  • the resource number of B1 is 1 to 50
  • the resource number of B2 is 51 to 100.
  • the tag of 40 to 80 can express resource allocation across two sub-resource groups. If the resource numbers of B1 and B2 are not connected, it needs to be expressed separately in two segments, which is troublesome.
  • the combination mode of the power density templates of the two cells can be extended on multiple cells on one curve to form an overlay on a linear region, that is, the PDM of two cells is repeated in such a manner: cell 1, cell 2, Cell 1, Cell 2, Cell 1, Cell 2.
  • the power density template of Figure 13 can also be applied to the hierarchical cell structure of Figure 15.
  • cell 1 is a macro cell for wide coverage
  • cell 2 is a micro cell for wide coverage of blind spots or hotspots, and the cell radius is relatively small, and is completely or partially within the coverage of cell 1. .
  • the time-frequency resource S can be divided into more resource groups.
  • the first resource group contains B1 and B6, the second resource group contains B2 and B5, and the third resource group contains B3 and B4.
  • B1, B2, and B3 are primary resource groups, and B6, B5, and B4 are secondary resource groups.
  • B6, B5, and B4 are primary resource groups, and B1, B2, and B3 are secondary resource groups.
  • each power density upper limit can be taken as -15dB, -12dB, -9dB, -6dB, -3dB, 0dB. It can be seen that in this power density template, the upper limit of the power density of the sub-resource group is monotonously changed with the sequence number of the resource unit. In the scenario of two neighboring cells, the coverage of each sub-resource group is as shown in FIG. 17.
  • Figure 18 shows a power density template for a multi-stage soft time-frequency multiplexing technique applied to three adjacent cells on a plane.
  • the time-frequency resource S is divided into six groups of resource units B1, B2, B3, B4, B5, and B6, and is divided into two resource groups, the first resource group includes B1, B2, and B3, and the second resource group includes B4 and B5. B6.
  • B1 and B4 are the primary sub-resource groups, and the others are the sub-sub-resource groups.
  • B2 and B5 are the primary sub-resource groups, and the others are the de-sub-resource groups.
  • B3 and B6 are the primary sub-resource groups, and the others are the de-sub-resource groups.
  • FIG. 19 is a coverage range of each sub-resource group in an omni-directional cell scenario
  • FIG. 20 is a coverage range of each sub-resource group in a three-sector scenario.
  • the primary sub-resource groups can still be connected together to facilitate the identification and allocation of resources.
  • the first resource group includes B1, B3, and B5, and the second resource group includes B2, B4, and B6.
  • B1 and B2 are the primary sub-resource groups, and the others are the sub-sub-resource groups.
  • B3 and B4 are the primary sub-resource groups, and the others are the de-sub-resource groups.
  • B5 and B6 are the primary sub-resource groups, and the others are the de-sub-resource groups.
  • the combined mode of the power density templates of the three cells can be extended on the plane to cover the entire plane.
  • the primary sub-resource group accounts for 1/3 of the ratio in each resource group.
  • Other ratios, such as 1/4, can also be selected to meet the requirements of an irregular cell or a stereo network.
  • the base station can change the PDM setting of the cell to adapt to changes in services, traffic distribution, and wireless propagation environment.
  • the base station needs to determine whether a terminal is within the coverage of a sub-resource group, thereby determining whether the sub-resource group can be used by the terminal.
  • the base station continuously transmits a constant power reference signal, which can have different choices.
  • a common reference signal CRS can be selected as a reference signal.
  • the broadcast channel or synchronization channel of the cell may also be selected as a reference signal.
  • the receiving strength RSRP of the terminal to the reference signal is generally selected as the receiving power of the reference signal, and the unit is generally dBm. Since the transmit power of the reference signal is constant, the closer the terminal is to the cell edge, the smaller the received RSRP, so the RSRP can be used as a representation of the location of the terminal in the cell. Since the up and down are correlated in large-scale fading, this method works well above and below, but may differ in specific values.
  • An RSRP threshold is set for each sub-resource group.
  • the RSRP threshold is geographically corresponding to a curve surrounding the base station antenna. The area enclosed by the curve is the coverage of the sub-resource group.
  • a sub-resource group with a higher power density upper limit has a larger coverage, and the RSRP received at the remote terminal that is covered is relatively small, so a relatively small RSRP threshold should be set.
  • an offset amount may be additionally set on the basis of the RSRP measured by the terminal, which is generally expressed in dB.
  • the RSRP threshold of the sub-resource group is compared.
  • the RSRP can be corrected in an increasing direction, so that the terminal can use one sub-resource group in a larger area; for a terminal with weak processing capability, the RSRP can be reduced in a direction To fix, so that the area in which the terminal uses the resource group is reduced. If the RSRP is not corrected, it is equivalent to an RSRP offset of 0 dB, which is a special list.
  • the RSRP offset can be stored in the mobile phone as a parameter of the terminal, and the parameter is reported to the base station when accessing a cell. If the terminal does not report the RSRP offset, the base station can be set to 0 dB by default. The base station can modify the RSRP offset of the terminal when it considers it necessary.
  • the sub-resource group list can be corrected by using the terminal RSRP with each sub-resource group RSRP threshold comparison is established.
  • RSRP thresholds are also basically unchanged. Therefore, a sorting method can be used to quickly establish a sub-resource group list covering one terminal. For example, the system has a total of six sub-resource groups, and their RSRP thresholds are arranged from small to large:
  • the terminal sets a -3dB RSRP offset, that is, the corrected terminal's RSRP is -71dBm, the sub-resource list that covers the terminal is 1, 3, and 6; if the terminal's threshold is offset 10dB, the corrected RSRP is -58dBm, then the sub-resource group list covering the terminal is 1, 3, 6, 5, 4.
  • the terminal may be mobile, and the list of sub-resource groups covering it may also change. Therefore, the terminal can periodically measure the RSRP and report it to the base station, and the base station updates the sub-resource group list covering the terminal according to the RSRP measurement report of the terminal.
  • the period in which the terminal reports RSRP may be subject to availability. For example, if the terminal moves faster, a shorter reporting period is used. Conversely, if the terminal moves at a slower speed, a longer reporting period is used.
  • the terminal may use a sub-resource group that covers the terminal, and may not use a sub-resource group that does not cover the terminal.
  • This principle is only a functional principle.
  • the following resource allocation methods can be used:
  • Allocating resources for a user can allocate resources to any of the sub-resource groups that cover its terminal. However, from the perspective of system performance, if a large coverage sub-resource group is allocated to the end user of the cell center prematurely, there is no end user at the cell edge that can allocate resources, and the small-overlay sub-resource group is idle. So priority is given Allocating resources to terminals in a small sub-resource group allows resources to be used most efficiently.
  • the resources allocated to each user are not limited to time and frequency, but may be other resources, such as a code channel of a CDMA system.
  • a resource allocation method based on multi-stage soft time-frequency multiplexing can be applied to uplink and downlink.
  • the resource is allocated at the base station and the transmitter is at the terminal, so the base station transmits the resource allocation information to the terminal, thereby enabling the terminal to transmit the user data on the allocated resource.
  • the resource allocation information can be directly used to control the transmitter to transmit user data.
  • the base station also sends resource allocation information to the terminal so that the terminal can receive data on the allocated resources.
  • Resource allocation can take different forms. If the communication system has multiple carriers, each sub-resource group is one carrier, and each carrier forms a logical cell. In this case, selecting a sub-resource group means selecting a logical cell, and accessing the logical cell through a cell selection reselection or handover process, and then obtaining the required resources.
  • selecting a sub-resource group means selecting a logical cell, and accessing the logical cell through a cell selection reselection or handover process, and then obtaining the required resources.
  • a wideband OFDM system such as LTE
  • multiple users use a shared channel in common, and multiple sub-resource groups can be divided on one shared channel, and resource allocation is implemented by scheduling.
  • the transmitter needs to know the PDM information so that the actual transmit power density on all sub-resource groups does not exceed the corresponding power density upper limit.
  • the PDM is set by the base station, and the transmitter can be directly notified.
  • the PDM is also set by the base station, and the terminal in the cell needs to be notified in some way. Since the PDM information is a configuration parameter of the cell, it is suitable to be broadcast as a system message, and all terminals in the cell can receive it. This system message can be encapsulated into an RRC system message in the 3GPP protocol system.
  • the following data structure can represent PDM information, including the following fields:
  • Field 1 indicates the number of sub-resource groups.
  • Field 2 the resource range of each sub-resource group, the case of continuous resources can be expressed in the form of start/end, and the case of non-contiguous resources can be expressed by multiple start/end methods;
  • Field 3 the highest power density upper limit as the reference value
  • Field 4 the upper limit of the power density of each sub-resource group relative to the highest power density upper limit, expressed in dB;
  • Each field uses a certain number of bits to represent multiple values. For example, for field 1, if it is represented by 2 bits, it can represent the number of 4 seed resource groups:
  • the base station can modify the RSRP offset of the terminal. For example, on a certain sub-resource group, for various reasons, the power control command often tries to make the power density of the transmitter exceed the set power density upper limit, so that the RSRP offset of the terminal can be reduced, so that the sub-resource group is The sub-resource group covering the terminal is removed, thereby switching to a sub-resource group with a higher power density threshold. Conversely, if the actual transmit power density of a terminal is always much smaller than the upper limit of the power density of the smallest sub-resource group, the RSRP offset of the terminal may be increased, so that a sub-resource group with a smaller power threshold is added to the coverage of the terminal.
  • a list of sub-resource groups thereby switching to a sub-resource group with a smaller power density threshold.
  • the terminal is far from the base station and has a higher data rate requirement. According to its current RSRP offset, all resources covering it are still allocated to it and still cannot meet its requirements. If the priority of this terminal is high and the base station decides to allocate more resources to it, it can increase its RSRP offset so that there are more resources in the list of sub-resource groups covering it.

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Abstract

本发明公开了一种无线资源复用方法、基站设备、终端设备和无线通信系统。该系统至少包含两个相邻小区Ci(i＝1，2)，使用的时频资源记为S，将该时频资源S划分成至少两个资源单元，每个该资源单元是一个时间-频率资源块。该方法包括：把该时频资源S划分成N个互不重叠的资源组，记为RGn(n＝1，2，…，N)，N是大于1的整数；每个该资源组包括至少两个该资源单元；在小区Ci(i＝1，2)，把RGn(n＝1，2，…，N)分成互不重叠的两部分，对一部分设置功率密度上限h(i) n，称为主子资源组；对另一部分设置功率密度上限l(i) n，称为副子资源组，各子资源组满足关系：l(i) 1/h(i) 1＜l(i) 2/h(i) 2＜…＜l(i) N/h(i) N≤1；两个相邻小区Ci(i＝1，2)在每个资源组上的主子资源组均互不重叠。

Description

一种无线资源复用方法、基站设备、终端设备和无线通信系统
相关申请的交叉引用
本申请要求享有于2013年12月28日提交的名称为“一种多级软时频复用和资源分配的方法、设备和系统”的中国专利申请CN201310735224.2和于2014年03月08日提交的名称为“一种多级软时频复用和资源分配的方法、设备和系统”的中国专利申请CN201410082468.X的优先权，该了两份申请的全部内容通过引用并入本文中。
技术领域
本发明属于无线通信领域，尤其涉及一种无线资源复用方法、基站设备、终端设备和无线通信系统。
背景技术
LTE标准在制定之初提出了提高小区边缘速率的要求。针对这一要求，业界提出了多种方案，其中比较著名的有软频率复用和分数频率复用。目前，这些技术被广泛研究和应用，并发展成为LTE的“小区间干扰协调”这一关键技术特性，也就是ICIC(Inter cell interference coordination)。
在分数频率复用当中，所用的频谱被划分成两部分，每个部分使用不同的复用因子。如图1所示，频谱的B1(＝B11+B12+B13)部分采用复用因子3，而B2+B3部分采用复用因子1。图1当中的曲线表示发射机的发射功率密度的上限，发射机的功率密度可以小于等于这个上限，而不能超过这个上限。这条曲线也叫做功率密度模版(Power Density Mask)，简称为PDM。
复用因子为3的B1部分，所用频段的发射功率密度上限比较高，可以覆盖整个小区；而复用因子为1的B2+B3部分，发射功率密度上限比较低，只覆盖小区的内部区域。分数频率复用的覆盖情况如图2和图3所示。图2显示的全向小区的情况，而图3显示的是三扇区的情况，二者是类似的。为了行文方便，在本发明当中，全向小区和扇区统一称为小区。
图2和图3当中的频段符号，也就是B11，B12，B13，B2，B3，放置于其覆盖范围最远边界的内侧。B2，B3放置于小区内部，表示只能够覆盖小区的内部 区域，而B11，B12，B13放置于小区边缘，表示可以覆盖整个小区，当然也可以覆盖小区内部，但是在小区内部就不再标出了。
图2和图3给出的是规则的六边形小区，小区的内部表示为一个规则的圆形或者椭圆。在实际情况当中，由于无线传播环境的复杂性，小区的形状一般是不规则的，小区的内部和边缘的分界线也一般是一个复杂的形状。
小区边缘的干扰比较大，通过较大的复用因子3避免了相邻小区的干扰，从而提高了信号的信噪干扰比(SINR)；而小区内部的干扰比较小，通过较小的复用因子1达到比较高的频谱效率，因此分数频率复用得到了人们的重视。
分数频率复用适用于上行(信号由终端到基站)和下行(信号由基站到终端)。
分数频率复用的主要缺点在于每个小区不能够利用所有的频谱，并且小区边缘可以利用的频谱比较少。
软频率复用技术在文献“杨学志，一种在无线通信系统中实现频率软复用的方法，CN1783861”当中提出，其功率密度模版如图4所示，图5和图6显示的是各个频段的覆盖情况。
在图4所示的软频率复用技术示例当中，频谱被划分成了三段，记为B1、B2、B3。每个小区选一个频段设置一个比较高的功率密度上限，称作主载波，可以覆盖到整个小区。其他的频段设置一个比较低的功率密度上限，称作副载波，只能够覆盖小区的内部区域。小区边缘的用户只能使用本小区的主载波，而小区内部的用户既可以使用主载波，也可以使用副载波。
如图5或者图6，在小区1当中B1是主载波，有较高的功率密度上限，可以覆盖整个小区，而B2和B3是副载波，有较低的功率密度上限，只能够覆盖小区内部区域。小区边缘的用户只能够使用主载波B1，而小区内部的用户，既可以使用主载波B1，也可以使用副载波B2和B3。
在软频率复用技术当中，相邻小区的主载波互不重叠，因此分属于不同相邻小区的边缘用户之间相互没有干扰。在小区边缘，与同频复用相比虽然可用带宽减少了，但是信干噪比得到比较大的提高，足以补偿带宽上的损失，通信速率还是可以得到比较大的提高。在小区内部，本小区的信号比较强，而邻区干扰比较小，所有的带宽都可以得到利用，具有较高的频谱效率。软频率复用克服了分数频率复用的缺点，得到了广泛的研究和应用，是目前ICIC领域的主流技术。
从这里也可以看出，软频率复用本质上是一种网络规划技术，为每个小 区的资源分配提供了一个约束框架。在这个约束框架下进行小区内的资源分配，可以实现较好的干扰模式，提高整个网络的性能。
软频率复用是从频率维度划分通信资源的，而与频率并列的时间也是一种通信资源。如果把时间划分成若干时间片，在每个时间片上设置不同的功率密度上限，就是软时间复用技术；或者更一般地，把时间-频率平面划分成不同的区域，在时频平面上定义功率密度模版，就形成软时频复用技术。
软频率复用的缺点在于每个小区的功率密度模版只有两个等级，只是为小区内的资源分配提供了一个比较粗略的约束，还有比较大的性能提升空间。
如图7的两个相邻小区，小区1的主载波为B1，副载波为B2，小区1边缘有两个终端u11和u12，分别用f1和f2通信，f1和f2都属于B1。u12比u11更靠近小区边缘，用更大的功率通信。小区2的主载波为B2，副载波为B1。小区2内部有两个终端u21和u22，也分别用f1和f2通信。u21比u22更靠近小区中心，用更小的功率通信。上行和下行都是如此。这样形成的干扰模式是u11和u21相互干扰，u12和u22相互干扰。
但是这是一种较差的干扰模式，较好的干扰模式如图8所示。因为u12比u11更靠近小区边缘，更加容易受到邻区的干扰，因此较好的模式是把u12与干扰小的u21配置在同一个频率上，而把u11与干扰大的u22配置在同一个频率上。这样的话，传播条件最差的用户u12受到的干扰最小，可以获得更高的速率；而u12造成的干扰最大，这个最大的干扰施加于传播条件最好的用户u21之上。相比于图7的干扰模式，提升了小区边缘的最低速率，而降低了小区中心的最高速率，可以提高用户体验并减少投诉，对运营是有利的。
但是，在现有的软频率复用方案当中，由于只有两个功率密度等级，无法提供更为精确的约束，一般无法实现这种较好的干扰模式，特别在比较复杂的网络当中更是如此，系统的性能有较大的提升空间。
发明内容
为了进一步优化软频率复用技术的干扰模式，提升网络的性能，本发明提出一种在无线通信系统当中实现多级软时频复用和资源分配的方法、设备和系统。
本发明考虑的无线通信系统至少包含两个相邻的小区Ci(i＝1，2)，使 用时频资源S进行通信。在本发明当中，小区是一个地理区域，使用全部的时频资源S。在实际的系统当中，即使在同一个地理区域，两个不同的载波也可能形成两个逻辑小区，有不同的小区标识。在本发明当中，这两个逻辑小区属于同一个小区。小区可以是全向小区，也可以是扇区。两个小区相邻，是指两个小区具有重叠的覆盖区域。因为要在不同的时频资源上设置不同的功率密度，因此要求无线通信系统能够将时频资源S划分成若干(如后面具体实施例提到的至少两个)个资源单元，每个资源单元是一个时间-频率资源块，这样，可允许针对各个资源单元单独地设置发射功率密度。在根据本发明实施例的多级软时频复用技术方案中：
把时频资源S划分成N个互不重叠的资源组，记为RGn(n＝1，2，...，N)，N是大于1的整数；每个资源组包括若干个(如后面实施例所述的至少两个)资源单元；
在小区Ci(i＝1，2)，把RGn(n＝1，2，...，N)划分成互不重叠的两部分，针对其中一部分设置功率密度上限h(i) n，称为RGn的主子资源组；针对另外一部分设置功率密度上限l(i) n，称为RGn的副子资源组，主子资源组和所述副子资源组统称为子资源组；各个子资源组的功率密度上限满足关系：l(i) 1/h(i) 1＜l(i) 2/h(i) 2＜...＜l(i) N/h(i) N≤1，并且如果N＝2，l(i) 2≠h(i) 2；设置每个子资源组的功率密度上限，使得发射机在每个所述子资源组上的发射功率密度不超过该子资源组的功率密度上限；
相邻小区在每个资源组上的主子资源组互不重叠。
在本发明的一个实施例当中，主子资源组和副子资源组合称为子资源组；时频资源S上的资源组和子资源组的划分情况，以及每个子资源组的功率密度上限称为PDM信息。
可以看出，在多级软时频复用技术的N个资源组当中，每一个资源组上都采用了软时频复用技术。每个资源组上的副载波和主载波的功率密度上限的比值l(i) n/h(i) n，在两个相邻小区都随资源组序号的增加而增大。也就是说，如果保持资源组的划分方法，而只是重新指定资源组的序号，把两个相邻小区的l(i) n/h(i) n从小到大排序得到两个序列，其对应的资源组序号序列是相同的。
在实际的应用当中，合理的设置是较高的功率密度门限对应较大的覆盖范围，因此一般进一步要求l(i) 1≤l(i) 2≤...≤l(i) N≤h(i) N≤...≤h(i) 2≤h(i) 1(i＝1，2)。这样的设置使得一个小区功率密度上限最高/次高的资源与相邻小区功率密度上限最低/次低的资源相互干扰，实现了优化的干扰模式。在干扰受限的场景下，也就是干扰相比噪声大很多的情况下，如果所有小区的某个资 源组上的功率密度都放大一个相同的因子，也就是信号和干扰都放大相同的比例，并不会影响通信质量。因此，在l(i) 1≤l(i) 2≤...≤l(i) N≤h(i) N≤...≤h(i) 2≤h(i) 1(i＝1，2)的基础上，在l(i) n和h(i) n(i＝1，2)上都乘以一个相同的放大因子，l(i) n/h(i) n保持不变，通信质量也保持不变，但是功率密度上限的排序可能会被破坏，并出现功率密度上限高反而覆盖范围小的情况，造成功率浪费。
也可以进一步要求l(i) 1＜a(i)＜b(i)＜h(i) 1(i＝1，2)，其中a(i)和b(i)是h(i) n(n＝2，3，...，N)和l(i) n(n＝2，3，...，N)当中任意不同的两个，就是说最少设置4个不同的功率密度门限。
软频率复用当中只有两个功率密度等级，小区也被相应地划分为小区边缘和小区中心两个区域。而在多级软时频复用当中，假如N＝2，小区边缘又进一步被划分成两个区域，可以叫最边缘和次边缘区域，而小区中心也被划分成两个区域，可以叫最中心和次中心区域。一个小区最边缘的终端分配功率密度上限最高的资源，而这个资源在相邻小区的功率密度上限最低，只能分配给最中心的用户，从前面的讨论可以看出，这是较好的干扰模式，避免了最边缘和次中心相互干扰的较差的干扰模式，提高了系统的性能。
从这个分析还可以看出，资源组的数目N越大，功率密度上限的等级越多，约束就越精细，干扰模式的匹配就越精确。
多级软时频复用技术可以应用于上行和下行。
本发明所说的基站，是指形成和控制一个小区的系统设备或者功能，可能为一个设备节点，也可能分布于多个设备节点。
基站可以根据情况修改本小区的PDM参数设置。
在应用于上行的情况下，基站将PDM信息在其形成的小区内广播。在上行的时候，终端需要PDM信息来控制发射机的发射功率密度，所以基站需要把PDM信息发送给终端。因为PDM信息可以认为是小区的配置参数，并且基本保持不变，所以作为系统消息从广播信道发送是比较好的选择。
和软频率复用类似，多级软时频复用技术所确定的PDM，为小区内的资源分配提供了约束框架。为了实现小区内的资源分配，在每个小区，为所有的子资源组确定一个覆盖范围(换而言之，为各个子资源组分别确定一个覆盖范围)，并且为具有较高的功率密度上限的子资源组设置较大的覆盖范围。
基站持续地发射一个功率恒定的参考信号，终端对参考信号的接收强度记为RSRP；为各个子资源组分别确定一个RSRP门限；对功率密度上限较 高的子资源组设置较低的RSRP门限，对功率密度上限较低的子资源组设置较高的RSRP门限。
终端测量RSRP，并且报告给基站；对于一个终端，为其设置一个RSRP偏置量；终端报告的RSRP，用该偏置量进行修正该终端报告的RSRP，得到修正后的终端RSRP。基站分别将所述修正后的终端RSRP与各个子资源组的RSRP门限比较，将RSRP门限小于等于所述修正后的终端RSRP的子资源组判定为覆盖该终端的子资源组，以建立覆盖该终端的子资源组列表。也就是说，将修正后的终端RSRP与一个子资源组的RSRP门限比较，如果大于等于该门限，则判定该终端处于该子资源组的覆盖范围；把修正的RSRP和所有的子资源组的RSRP门限均分别进行比较，从而建立覆盖此终端的子资源组列表。
RSRP偏置量是终端的一个参数，当终端接入一个小区的时候报告给基站，并且基站可以修改终端的RSRP偏置量参数。
基站对所有的子资源组根据其RSRP门限大小排成一个序列；把序列当中RSRP门限小于等于修正后的终端RSRP的所有子资源组添加至覆盖该终端的子资源组列表。采用排序的方法，可以比较快速地建立覆盖该终端的子资源组列表。
在移动通信系统当中，终端可能是移动的，覆盖它的子资源组列表也会变化。因此终端可以周期性地测量RSRP，并且报告给基站，基站根据终端的RSRP测量报告更新覆盖此终端的子资源组列表。
终端可以使用覆盖该终端的子资源组(即，子资源组列表中的子资源组)，不使用不在所述所述子资源组列表中的子资源组。
本发明的用户是指应用层面终端与基站之间的一个数据通道，可以是上行或者下行，比如3GPP媒体接入控制(MAC)协议当中的一个逻辑信道。
本发明还揭示了一种基于多级软时频复用的资源分配方法，步骤为：为每个参与资源分配的终端建立覆盖该终端的子资源组列表；对每个需要发送数据的用户，首先在覆盖其终端的具有最小覆盖范围的子资源组当中分配资源；如果资源不够，则在具有第二最小覆盖范围的子资源组当中分配资源，依次类推；如果此用户获得了所需的资源，则对下一个用户重复这个过程，直到所有用户获得所需资源，或者没有可分配的资源。
为一个用户分配资源，单从功能的角度来说，在任何一个覆盖其终端的子资源组当中为其分配资源都可以。但是从系统性能的角度来说，如果把大覆盖的子资源组过早地分配给小区中心的终端用户，会导致小区边缘的终端 用户没有可分配资源，而小覆盖的子资源组闲置不用的情况。所以优先在覆盖较小的子资源组当中为终端分配资源，这样使得资源得到有效的利用，特别是在网络负载比较大的情况下。
在本发明当中，资源分配的结果称为资源分配信息。
基于多级软时频复用的资源分配方法可以应用于上行和下行。在应用于下行的时候，由于资源分配和数据发送都在基站，因此资源分配信息可以直接用来控制发射机发送用户数据。在应用于上行的时候，资源分配在基站，而发射机在终端，因此基站把资源分配信息发送给终端，从而使得终端能够在分配的资源上发射用户数据。
还可以进一步设置功率密度模版，使得在C1和C2当中的至少一个小区，至少两个主子资源组的资源序号相连。这里的资源序号指的是在分配资源的时候用来标识一个资源所用的序号。这样做的好处是，如果一个终端需要在这两个主子资源组上分配资源，对资源的标识会比较方便。特别是，如果所有的主子资源组的资源序号都连接在一起，那么副子资源组的资源序号的连续性也比较好，对资源的标识就更方便了。
本发明还揭示了一种在无线通信系统当中实现多级软时频复用的基站设备，称为BS0。BS0主要包含以下模块：
发射模块：持续地发射一个功率恒定的参考信号；
接收模块：接收终端发来的RSRP和RSRP偏置量，把利用RSRP偏置量修正后的RSRP测量报告发送给终端覆盖子资源组列表生成模块；
PDM设置模块：把时频资源S划分成N个不相互重叠的资源组，记为RGn(n＝1，2，...，N)，N是大于1的整数，每个资源组包含至少两个个资源单元；把RGn(n＝1，2，...，N)划分成互不重叠的两部分，其中一部分设置功率密度上限hn，称为RGn的主子资源组；另外一部分设置功率密度上限ln，称为RGn的副子资源组；各个子资源组的功率密度上限满足关系：l(i)1/h(i)1＜l(i)2/h(i)2＜...＜l(i)N/h(i)N≤1，l(i)1≤l(i)2≤...≤l(i)N≤h(i)N≤...≤h(i)2≤h(i)1，并且如果N＝2，l(i)2≠h(i)2；把PDM信息发送给覆盖门限生成模块和发射模块；
覆盖门限生成模块：为每个子资源组确定一个RSRP门限；对功率密度上限较高的子资源组设置较低的RSRP门限，对功率密度上限较低的子资源组设置较高的RSRP门限；把RSRP门限信息发送给终端覆盖子资源组列表生成模块；
终端覆盖子资源组列表生成模块：针对各个终端，根据该终端发来的 RSRP偏置量来修正所述终端发来的RSRP，得到修正后的RSRP，把修正后的终端RSRP与各个子资源组的RSRP门限分别进行比较，将RSRP门限小于等于所述修正后的终端RSRP的子资源组判定为覆盖该终端的子资源组，以建立覆盖该终端的子资源组列表。。
基站设备BS0在应用于下行的时候(为了便于说明，称为BS1)。如图9所示，BS1还可进一步包括以下模块：
资源分配模块：对每个需要分配资源的用户终端，首先在覆盖该终端的具有最小覆盖的子资源组当中分配资源，如果资源不够，则在第二最小覆盖的子资源组当中分配资源，依次类推；如果该终端获得了所需的资源，则对下一个用户重复这个过程，直到所有需要资源的用户获得了所需资源，或者没有可分配的资源；把资源分配信息发送给发射模块。在这种情况下，前述发射模块还进一步用于：根据资源分配信息给用户数据安排资源，发射用户数据，以及进行控制使得发射机在各个子资源组上的发射功率密度均不超过各个子资源组各自对应的功率密度上限。
当基站设备BS0应用于上行的时候，(为了便于说明，称为BS2)，如图10所示，进一步包括以下模块和功能：
终端覆盖子资源组列表生成模块：对需要分配资源的终端，把覆盖该终端的子资源组列表发送给资源分配模块；
资源分配模块：对需要分配资源的用户终端，首先在覆盖该终端的具有最小覆盖的子资源组当中分配资源，如果资源不够，则在第二最小覆盖的子资源组当中分配资源，依次类推；如果该终端获得了所需的资源，则对下一个终端重复这个过程，直到所有需要资源的用户获得了所需资源，或者没有可分配的资源；把资源分配信息发送给发射模块；
在这种情况下，发射模块进一步用于：将PDM信息在小区内广播，把所述资源分配模块确定的资源分配信息发送给终端。
本发明还揭示一种在无线通信系统当中实现多级软时频复用的终端设备，如图11所示，主要包括如下模块和功能：
接收模块：接收基站发射的参考信号，发送给测量模块；接收基站广播的PDM信息；接收资源分配信息；把PDM信息和资源分配信息发送给发射模块；
测量模块：测量RSRP，并形成RSRP测量报告，所述RSRP测量报告包括所测量的终端RSRP，发送给发射模块；
发射模块：向基站发送RSRP测量报告和RSRP偏置量；根据资源分配信息为用户数据安排(分配)资源，发射用户数据；进行控制使得发射机在各个子资源组上的发射功率密度不超过其对应的功率密度上限。
本发明还揭示了一种实现多级软时频复用的无线通信系统，至少包含两个形成两个相邻的小区的如前所述的技术方案所述的基站设备(BS0、BS1或BS2)，并且这两个相邻小区在每个资源组上的主子资源组均互不重叠，从而实现本发明提出的多级软时频复用技术。
附图说明
附图用来提供对本发明的进一步理解，并且构成说明书的一部分，与本发明的实施例共同用于解释本发明，并不构成对本发明的限制。
图1.分数频率复用的功率密度模版。
图2.分数频率复用各频段的覆盖范围，全向小区场景。
图3.分数频率复用各频段的覆盖范围，三扇区场景。
图4.软频率复用的功率密度模版。
图5.软频率复用各频段的覆盖范围，全向小区场景。
图6.软频率复用各频段的覆盖范围，三扇区场景。
图7.软频率复用较差的干扰模式。
图8.软频率复用较好的干扰模式。
图9.在下行实现多级软时频复用的基站设备的结构框图。
图10.在上行实现多级软时频复用的基站设备的结构框图。
图11.在无线通信系统当中实现多级软时频复用的终端设备的结构框图。
图12A.时频平面从频率维度划分成四组资源单元。
图12B.时频平面从时间维度划分成四组资源单元。
图12C.时频平面从时间频率两个维度划分成四组资源单元。
图13.多级软时频复用的功率密度模版，两资源组，两相邻小区。
图14.多级软时频复用的各子资源组的覆盖范围，两资源组，两相邻小区。
图15.多级软时频复用的各子资源组的覆盖范围，两资源组，分层小区场景。
图16.多级软时频复用的功率密度模版，三资源组，两相邻小区。
图17.多级软时频复用的各子资源组的覆盖范围，三资源组，两相邻小区。
图18.多级软时频复用的功率密度模版，两资源组，三相邻小区。
图19.多级软时频复用的各子资源组的覆盖范围，两资源组，三相邻全向小区。
图20.多级软时频复用的各子资源组的覆盖范围，两资源组，三相邻扇区。
具体实施方式
为使本发明的目的、技术方案和优点更加清楚，以下结合附图对本发明作进一步地详细说明。
时间和频率是无线通信系统的资源，本发明当中的无线通信系统所用的时频资源标记为S。在通常的情况下，S可以为一个时频平面B×T。这里的B是无线通信系统所用的频谱，可以是一段连续的频谱，也可以是几段不连续的频谱。而T是一段时间，一般来说是连续的。也可以不连续，但是不连续的情况比较少见。
多数无线通信系统采用把时间资源划分成等长的时间片(称为帧)的方式进行通信。比如LTE系统的帧长为10ms，一帧又进一步划分成10个1ms的子帧，因此在时间维度，子帧可以作为资源单元的划分粒度；在频率的维度，一方面每个载波有一定的宽度，比如WCDMA系统的载波带宽为5MHz，LTE的载波带宽有1.4MHz，3MHz，5MHz，10MHz，15MHz和20MHz 6种带宽，因此载波的宽度可以作为资源单元的划分粒度。
对于基于OFDM技术的无线通信系统，在一个载波的范围内，还可以在频率的维度划分为更小的子载波，比如LTE的子载波宽度为15kHz。为了避免资源的分配过于零散，LTE里面资源分配的基本单位是12个子载波，也就是180kHz，那么180kHz可以作为LTE系统的资源单元在频率上的划分粒度。
一个资源单元可以选择为一个频率维度的划分粒度×时间维度的划分粒度，能单独设置发射功率密度。
通常的情况下，S为一个时频平面B×T。但是在一些情况下，时频平面B×T当中的一部分用于一些专门的用途。比如在LTE当中，一部分时频 资源用作了公共参考信号(CRS)。在这种情况下，S可以是时频平面B×T的一部分。在LTE的例子当中，S是时频平面当中去掉CRS占用资源的剩余部分。
时频资源S可以有不同的划分方式。如图12A、图12B和图12C，分别把时频平面B×T从频率维度、时间维度和时间频率两个维度划分成四组资源单元B1、B2、B3、B4，每组可以包括一个或者多个资源单元。
B1、B2、B3、B4四组资源单元当中的每一个，可以是连续的一整块资源，也可以是不连续的几块时频资源。
多级软时频复用的一种实施方式是，把时频平面B×T划分成两个资源组，第一资源组包含B1和B2，第二资源组包含B3和B4。在小区1，B1和B3是主子资源组，B2和B4是副子资源组。在小区2，B2和B4是主子资源组，B1和B3是副子资源组。在两个小区，一般情况下，设置各个子资源组覆盖范围不同，功率密度上限不相等，满足关系：l(i) 1＜l(i) 2＜h(i) 2＜h(i) 1，(i＝1，2)。如果以h(i) 1为基准，各个功率密度上限的相对增益可以取为-12dB，-8dB，-4dB，0dB，h(i) 1的取值可根据小区的覆盖大小来确定，例如可以取45dBm/20MHz。图13是这种实施方式的功率密度模版，图14是两个相邻小区的场景下的各个子资源组的覆盖范围。在一些特殊的场合，也可以取等号，比如l(i) 1＜l(i) 2＜h(i) 2＝h(i) 1，l(i) 1＝l(i) 2＜h(i) 2＜h(i) 1。如果l(i) 1＜l(i) 2＝h(i) 2＜h(i) 1，(i＝1，2)，则方案就退化成分数频率复用(l(i) 1＝0)或者软频率复用与同频复用的组合(l(i) 1≠0)。
时频平面B×T也可以采用其他的划分资源组的方法，比如第一资源组包含B1和B3，第二资源组包含B2和B4。在小区1，选择B1、B2为主子资源组，B3、B4为副子资源组，而在小区2，选择B3、B4为主子资源组，B1、B2为副子资源组。这样的实施方法可以使得功率密度上限相近的子资源组连在一起。在一个终端需要在两个及以上功率密度上限相近的子资源组当中分配资源的时候，连续的资源有利于资源的标识和分配。比如B1的资源序号维1～50，B2的资源序号为51～100，40～80这样的标记就能表达跨两个子资源组的资源分配。如果B1、B2的资源序号不相连，就需要分两段分别表达，比较麻烦。
这两个小区的功率密度模版的组合模式可以在一条曲线上的多个小区上拓展，形成在一条线形区域上的覆盖，也就是这样的方式重复两个小区的PDM：小区1，小区2，小区1，小区2，小区1，小区2。
图13的功率密度模版也可以应用于如图15的分层小区结构。在这个结构当中，小区1是宏小区，用于广覆盖，而小区2是微小区，用于广覆盖盲点或者热点区域，其小区半径比较小，并完全处于或者部分处于小区1的覆盖范围内。
时频资源S可以划分成更多的资源组。比如图16所示的功率密度模版当中，划分成三个资源组。第一资源组包含B1和B6，第二资源组包含B2和B5，第三资源组包含B3和B4。在小区1，B1、B2、B3是主子资源组，B6、B5、B4是副子资源组。在小区2，B6、B5、B4是主子资源组，B1、B2、B3是副子资源组。在两个小区，功率密度上限都满足关系：l(i) 1＜l(i) 2＜l(i) 3＜h(i) 3＜h(i) 2＜h(i) 1，(i＝1，2)。如果以h(i) 1作为基准，各个功率密度上限的相对增益可以取为-15dB，-12dB，-9dB，-6dB，-3dB，0dB。可以看到，在这个功率密度模版当中，子资源组的功率密度上限是随资源单元的序号单调变化的。在两个相邻小区的场景下，各个子资源组的覆盖范围如图17所示。
还可以进一步提高资源组的数量。划分的资源组数量越多，功率密度上限的等级就越多，干扰模式就会更加优化，使得系统的性能提高。但是资源组的数量过多容易引起资源的碎片化，给资源分配带来麻烦。
多级软时频复用更典型的应用在于平面覆盖。图18所示的是应用于平面上三相邻小区的多级软时频复用技术的功率密度模版。时频资源S被划分成六组资源单元B1、B2、B3、B4、B5、B6，划分成两个资源组，第一资源组包含B1、B2、B3，第二资源组包含B4、B5、B6。在小区1，B1和B4是主子资源组，其他的是副子资源组。在小区2，B2和B5是主子资源组，其他的是副子资源组。在小区3，B3和B6是主子资源组，其他的是副子资源组。在三个小区，功率密度上限都满足关系：l(i) 1＜l(i) 2＜h(i) 2＜h(i) 1，(i＝1，2，3)。图19是全向小区场景下各个子资源组的覆盖范围，图20是三扇区场景下各个子资源组的覆盖范围。
在平面覆盖当中，虽然不能做到功率密度上限随着资源单元序号单调上升或者下降，但是仍然可以使得主子资源组连接在一起，方便资源的标识和分配。比如，第一资源组包含B1、B3、B5，第二资源组包含B2、B4、B6。在小区1，B1和B2是主子资源组，其他的是副子资源组。在小区2，B3和B4是主子资源组，其他的是副子资源组。在小区3，B5和B6是主子资源组，其他的是副子资源组。
三个小区的功率密度模版的组合模式可以在平面上进行拓展，从而覆盖整个平面。
在此实施例当中，在每个资源组，主子资源组占1/3的比例。也可以选择其他的比例，比如1/4，以满足不规则小区或者是立体组网的要求。
基站可以改变本小区的PDM设置，从而适应业务、流量分布、无线传播环境等方面的变化。
因为不同的子资源组上的发射功率密度上限不同，所以其覆盖范围也不同。因此基站需要确定一个终端是否在一个子资源组的覆盖范围之内，从而确定该终端是否可以使用该子资源组。
基站持续地发射一个功率恒定的参考信号，这个参考信号可以有不同的选择。比如在LTE系统当中，公共参考信号CRS可以作为参考信号的选择。在一些系统里面，也可以选择小区的广播信道或者同步信道作为参考信号。
终端对参考信号的接收强度RSRP，一般选择为对参考信号的接收功率，单位一般采用dBm。因为参考信号的发射功率是恒定的，因此终端越靠近小区边缘，接收到的RSRP就越小，因此可以把RSRP作为终端在小区当中的位置的表征。因为上行和下行在大尺度衰落上具有相关性，因此这种方法在上下都适用，但是在具体的数值上可能有所不同。
为每个子资源组设置一个RSRP门限，这个RSRP门限，在地理上对应围绕基站天线的一条曲线，该曲线包围的区域就是该子资源组的覆盖范围。功率密度上限比较高的子资源组，其覆盖范围也比较大，在覆盖的远端终端接收的RSRP比较小，所以应该设置比较小的RSRP门限。
对于不同的终端，其接收或者发射的处理能力有可能不同，因此可以在终端测量的RSRP的基础上，另外设置一个偏置量，一般用dB表示。用该偏置量对终端的RSRP进行修正后，再与子资源组的RSRP门限去比较。对于处理能力强的终端，可以把RSRP向增大的方向去修正，从而使得该终端可以在更大的区域内使用一个子资源组；对处理能力弱的终端，可以把RSRP向减小的方向去修正，从而使得该终端使用该资源组的区域减小。如果不对RSRP进行修正，相当于RSRP偏置量为0dB，是一个特列。
RSRP偏置量可以作为终端的一个参数存储在手机当中，当接入到一个小区的时候将该参数报告给基站。如果终端不报告RSRP偏置量，基站可缺省地设置为0dB。基站在认为有必要的时候，可以修改终端的RSRP偏置量。
对每一个需要通信的终端，建立覆盖它的所有的子资源组列表，列表当中的资源是可以分配给这个终端的，而不在此列表当中的资源不能分配给此终端。子资源组列表可以通过用终端修正后的RSRP与每个子资源组的 RSRP门限比较来建立。
由于每个子资源组的功率密度上限是基本不变的，它们的RSRP门限也基本不变，因此可以用排序的方法比较快速的建立覆盖一个终端的子资源组列表。比如系统共有6个子资源组，它们的RSRP门限从小到大排列为：
子资源组序号 1 3 6 5 4 2
RSRP门限(dBm) -100 -90 -80 -70 -60 -50
得到这个序列后，如果一个终端的RSRP为-68dBm，在RSRP偏置量为0dB的情况下，把序列当中所有RSRP门限比-68dBm小的子资源组都添加到该终端的子资源组列表，也就是子资源组1、3、6、5。
如果该终端设置了一个-3dB的RSRP偏置量，也就是修正后的终端的RSRP为-71dBm，则覆盖该终端的子资源组列表为1、3、6；如果该终端的门限偏置为10dB，则修正后的RSRP为-58dBm，那么覆盖该终端的子资源组列表为1、3、6、5、4。
也可以把RSRP门限从大到小排序，做法是类似的。
在移动通信系统当中，终端可能是移动的，覆盖它的子资源组列表也会变化。因此终端可以周期性地测量RSRP，并且报告给基站，基站根据终端的RSRP测量报告更新覆盖此终端的子资源组列表。终端报告RSRP的周期可以视情况而定。比如，如果终端的移动速度比较快，就采用比较短的报告周期，反之，如果终端的移动速度比较慢，采用比较长的报告周期。
在资源的分配上，终端可以使用覆盖该终端的子资源组，不能使用不覆盖该终端的子资源组。这个原则只是一个功能性原则，为了使系统达到比较优良的性能，特别是在高负载的情况下达到比较好的性能，可以采用如下的资源分配方法：
为每个参与资源分配的终端建立覆盖该终端的子资源组列表；对每个需要发送数据的用户，首先在覆盖其终端的具有最小覆盖范围的子资源组当中分配资源；如果资源不够，则在具有第二最小覆盖范围的子资源组当中分配资源，依次类推；如果此用户获得了所需的资源，则对下一个用户重复这个过程，直到所有用户获得所需资源，或者没有可分配的资源。
为一个用户分配资源，单从功能的角度来说，在任何一个覆盖其终端的子资源组当中为其分配资源都可以。但是从系统性能的角度来说，如果把大覆盖的子资源组过早地分配给小区中心的终端用户，会出现小区边缘的终端用户没有可分配资源，而小覆盖的子资源组闲置不用的情况。所以优先在覆 盖较小的子资源组当中为终端分配资源，这样使得资源得到最有效的利用。
需要说明的是，分配给每个用户的资源并不局限于时间和频率，也可以是其他的资源，比如说CDMA系统的一个码道。
基于多级软时频复用的资源分配方法可以应用于上行和下行。在应用于上行的时候，资源分配在基站，而发射机在终端，因此基站要把资源分配信息发送给终端，从而使得终端能够在分配的资源上发射用户数据。应用于下行的时候，由于资源分配和数据发送都在基站，因此资源分配信息可以直接用来控制发射机发送用户数据。但是基站也要把资源分配信息发送给终端，使得终端能够在分配的资源上接收数据。
资源分配可以表现为不同的形式。如果通信系统有多个载波，每个子资源组是一个载波，而每个载波都形成一个逻辑小区。在这种情况下，选择一个子资源组就是选择一个逻辑小区，需要通过小区选择重选或者切换过程接入该逻辑小区，然后获得所需要的资源。而在LTE这样的宽带OFDM系统当中，多个用户共同使用一条共享信道，在一条共享信道上就可以划分出多个子资源组，资源分配通过调度来实现。
发射机需要知道PDM信息，从而控制在所有子资源组上的实际发射功率密度不超过相应的功率密度上限。在下行，PDM由基站设置，直接通知发射机就可以了。在上行，PDM也是由基站设置，需要用某种方式通知小区内的终端。由于PDM信息是小区的配置参数，因此作为一个系统消息广播出来是比较适合的，小区内的所有终端都可以接收到。这个系统消息，在3GPP协议体系里面可以封装成为一个RRC系统消息。
比如，如下的数据结构可以表示PDM信息，包括以下字段：
字段1：表示子资源组的数量。
字段2：每个子资源组的资源范围，连续资源的情况可以用起始/结尾的方式表达，非连续资源的情况可以用多个起始/结尾的方法表达；
字段3：最高的功率密度上限，作为基准值；
字段4：每个子资源组的功率密度上限相对于最高的功率密度上限的增益，用dB表达；
每个字段都用一定数量的bit来表示多种取值。比如对于字段1，如果用2个bit表示，可以表示4种子资源组数量：
00 1
01 2
10 4
11 8
这些取值列表可以在协议当中事先规定好。其他的字段也是采用类似的处理方法。
在一些情况下，基站可以修改终端的RSRP偏置量。比如在某一个子资源组上，由于各种原因，功率控制指令经常试图使发射机的功率密度超出设定的功率密度上限，则可以减小终端的RSRP偏置量，使得该子资源组从覆盖该终端的子资源组中去掉，从而切换到功率密度门限更高的子资源组上去。相反，如果一个终端实际的发射功率密度一直比覆盖最小的子资源组的功率密度上限小很多，则可以增加该终端的RSRP偏置，使得功率门限更小的子资源组添加到覆盖该终端的子资源组列表，从而切换到功率密度门限更小的子资源组上去。还有一种情况是，终端离基站比较远，并且有较高的数据速率要求，按照其当前的RSRP偏置量，把所有覆盖它的资源都分配给它仍然无法满足其要求。如果这个终端的优先级很高，基站决定分配给它更多的资源，就可以增加其RSRP偏置量，使得覆盖它的子资源组列表当中有更多的资源。
虽然本发明所揭露的实施方式如上，但所述的内容只是为了便于理解本发明而采用的实施方式，并非用以限定本发明。任何本发明所属技术领域内的技术人员，在不脱离本发明所揭露的精神和范围的前提下，可以在实施的形式上及细节上作任何的修改与变化，但本发明的专利保护范围，仍须以所附的权利要求书所界定的范围为准。

Claims (17)

  1. 一种无线通信系统的资源复用方法，所述无线通信系统至少包含两个相邻小区Ci(i＝1，2)，使用的时频资源记为S，将所述时频资源S划分成至少两个资源单元，每个所述资源单元是一个时间-频率资源块，允许针对各个资源单元单独地设置发射功率密度，其特征是：
    a)把所述时频资源S划分成N个互不重叠的资源组，记为RGn(n＝1，2，…，N)，N是大于1的整数；每个所述资源组包括至少两个所述资源单元；
    b)在小区Ci(i＝1，2)，把RGn(n＝1，2，…，N)划分成互不重叠的两部分，其中，针对一部分设置功率密度上限h(i) n，称为RGn的主子资源组；针对另外一部分设置功率密度上限l(i) n，称为RGn的副子资源组，所述主子资源组和所述副子资源组统称为子资源组，各个所述子资源组的功率密度上限满足关系：l(i) 1/h(i) 1＜l(i) 2/h(i) 2＜…＜l(i) N/h(i) N≤1，并且如果N＝2，l(i) 2≠h(i) 2；
    c)所述两个相邻小区Ci(i＝1，2)在每个资源组上的主子资源组均互不重叠。
  2. 如权利要求1所述的方法，其特征是：
    l(i) 1≤l(i) 2≤…≤l(i) N≤h(i) N≤…≤h(i) 2≤h(i) 1，(i＝1，2)。
  3. 如权利要求2所述的方法，其特征是：
    l(i) 1＜a(i)＜b(i)＜h(i) 1(i＝1，2)，其中a(i)和b(i)是h(i) n(n＝2，3，…，N)和l(i) n(n＝2，3，…，N)当中任意不同的两个。
  4. 如权利要求2或3所述的方法，其特征是：
    在每个小区，为各个子资源组分别确定一个覆盖范围，为具有较高的功率密度上限的子资源组设置较大的覆盖范围。
  5. 如权利要求4所述的方法，其特征是：
    基站持续地发射一个功率恒定的参考信号，终端对所述参考信号的接收强度记为RSRP；为各个子资源组分别确定一个RSRP门限；对功率密度上限较高的子资源组设置较低的RSRP门限，对功率密度上限较低的子资源组设置较高的RSRP门限。
  6. 如权利要求5所述的方法，其特征是：
    终端测量RSRP，并且报告给基站；
    为该终端设置一个RSRP偏置量，并用该偏置量修正该终端报告的RSRP， 得到修正后的终端RSRP；
    基站分别将所述修正后的终端RSRP与各个子资源组的RSRP门限比较，将RSRP门限小于等于所述修正后的终端RSRP的子资源组判定为覆盖该终端的子资源组，以建立覆盖该终端的子资源组列表。
  7. 如权利要求6所述的方法，其特征是：
    基站对所有的子资源组根据其RSRP门限大小排成一个序列；
    把序列当中RSRP门限小于等于该终端修正后的RSRP的所有子资源组添加至覆盖该终端的子资源组列表。
  8. 如权利要求6或7所述的方法，其特征是：
    终端周期性地测量RSRP，并且报告给基站；
    基站根据该终端的RSRP测量报告更新覆盖此终端的子资源组列表。
  9. 如权利要求6或7所述的方法，其特征是：
    终端使用所述子资源组列表中的子资源组，不使用不在所述子资源组列表中的子资源组。
  10. 如权利要求6或7所述的方法，其特征是：
    为每个参与资源分配的终端建立覆盖该终端的子资源组列表；
    对每个需要发送数据的用户，首先在覆盖其终端的具有最小覆盖范围的子资源组当中分配资源；
    如果资源不够，则在具有第二最小覆盖范围的子资源组当中分配资源，依次类推；
    如果此用户获得了所需的资源，则对下一个用户重复这个过程，直到所有用户获得所需资源，或者没有可分配的资源。
  11. 如权利要求2或3所述的方法，其特征是：
    在C1和C2当中的至少一个小区，至少两个主子资源组的资源序号相连。
  12. 如权利要求2或3所述的方法，其特征是：
    应用于上行时，基站将PDM信息在其形成的小区内广播。
  13. 一种基站设备，其特征是，包含以下模块：
    (1)发射模块：持续地发射一个功率恒定的参考信号；
    (2)接收模块：接收终端发来的RSRP和RSRP偏置量；
    (3)PDM设置模块：把时频资源S划分成N个不相互重叠的资源组，记为RGn(n＝1，2，…，N)，N是大于1的整数，每个资源组包括至少两个资源单元；把RGn(n＝1，2，…，N)划分成互不重叠的两部分， 其中一部分设置功率密度上限hn，称为RGn的主子资源组；另外一部分设置功率密度上限ln，称为RGn的副子资源组；所述主子资源组和所述副子资源组统称为子资源组，各个子资源组的功率密度上限满足关系：l1≤l2≤…≤lN≤hN≤…≤h2≤h1，l(i) 1/h(i) 1＜l(i) 2/h(i) 2＜…＜l(i) N/h(i) N≤1，并且如果N＝2，l(i) 2≠h(i) 2；
    (4)覆盖门限生成模块：为每个子资源组确定一个RSRP门限；对功率密度上限较高的子资源组设置较低的RSRP门限，对功率密度上限较低的子资源组设置较高的RSRP门限；
    (5)终端覆盖子资源组列表生成模块：针对各个终端，根据该终端发来的RSRP偏置量来修正所述终端发来的RSRP，得到修正后的RSRP，把所述修正后的RSRP分别与各个子资源组的RSRP门限分别进行比较，将RSRP门限小于等于所述修正后的终端RSRP的子资源组判定为覆盖该终端的子资源组，以建立覆盖该终端的子资源组列表。
  14. 如权利要求13所述的基站设备，其特征是，所述基站设备应用于下行，还包括：
    资源分配模块：对每个需要发送数据的终端，首先在覆盖该终端的具有最小覆盖的子资源组当中分配资源，如果资源不够，则在第二最小覆盖的子资源组当中分配资源，依次类推；如果此该终端获得了所需的资源，则对下一个终端重复这个过程，直到所有终端获得了所需资源，或者没有可分配的资源；其中，
    所述发射模块进一步用于：把所述资源分配模块确定的资源分配信息发送给终端，根据所述资源分配信息给用户数据安排资源，发射用户数据，以及，进行控制使得发射机在各个子资源组上的发射功率密度均不超过各个子资源组各自对应的功率密度上限。
  15. 如权利要求13所述的基站设备，其特征是，所述基站设备应用于上行，还包括：
    资源分配模块：对每个需要发送数据的终端，首先在覆盖该终端的具有最小覆盖的子资源组当中分配资源，如果资源不够，则在第二最小覆盖的子资源组当中分配资源，依次类推；如果该终端获得了所需的资源，则对下一个终端重复这个过程，直到所有终端获得了所需资源，或者没有可分配的资源；其中，
    所述发射模块进一步用于：将PDM信息在小区内广播，把所述资源分配模块确定的资源分配信息发送给终端。
  16. 一种终端设备，其特征是，包括如下模块：
    (1)接收模块：接收基站发射的参考信号，发送给测量模块，接收基站广播的PDM信息和资源分配信息，并发送给发射模块；
    (2)测量模块：测量RSRP，并形成RSRP测量报告，所述RSRP测量报告包括所测量的终端RSRP；
    (3)发射模块：向基站发送所述RSRP测量报告和RSRP偏置量；根据所述资源分配信息为用户数据分配资源，发射用户数据，进行控制使得发射机在各个子资源组上的发射功率密度均不超过各个子资源组各自对应的功率密度上限。
  17. 一种无线通信系统，其特征是：
    至少包含形成两个相邻的小区的两个如权利要求13、14或15所述的基站设备；其中，
    所述两个相邻小区在每个资源组上的主子资源组均互不重叠。
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