WO2011124013A1 - 执行小区选择的方法和装置 - Google Patents

执行小区选择的方法和装置 Download PDF

Info

Publication number
WO2011124013A1
WO2011124013A1 PCT/CN2010/071563 CN2010071563W WO2011124013A1 WO 2011124013 A1 WO2011124013 A1 WO 2011124013A1 CN 2010071563 W CN2010071563 W CN 2010071563W WO 2011124013 A1 WO2011124013 A1 WO 2011124013A1
Authority
WO
WIPO (PCT)
Prior art keywords
base station
low power
user equipment
macro
cell
Prior art date
Application number
PCT/CN2010/071563
Other languages
English (en)
French (fr)
Inventor
杨峰
刘轶铭
徐斌阳
Original Assignee
上海贝尔股份有限公司
阿尔卡特朗讯
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 上海贝尔股份有限公司, 阿尔卡特朗讯 filed Critical 上海贝尔股份有限公司
Priority to CN201080064959.1A priority Critical patent/CN102823300B/zh
Priority to PCT/CN2010/071563 priority patent/WO2011124013A1/zh
Publication of WO2011124013A1 publication Critical patent/WO2011124013A1/zh

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/20—Selecting an access point
    • 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

  • This invention relates generally to wireless communications, and more particularly to a method and apparatus for performing cell selection in a heterogeneous network. Background technique
  • LTE technology is one of the cutting-edge technologies in the field of wireless technology.
  • a base station in an LTE network is generally referred to as an evolved Node B, abbreviated as an eNB.
  • eNBs typically have high power, wide coverage, and high cost.
  • it is generally supported to deploy one or more low-cost low-power base stations, such as micro eNBs, in the coverage of conventional eNBs ( Pico), home eNB (Femto) or relay station, which supports heterogeneous deployment.
  • a conventional eNB is often referred to as a "macro" relative to a low-power eNB.
  • macro also known as macro base station or macro eNB.
  • the coverage of a macro eNB is often referred to as a macro cell.
  • a low power eNB is often referred to as a "micro" relative to a conventional eNB, also known as a micro base station or The coverage of the low eNB is usually referred to as a micro cell.
  • the base station and the cell are corresponding.
  • the user equipment performs cell selection, that is, selects the base station corresponding to the cell as its serving base station. In other words, Selecting the cell to be connected, "selecting the base station to be associated", and “selecting the serving base station” have similar meanings.
  • the criteria for performing cell selection is typically to have the user equipment UE connect to the cell with the highest downlink received power.
  • the transmit power of the macro eNB is typically about 43 dBm
  • the transmit power of Pico is typically in the range of 23 dBm - 30 dBm
  • the transmit power of Femto is typically less than 23 dBm. It can be seen that the transmission powers of the macro eNB and the low power eNB differ by more than 10 dBm, and there is a serious imbalance.
  • the probability that the UE selects to associate with the low power eNB is small. This is contrary to some of the original intentions of deploying low-power eNBs. For example, cannot be achieved It is initially expected that the low-power eNB shares part of the traffic load and cannot obtain the cell splitting gain. Therefore, there is a need to define a new cell selection criterion to enable more user equipment to be associated with a low power base station while still maintaining systemic ⁇ fi ⁇ b.
  • the cell selection criterion can be expressed as the following formula (1), which does not select the serving base station according to the maximum RSRP, but introduces the amount of expansion ⁇ :
  • the Cell ID is the selected cell identification number, i represents the candidate cell identifier, and each candidate cell i corresponds to one base station.
  • RSRP Reference Signal Receiving Power
  • Ai is the amount of expansion applied to the cell i, and the amount of expansion ⁇ is usually used for the micro cell. If the cell i is a macro cell, the ⁇ is set to zero.
  • the RSRP of the low power eNB (corresponding to the micro cell) has a positive offset, which increases the probability that the user equipment selects the low power eNB as its serving base station.
  • more user equipments can be associated with low-power eNBs and get cell splits
  • the above range expansion technique has drawbacks.
  • the amount of expansion ⁇ of each microcell is constant. This amount of expansion ⁇ may be suitable for a certain situation, but it cannot be adapted to different situations. If the amount of expansion is not set properly, it will degrade the performance of the system. For example, when the setting is too large, too many user equipments are associated with the low power eNB. However, the received power from the macro eNB is much larger than the received power from the low power eNB, and the user equipment could have chosen the macro eNB to get a better service. However, when the ⁇ setting is too large, the user equipment is forced to associate with the low power eNB, resulting in a decrease in overall performance. System level simulations have demonstrated this performance degradation. Therefore, the range extension technique using the constant spread amount does not well solve the problems in the above cell selection. Summary of the invention
  • a method for performing cell selection in a heterogeneous network comprising a macro base station and at least one low power base station, each base station corresponding to a respective cell, the method comprising : measuring downlink received power of the macro base station and the low power base station, and using a variable offset to perform range extension on the downlink received power of the low power base station, based on the downlink received power and range extension of the macro base station
  • the downlink received power of the low power base station is selected to select the base station to which the user equipment is to be associated.
  • variable offset is adaptively adjusted in accordance with one or more factors.
  • the variable offset may be adaptively adjusted according to at least one of the following factors: a difference between downlink received power of the macro base station and the low power base station; a traffic load of the macro base station; a service of the low power base station Load; and the speed of movement of the user equipment.
  • an apparatus for performing cell selection in a heterogeneous network comprising a macro base station and at least one low power base station, each base station corresponding to a respective cell
  • the apparatus comprising a measurement module, configured to measure a downlink received power of the macro base station and/or the low power base station, and a range expansion module, configured to expand a downlink receive power of the low power base station by using a variable offset,
  • a selection module configured to select, according to a downlink received power of the macro base station and a downlink received power of the range extended low power base station, the base station to which the user equipment is to be associated.
  • the apparatus further comprises an adaptive adjustment module for adaptively adjusting said variable offset based on one or more factors.
  • a user equipment comprising a device according to the second aspect of the invention.
  • FIG. 1 shows a schematic diagram of an example of a heterogeneous network 100 in which the present invention can be applied;
  • FIG. 2 shows a flow diagram of a process 200 of performing cell selection in accordance with an embodiment of the present invention
  • FIG. 3 shows a schematic block diagram of an apparatus 300 for performing cell selection in accordance with an embodiment of the present invention.
  • FIG. 1 shows a schematic diagram of an example of a heterogeneous network 100 in which LTE of the present invention can be applied.
  • One or more macro base stations are deployed in the network 100.
  • One or more low power eNBs are also deployed within the coverage (macro cell) of at least one macro base station, which may be a relay, a pico eNB (pico), or a home eNB (Femto).
  • This type of deployment is referred to as a heterogeneous deployment, so network 100 is also referred to as a heterogeneous network.
  • low power base stations are not required to be deployed within the coverage of all macro base stations in a heterogeneous network.
  • only one macro eNB 101 is shown in FIG.
  • a relay station eNB 102 a micro eNB (pico) 103, and a home eNB (femo) 104 deployed within the coverage of the macro eNB 101.
  • the coverage of the eNBs 101, 102, 103, and 104 is labeled as Cell 1, Cell 2, Cell 3, and Cell 4, respectively, where Cell 1 is a macro cell and Cell 2 - 4 is an i.
  • a plurality of user equipments are also included, for example, the UE 201, the UE 202, and the UE 203 are shown in FIG.
  • User equipment UE 201, UE 202, UE 203 may be a mobile telephone, a portable computer or personal data assistant supporting wireless communication, and/or other devices that support wireless communication. These user devices need to get services.
  • the base station is required to provide services to it. Therefore, the user equipment needs to perform cell selection to select a base station for association.
  • the associated base station is referred to as the serving base station of the user equipment. It should be understood by those skilled in the art that the user equipment needs to perform cell selection when it is powered on, and also needs to reselect the cell selection when the environment changes (sometimes also refers to cell selection in this case as cell reselection) to reselect. Choose a more suitable service base station. Note that the cell selection mentioned in this application includes cell reselection.
  • network 100 is merely illustrative and may be any heterogeneous network including macro cells and micro cells.
  • the present invention is not limited to the LTE technology, but can be applied to other technologies that support heterogeneity.
  • all UEs 201, 202, and 203 will selectively connect to the macro.
  • eNB 101 0 the low power base stations eNB 201, 202, and 203 cannot share the traffic load, and the network 100 cannot obtain the cell splitting gain.
  • UE 202 is located in the vicinity of eNB 104 within the coverage of eNB 101.
  • the UE 202 should read the association to the eNB 104. Since the transmit power of the macro eNB 101 is much larger than the transmit power of the eNB 104, and the UE 202 is located on the side close to the eNB 101 with respect to the eNB 104, the downlink RSRP of the eNB 101 received by the UE 202! It is much larger than the downlink RSRP 4 of the eNB 104.
  • the ⁇ expansion amount ⁇ 4 may not be suitable for other user equipment. For example, it is set too large for the cell selection of the UE 203 such that the UE 203 cannot select a suitable cell.
  • the UE 203 is located in micro cell 4 At the edge, the transmit power of the eNB 104 is much smaller than the transmit power of the eNB 101, so the downlink RSRP' 4 of the micro cell 4 at the UE 203 is much smaller than the downlink RSRP of the macro cell 1.
  • the UE 203 is notably associated with eNB 101.
  • the measured downlink RSRP' 4 and RSRP' at the UE 203 also satisfy RSRP ' 4 + A 4 > RSRP ', so that the UE 203 adversely selects to connect to the eNB 104.
  • UE 203 is not able to get good service, which reduces system performance.
  • the spreading amount of the cell 4 is set to a lower value so that the UE 203 does not choose to connect to the eNB 104, which in turn may cause the UE 202 to no longer connect to the eNB 104, this is also undesirable.
  • the present invention provides a cell selection mechanism suitable for use in a heterogeneous network 100 that uses a variable offset to spread the microcell.
  • the offset amount ⁇ ( x ) can be adaptively adjusted according to various factors X considered.
  • the offset ⁇ ( Xj ) is adaptively adjusted by factors such as the moving speed of the user equipment, and j, where j represents an index of various factors.
  • the cell selection mechanism of the present invention can be schematically represented, for example, by the following formula (2):
  • Cell ID argmaxlRSRP,. + ⁇ ( ) ⁇ ( 2 ) where Ai ( ⁇ ) can be dynamically adjusted according to different factors.
  • the present invention not only considers the downlink reception power level, but also considers load balancing, fairness, switching frequency, and the like.
  • the present invention extends the range of micro cells by using adaptively adjusted offsets, and the user equipment can select the best serving cell, thereby optimizing the overall performance of the network.
  • the present invention overcomes the problems of the prior art and enables more user equipment to be associated with low power base stations while still maintaining system performance.
  • the user equipment UE 202 is mainly taken as an example for description.
  • FIG. 2 illustrates a process of performing cell selection in accordance with an embodiment of the present invention.
  • Flow chart of 200 illustrates a process of performing cell selection in accordance with an embodiment of the present invention.
  • the user equipment may periodically perform the cell selection procedure of the present invention to select a more suitable serving base station.
  • the base station may also instruct the user equipment to perform cell reselection, and the user equipment may perform the present invention in response to the indication of the base station. The cell selection process.
  • the user equipment e.g., UE 202
  • the user equipment typically only measures the downlink reference signal received power RSRP of each base station.
  • UE 202 measures downlink RSRP 2 - RSRP 4 of downlink RSRP microcell 2 - 4 of macro cell 1.
  • RSRQ Reference Signal Receiving Quality
  • RSSK Received Signal Strength Indicator
  • received signal strength indicator the user equipment also measures the RSSI.
  • the user equipment does not need to measure the downlink received power level of all base stations.
  • a threshold may be set, and only the cell corresponding to the downlink received power level above the threshold may be considered as a candidate for the serving cell. The downlink received power below the threshold may not be measured.
  • UE 202 is outside the coverage of eNB 102 and eNB 103, and the received downlink reception power levels of cells 2 and 3 are very small, so RSRP 2 and RSRP 3 may not be measured. Thus, UE 202 may only consider cells 1 and 4 when performing the following steps.
  • the user equipment Since not only the received power level is considered in the present invention, other factors can be considered. In different considerations, in order to obtain the physical parameters corresponding to the factors considered, the user equipment needs to perform other measurements or receive additional information required from the base station. For convenience of explanation, in the example shown in FIG. 2, not only the received power level but also the difference between the received power levels, the load balance between the base stations, and the cell switching frequency are considered. . In order to obtain relevant information, the user equipment, e.g. UE 202, optionally performs a step - S204, in which UE 202 receives a traffic load status indication of the base station.
  • a step - S204 in which UE 202 receives a traffic load status indication of the base station.
  • the UE 202 may correspondingly receive a traffic load indication// and/or / 4 of the corresponding eNB (eNB 101 or eNB 104, or both).
  • the traffic load status indication of the base station may be periodically transmitted by the base station to all user equipments within its coverage through the broadcast channel.
  • the base station may send a forcible traffic load status indication on the user equipment dedicated channel in response to the request of the user equipment.
  • the user equipment e.g., UE 202
  • step S206 in which UE 202 measures its own speed of movement.
  • the moving speed of the user equipment is related to the switching frequency.
  • the moving speed of the user equipment may traverse multiple different cells in a short time (for example, during a call), so that it is possible to frequently perform cell switching and affect the call. the quality of. In this case, unnecessary cell reselection/switching needs to be avoided.
  • steps S204 and S206 are optional and not required.
  • the UE 202 may also consider factors such as location, thereby requiring location measurements, or receiving relevant location information from the base station.
  • step S208 the UE 202 adaptively adjusts the variable offset for the range extension of the low power base station according to different factors.
  • the difference in the received power, the traffic load, and the moving speed of the user equipment are mainly considered. Therefore, the offset of the micro-area i, which is adapted to be adjusted, can be designed as follows:
  • ⁇ ; (/, RSRP, v UE ) C ⁇ w ⁇ , (/) + w 2 A ; (RSRP) + w 3 * ⁇ ⁇ ) ( 3 )
  • C is a constant; is based on the microcell i
  • the offset adjustment component of the traffic load status indication/corresponding to the low power base station eNB, A (RSRP) is based on the offset adjustment of the downlink RSRP difference between the micro cell i and the macro cell corresponding to the macro eNB
  • the traffic load status on the low power base station eNB (e.g., eNB 104) on which the ' (/ ) is based may be simply represented by a traffic load status indication (e.g., / 4 ) on the low power eNB received in step S204.
  • a traffic load status indication e.g., / 4
  • the service on the low power base station eNB is negative
  • the load status/ may be an indication of the relative traffic load status relative to the macro base station, for example 4 /.
  • the adjustment component "' (/) can be used to equalize the traffic load between the low power base station and the macro base station. When the traffic load on the low power base station corresponding to the micro cell i is already heavy, " ⁇ ) becomes smaller, To reduce the number of user equipment associated with the microcell i.
  • the adjusted component ⁇ ' can be used to compensate for the downlink received power difference between the macro base station and the low power base station.
  • the downlink received power difference between the macro base station and the low power base station is small, it may indicate that the user equipment is at the edge of the macro cell and is close to the low power base station (i.e., near the center of the micro cell). In this case, it is more effective to select a low power base station as the serving base station.
  • A RSRP
  • the downlink received power difference between the macro base station and the low power base station is large, that is, the downlink received power of the macro base station is much larger than the downlink received power of the low power base station, the macro base station is selected as the serving base station. More suitable. For this reason, A '( RSRP ) can be set to be smaller. In this way, the downlink received power difference of the macro base station and the low power base station can be compensated during cell selection. It should be understood that A '( RSRP ) can be designed in a variety of ways, and all functions that conform to the above logical relationships can be used to represent A '( RSRP ).
  • A may be an inverse proportional function of the RSRP difference
  • R SRP may also be a function that conforms to the above logical relationship, such as a temple, etc., which is fitted according to test and/or simulation results.
  • the adjustment component ⁇ ) can be used to control the frequency of execution of the cell selection. If the speed V UE of the user equipment is large, frequent cell selection/handover may be caused. This increases the signaling overhead and the quality of service QoS obtained by the user equipment may also be adversely affected. In order to avoid frequent cell selection/handover, the adjustment component may be set to be smaller as the speed V UE of the user equipment becomes larger. Thus, by designing the appropriate adjustment component ⁇ ), The user equipment does not frequently switch between the macro base station and the low power base station. It should be understood that D can be designed in a variety of ways, and all functions that conform to the above logical relationships can be used to represent D. For example, D may be an inverse proportional function of the speed V UE of the user equipment, and D may also be a function that fits the above logical relationship according to the test and/or simulation result, and so on.
  • Each weighting factor W" can be used to adjust the effect of the corresponding adjustment component on the total offset to better achieve the desired design goal.
  • the adaptively adjusted offset design of the micro-region i described in the above formula (3) is for illustrative purposes only and is not intended to limit the invention to the particular form. Based on the above description, those skilled in the art can consider more or less factors to adaptively adjust the offset ⁇ (x) for the range extension of the microcell.
  • step S210 the downlink received power of the micro cell i is range-expanded using the variable offset Ai (X).
  • the macro cell can be regarded as a range extension with an offset of 0.
  • the range-expanded downlink received power can be calculated for each candidate cell i, for example, RSRP'i-RSRPi+A (x).
  • the base station to which the user equipment is to be associated may be selected based on the downlink received power of the macro base station and the downlink received power of the range-extended micro-cell (corresponding to the low-power base station).
  • UE 202 primarily considers candidate cells 1 and 4, as previously mentioned in step S202.
  • the UE 202 has obtained the downlink RSRP of the macro cell 1, and the downlink RSRP 4 + A 4 (x) of the micro cell 4.
  • the UE 202 may select a cell to be associated from the candidate cells (i.e., cells 1 and 4) according to formula (2).
  • the UE 202 will select the RSRP, and the corresponding cell 1 is used as the serving cell, that is, it is selected to be associated with the macro base station 101.
  • the selected UE202 RS P 4 corresponding to the cell as the serving cell 4, i.e., to select the associated macro base station 104 to the low power.
  • Gao as there are more than two candidate cells, the user equipment according to the The cell corresponding to the maximum value in ( ⁇ ) is associated. At this point, Process 200 ends.
  • the user equipment can be connected to the selected cell, which can be implemented in a variety of existing or future developed technologies. Since it is not related to the gist of the present invention, it will not be described herein.
  • FIG. 3 shows a schematic block diagram of an apparatus 300 for performing cell selection in accordance with an embodiment of the present invention.
  • the cell selection apparatus of the present invention includes: a power measurement module 302, configured to measure downlink receiving power of a macro base station and/or a low power base station; and a range expansion module 310, configured to use a variable offset to the low power base station The downlink received power is range-expanded; and the selecting module 312 is configured to select the base station to which the user equipment is to be associated based on the downlink received power of the macro base station and the downlink received power of the range-expanded low-power base station .
  • Power measurement module 302 is typically configured to measure the RSRP of the downlink. In addition to using RSRP to characterize downlink received power in the present invention, other parameters well known in the art can be selected to characterize downlink received power. Thus, power measurement module 302 is also configured to measure other related power parameters. For example, as an alternative to RSRP, RSRQ can be used to characterize the downlink received power, which is the ratio of RSRP to RSSI. In this case, power measurement module 302 is also configured to measure the RSSI.
  • the range extension module 310 uses a variable offset according to the present invention to range extend the downlink received power of the low power base station. If RSRP is used to characterize the downlink received power, the range-expanded can be calculated for each candidate cell i separately ( x ) ensemble If RSRP is used to characterize the downlink received power, the range-expanded
  • RSRQ' RS Qi+ ⁇ ; ( ⁇ ) 0 does not need to be extended for the case where the candidate cell is a macro cell, but a range extension with an offset of 0 can be similarly performed.
  • the macro cell and the micro cell can be treated uniformly in the selection module 312.
  • the selection module 312 typically selects the one of the candidate cells with the largest range-widened downlink received power (eg, the largest RSRPi, or the largest RSRQ'i) from the candidate cells.
  • the district serves as its serving community. If the macro cell is regarded as having undergone a range extension with an offset of 0, the selection module 312 may uniformly sort all the candidate cells in descending order based on the range-expanded downlink received power, and select the first order. Community. Or the selecting module 312 can distinguish the macro cell and the micro cell, first sort the candidate micro cell and the macro cell respectively, and then compare the downlink receiving power of the first micro cell and the first macro cell to select The larger of the two corresponds to the cell. It should be understood that any sorting mechanism known can be used in the present invention and will not be described herein.
  • apparatus 300 further includes a receiving module 304.
  • the receiving module 304 can be configured to receive indications and/or information of the base station.
  • the device 300 may perform cell selection periodically or in response to an indication by the base station. In the latter case, receiving device 304 needs to receive an indication from the base station to perform cell selection.
  • the receiving module 304 is further configurable to receive other information transmitted by the base station to the user equipment, such as various parameters that adjust the variable offset for range extension.
  • the base station can transmit this information over the broadcast channel or in response to the user equipment request via the user equipment dedicated channel.
  • apparatus 300 also includes other measurement modules, such as measuring various parameters required to adjust the variable offset for range expansion.
  • device 300 can include a speed measurement module 306 for measuring the speed of movement of the user equipment.
  • the apparatus 300 further includes an adaptive adjustment module 308 that adaptively adjusts the range extension according to the measurement threshold of the power measurement module 302 and/or other measurement modules, and/or various parameters received by the receiving module. Offset.
  • the variable offset can be dynamically adjusted based on various factors such as differences in received power levels, traffic load conditions of the base station, and moving speed of the user equipment. It will not be described in detail here.
  • the modules shown by device 300 are merely illustrative and may include more modules.
  • the device 300 may further include a sending module for transmitting a user request; and/or a computing module, and the like.
  • device 300 may omit one or more of the illustrated modules.
  • module 306 may be omitted when there is no need to consider the speed of the user equipment.
  • the apparatus 300 for performing cell selection of the present invention may be located within a user equipment as part of the user equipment. Device 300 can also be located in other devices that are in communication with the user device.
  • the mechanism for performing cell selection of the present invention not only considers the received power level but also considers load balancing between base stations, cell switching frequency, and the like by designing an adaptively adjusted offset. It can be ensured that the user equipment is associated with the best cell. While connecting more user equipment to the low-power base station, the QoS of the service is ensured, and the overall throughput of the network is increased.
  • the present invention has been described above in connection with a heterogeneous environment of LTE. It should be understood that the present invention is also applicable to other heterogeneous environments, such as WiMax and the like.
  • the embodiments described above are illustrative and not restrictive.
  • the various steps exemplified are not indispensable, and the order is not limiting. For example, depending on the actual needs, you can customize the method of cell execution, adding or deleting certain steps. Alternatively, the above steps may be performed in a different order, or some steps may be performed in parallel.
  • the devices and user equipment exemplified for performing cell selection may also include more or fewer units.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Description

执行小区选择的方法和装置 技术领域
本发明一般地涉及无线通信， 尤其涉及在异构网络中执行小区选 择的方法和装置。 背景技术
目前， LTE技术是无线技术领域的前沿技术之一。 LTE网络中的 基站一般称为演进型节点 B， 简称为 eNB。 常规 eNB通常功率大， 覆 盖范围广， 成本也高。 在 LTE的部署中， 为了增加容量、 实现更好的 用户体验以及提高室内覆盖率等等， 通常还支持在常规 eNB的覆盖 范围中部署一个或多个低成本的低功率基站， 例如微型 eNB ( pico )、 家庭 eNB ( Femto )或者中继站 （ Relay station ), 也即支持异构部署。 在异构部署中， 常规 eNB相对于低功率 eNB而言通常称为 "宏
( macro )" , 也称为宏基站或宏 eNB。 宏 eNB的覆盖范围通常称为宏 小区。 低功率 eNB相对于常规 eNB而言通常称为 "微（micro )" , 也 称为微基站或微 eNB， 低功率 eNB的覆盖范围通常称为微小区。 在 本发明应用的上下文中， 基站和小区是对应的。 用户设备执行小区选 择也就是选择小区对应的基站作为其服务基站。 换言之， "选择要关. 联的小区"、 "选择要关联的基站" 以及 "选择服务基站" 具有类似的 含义。
在现有的系统中， 执行小区选择的标准通常是使用户设备 UE连 接到具有最高下行链路接收功率的小区。 宏 eNB的发射功率和低功 率 eNB的发射功率存在相当大程度的不平衡。 例如， 常规 eNB的发 射功率通常约 43dBm, 而 Pico的发射功率通常是在 23dBm - 30dBm 的范围内容， Femto的发射功率通常小于 23dBm。 可以看出，宏 eNB 和低功率 eNB的发射功率相差 lOdBm以上， 存在严重的不平衡。 所 以， 使用上述现有的小区选择标准， UE选择与低功率 eNB关联的概 率很小。 这与部署低功率 eNB的某些初衷是背离的。 例如不能实现 最初期望的由低功率 eNB分担部分业务负载， 也不能获得小区分裂 ( splitting ) 增益。 因此， 需要定义一种新的小区选择标准来使得更 多的用户设备能够与低功率基站相关联， 同时仍然能够维持系统性 έ fi匕b。
为了使更多的用户设备与低功率 eNB相关联，提出了一种范围扩 展技术。 在该范围扩展技术中， 小区选择标准可以表示为下面的公式 ( 1 ), 其不是根据最大的 RSRP来选择服务基站， 而是引入了扩展量 △:
CellID = argmax{RSRP(. + Δ,.} ( 1 )
i
其中， CellID是被选择的小区标识号， i表示候选小区标识， 每个候选 小区 i对应一个基站。 RSRP ( Reference Signal Receiving Power )是参 考信号接收功率， 其可以表征下行链路接收功率。 RSRPi用于指示小 区 i的下行链路接收功率， 即来自小区 i对应的基站 i的下行链路接 收功率。 Ai是应用于小区 i的扩展量， 扩展量△通常用于微小区， 如 杲小区 i是宏小区， 则谊 Δί设置为零。 在如公式 （ 1 ) 所述的小区选 择标准中， 低功率 eNB (对应于微小区） 的 RSRP具有正的偏移量， 其提高了用户设备选择低功率 eNB作为其服务基站的概率。 于是， 更多的用户设备可以与低功率 eNB关联， 并且获得小区分裂
( splitting ) 增益。
然而， 上述范围扩展技术存在缺陷。 在上述范围扩展技术中， 每 个微小区的扩展量 Δ是常数。 该扩展量△可能适合于某种情形， 但不 能适应不同的情形。 如果该扩展量设置得不合适， 其将降低系统的性 能。 例如， 当 设置过大时， 会有过多的用户设备与低功率 eNB相关 联。 然而， 来自宏 eNB的接收功率远大于来自低功率 eNB的接收功 率， 用户设备本可以选择宏 eNB以获得更好的服务。但是当△设置过 大时， 用户设备被迫选择与低功率 eNB相关联， 导致了总体性能的 下降。 系统级的仿真已经验证了这种性能下降。 因此， 使用常数扩展 量 的范围扩展技术并不能很好地解决上述小区选择中存在的问题。 发明内容
本发明的目的在于提供一种新的小区选择方法和装置， 其能够使 得更多的用户设备与低功率基站相关联， 并且同时仍然能够维持系统 性能。
根据本发明的第一方面， 提供了一种在异构网络中执行小区选择 的方法， 所述异构网絡包括宏基站和至少一个低功率基站， 每个基站 对应各自的小区， 所述方法包括： 测量宏基站和低功率基站的下行链 路接收功率， 使用可变的偏移量来对低功率基站的下行链路接收功率 进行范围扩展， 基于宏基站的下行链路接收功率和经范围扩展的低功 率基站的下行链路接收功率来选择用户设备要关联的基站。
在根据本发明的一个优选实施例中， 根据一个或多种因素自适应 地调整所述可变的偏移量。 优选地， 所述可变的偏移量可以根据以下 因素中的至少一个进行自适应调整： 宏基站和低功率基站的下行链路 接收功率之差； 宏基站的业务负载； 低功率基站的业务负载； 以及用. 户设备的移动速度。
根据本发明的第二方面， 提供了一种在异构网络中执行小区选择 的装置， 所述异构网络包括宏基站和至少一个低功率基站， 每个基站 对应各自的小区， 所述装置包括： 测量模块， 用于测量宏基站和 /或低 功率基站的下行链路接收功率， 范围扩展模块， 用于使用可变的偏移 量来对低功率基站的下行链路接收功率进行范围扩展， 选择模块， 用 于基于宏基站的下行链路接收功率和经范围扩展的低功率基站的下 行链路接收功率来选择所述用户设备要关联的基站。
优选地， 该装置进一步包括自适应调整模块， 用于根据一个或多 种因素自适应地调整所述可变的偏移量。
根据本发明的第三方面， 还提供了一种包括根据本发明的第二方 面的装置的用户设备。 附图说明
通过阅读参照以下附图所作的对本发明的非限制性实施例所作 的详细描述， 本发明的以上及其它特征、 目的和优点将会变得更加明 显：
图 1示出了在其中可以应用本发明的一个异构网络 100的例子的 示意图；
图 2示出了根据本发明的一个具体实施例的执行小区选择的过程 200的流程图； 以及
图 3示出了根据本发明的一个具体实施例的用于执行小区选择的 装置 300的示意性框图。
附图中， 相同或者相似的附图标记代表相同或者相似的部件。 具体实施方式
在下文中， 将参考附图通过示例性实施例对本发明的执行小区选 择的方法、 装置以及用户设备进行详细的描述。 以下实施例以 LTE 无线网络为例进行说明。 所属技术领域的技术人员应当明白， 本发明 并不限于 LTE环境， 而是可以应用于任何支持异构的无线网络。
图 1示出了在其中可以应用本发明的一个 LTE的异构网络 100的 例子的示意图。 网络 100中部署了一个或多个宏基站。 在至少一个宏 基站的覆盖范围 （宏小区） 内还部署了一个或多个低功率 eNB, 所述 低功率 eNB可以是中继站 （ Relay )、 微 eNB ( pico )、 或者家庭 eNB ( Femto )。这种部署称为异构部署，因此网絡 100也被称为异构网络。 应该理解， 并不要求异构网絡中的所有宏基站的覆盖范围内都部署低 功率基站。 为了便于说明， 在图 1 中仅示出了一个宏 eNB 101 , 以及 在宏 eNB 101的覆盖范围内部署的中继站 eNB 102、 微 eNB ( pico ) 103以及家庭 eNB ( femo ) 104。 eNB 101、 102、 103和 104的覆盖范 围分别标为小区 1、 小区 2、 小区 3和小区 4, 其中小区 1是宏小区， 小区 2 - 4是 i 、区。 在网络 100中， 还包括多个用户设备， 例如在 图 1 中示出了 UE 201、 UE 202、 UE 203。 用户设备 UE 201、 UE 202、 UE 203可以是移动电话、 支持无线通信的便携式计算机或个人数据 助理， 和 /或其他支持无线通信的设备。 这些用户设备要获得服务， 需 要基站向其提供服务。 所以用户设备需要执行小区选择， 以选择一个 基站进行关联。 所关联的基站被称为该用户设备的服务基站。 本领域 技术人员应谅理解， 用户设备在开机时需要执行小区选择， 在环境变 化时， 也需要重选执行小区选择（有时也将这种情况下的小区选择称 为小区重选） 以重选选择更合适的服务基站。 注意， 在本申请中提到 的小区选择包括小区重选。
应谅理解， 网络 100仅是示意性的， 其可以是包括宏小区和微小 区的任意异构网络。 本发明也不局限于 LTE技术， 而是可以应用于其 他支持异构的技术。
下面， 首先考虑异构网絡 100中使用常规的小区选择标准（即用 户设备选择连接到具有最高下行链路接收功率的小区）的情况。 因为 宏 eNB 101的发射功率远大于低功率 eNB 102、 103或者 104的发射 功率。 因此， 用户设备， 例如 UE 201、 202或 203, 测量到的 RSRPi ( i = 1 , 2, 3, 4, 分别对应于小区标号 1 - 4 ) 中对应于宏 eNB 101 的下行链路的 RSRP 1将远大于对应于微小区的下行链路的其他 RSRP i ( i = 2, 3 , 4 )。 于是， 所有 UE201、 202和 203都将选择连接到宏. eNB 1010 这种情况下， 低功率基站 eNB 201、 202和 203不能分担业 务负载， 并且网络 100不能获得小区分裂增益。
其次， 考虑异构网络 100使用如上述公式 （ 1 ) 所述的范围扩展 技术的小区选择标准的情况。 如图 1所示， UE 202位于 eNB 101的 覆盖范围内的 eNB 104的附近。优选地，UE 202应读关联到 eNB 104。 鉴于宏 eNB 101的发射功率远大于 eNB 104的发射功率，并且 UE 202 位于相对于 eNB 104的靠近 eNB 101的一侧，所以 UE 202接收的 eNB 101的下行链路 RSRP！比 eNB 104的下行链路 RSRP 4大的多。 这种 情况下，需要给 eNB 104对应的小区 4增加较大的扩展量△ 4(其中△的 下标对应于小区标号）才能使得 UE 202处的 RSRP^ A^RSRP,，从而 使得 UE 202可以选择连接到 eNB 104。 但是， 铉扩展量 ^4对于其他 用户设备可能是不合适的。 例如， 其对于 UE 203的小区选择而言设 置地过大， 使得 UE 203不能选择合适的小区。 UE 203位于微小区 4 的边缘， eNB 104的发射功率又远小于 eNBlOl的发射功率， 所以 UE 203处的微小区 4的下行链路 RSRP'4远小于宏小区 1的下行链路 RSRP 优选地， UE 203应谅关联到 eNB 101。 但是因为扩展量 4 设置地较大， UE 203处的测量的下行链路 RSRP'4和 RSRP',也满足 RSRP'4+A4> RSRP', , 从而 UE 203不利地选择连接到 eNB 104。 UE 203不能够获得良好的服务， 这降低了系统性能。 另一方面， 如果将 小区 4的扩展量设为较低的值，使得 UE 203不会选择连接到 eNB 104, 其又可能使得 UE 202不再连接到 eNB 104, 这同样是不期望的。
因此， 网络 100需要使用一种的小区选择机制以克服上述问题。. 本发明提供了一种适合在异构网络 100中使用的小区选择机制， 其使用可变的偏移量来扩展微小区。 在本发明中， 可以根据考虑的各 种因素 X自适应地调整偏移量 Δ ( x )。 优选地， 在本发明的小区选择 机制中， 可以根据宏基站和低功率基站的下行链路接收功率之差； 用 户设备的位置； 宏基站和 /或低功率基站的业务负载状况； 以及 /或者 用户设备的移动速度等等因素， 自适应地调整偏移量△ ( Xj ) , 其中 j 表示各种因素的索引。 本发明的小区选择机制例如可以通过下面的公 式 （2 ) 示意性地表示：
CellID = argmaxlRSRP,. +Δ ( )} ( 2 ) 其中， Ai ( χ )可以根据不同因素动态地调整。 在该小区选择标准中， 本发明不仅考虑了下行链路接收功率水平， 而且考虑了负载均衡、公 平性、 切换频率， 等等。
一般而言， 本发明通过使用自适应调整的偏移量对微小区进行范 围扩展， 用户设备可以选择最佳的服务小区， 从而使得网絡的整体性 能达到最佳。 换言之， 本发明克服了现有技术存在的问题， 可以使得 更多的用户设备能够与低功率基站相关联， 同时仍然能够维持系统性 能。
下面参考图 2， 详细描述如何执行本发明的小区执行方法。 在下 文的描述中， 主要以用户设备 UE 202为例进行说明。
图 2示出了根据本发明的一个具体实施例的执行小区选择的过程 200的流程图。
因为 LTE移动环境的多变性（例如用户设备可能不时地移动到不 同位置， 或者受到其他用户设备的影响等等）， 用户设备可以定期地 执行本发明的小区选择过程以选择更合适的服务基站。 可选地， 在当 前的服务基站检测到来自用户设备的上行链路的信号低于某个阈值 时， 基站也可以指示用户设备进行小区重选， 于是用户设备可以响应 于基站的指示执行本发明的小区选择过程。
在步骤 S202 , 用户设备例如 UE 202测量各个基站的下行链路接 收功率水平。 用户设备通常仅测量各个基站的下行链路参考信号接收 功率 RSRP。 例如， UE 202测量宏小区 1的下行链路 RSRP 微小区 2 - 4的下行链路 RSRP2 - RSRP4。
应该理解， 在本发明中除了使用 RSRP来表征下行链路接收功率 之外， 还可以选择本领域中熟知的其他参数来表征下行链路接收功 率。 例如， 作为替代， 可以使用 RSRQ(Reference Signal Receiving Quality，参考信号接收质量)来表征下行链路接收功率， 其中 RSRQ是 RSRP和 RSSK Received Signal Strength Indicator,接收信号强度指示） 的比值。 在这种情况下， 步骤 S202中， 用户设备还测量 RSSI。 . . 此外， 应该理解， 用户设备并不需要测量所有的基站的下行链路 接收功率水平。 优选地， 可以设置一个阈值， 仅考虑高于谅阈值的下 行链路接收功率水平所对应的小区可以作为服务小区的候选。对低于 该阈值的下行链路接收功率可以不进行测量。 在图 1所示的例子中， UE 202在 eNB 102和 eNB 103的覆盖范围之外， 接收到的小区 2和 3 的下行链路接收功率水平非常小， 因此可以不测量 RSRP2和 RSRP3。 于是， UE 202在执行下面的步骤时， 可以仅考虑小区 1和 4。
由于在本发明中不仅考虑接收功率水平， 还可以考虑其他因素。 在不同的考虑情形下， 为了获取所考虑的因素对应的物理参数， 用户 设备还需要进行其他测量， 或者从基站接收需要的附加信息。 为了便 于说明， 在图 2所示的例子中， 不仅考虑了接收功率水平， 还考虑了 接收功率水平之间的差异， 基站之间的负载均衡以及小区切换频率。. 为了获得相关的信息， 用户设备例如 UE 202可选地执行步骤 - S204, 在该步骤中 UE 202接收基站的业务负载状态指示。 小区选择 过程 200中可以仅考虑宏小区 1的业务负载状态 ί ι , 或者仅考虑微 小区 4的业务负载状态 /4, 也可以同时考虑两者。 UE 202可以相应地 接收对应的 eNB ( eNB 101或 eNB 104 , 或者两者） 的业务负载状悉 指示 /,和/或 /4。 基站的业务负载状态指示可以由基站定期地通过广播 信道发送给其覆盖范围内的所有用户设备。 可选地， 基站可以响应于 用户设备的请求， 在用户设备专用的信道发送谅业务负载状态指示。
可选地，用户设备例如 UE 202还执行步骤 S206,在该步骤中 UE 202测量其自身的移动速度。 用户设备的移动速度与切换频率相关， 用户设备的移动速度较快时， 其可能短时间内 （例如在一次通话过程 中） 穿越多个不同的小区， 从而有可能频繁地进行小区切换， 影响通 话的质量。 在这种情况下， 需要避免不必要的小区重选 /切换。
应读理解， 步骤 S204和 S206是可选地而非必须的。 作为替代或 补充， UE 202还可以考虑位置等因素， 从而需要进行位置测量， 或 者从基站接收相关的位置信息。
接着， 在步骤 S208中， UE 202根据不同的因素来自适应地调整 用于低功率基站的范围扩展的可变的偏移量。 在实施例中主要考虑接 收功率差异、 业务负载和用户设备的移动速度， 于是微小区 i的自,适 应调整的偏移量可以设计为：
Δ; (/， RSRP, vUE) = C ^ w^ , (/) + w2A; (RSRP) + w3 * β{νυΕ) ( 3 ) 其中， C是常量； 是基于微小区 i对应的低功率基站 eNB上的 业务负载状态指示 /的偏移量调整分量， A(RSRP) 是基于微小区 i与宏 eNB对应的宏小区之间的下行链路 RSRP 差值的偏移量调整分量， D 是基于用户设备的移动速度 vue的偏移量调整分量， 以及 ( j = 1 , 2 , 3 )表示权重系数。
"'(/) 所基于的低功率基站 eNB (例如， eNB 104 ) 上的业务负 载状态 /可以简单地用步骤 S204中接收的低功率 eNB上的业务负载 状态指示（例如 /4 )来表示。 优选地， 该低功率基站 eNB上的业务负 载状态 /可以是相对于宏基站的相对业务负载状态指示，例如是 4/ 。 调整分量 "'(/)可以用于均衡低功率基站与宏基站之间的业务负载。 当 微小区 i对应的低功率基站上的业务负载/已经较重时， "^) 变得较 小， 以减少与微小区 i相关联的用户设备的数目。 当微小区 i对应的 低功率基站上的业务负载 /较轻时， 变得较大， 以增加与微小区 i相关联的用户设备的数目。 以这种方式， 可以均衡宏基站和低功率 基站之间的业务负载。 应谅理解， 可以以各种方式来设计 "' ， 所有 符合上述逻辑关系的函数都可以用于表示 "'(0。 例如" 可以简单地 是业务负载的反比例函数， "' 还可以是根据测试和 /或仿真结杲拟合 得到的符合上述逻辑关系的函数， 等等。
调整分量 Δ' (RSRP)可以用于补偿宏基站和低功率基站的下行链路 接收功率差。 当宏基站和低功率基站的下行链路接收功率差较小时， 其可以表明用户设备处于宏小区的边缘并且靠近低功率基站（即在微 小区的中心附近）。 这种情况下， 选择低功率基站作为服务基站更加 有效。 为此 A(RSRP) 可以被设置为较大， 以提高用户设备与低功率基 站相关联的概率。 另一方面， 如果宏基站和低功率基站的下行链路接 收功率差较大， 也即宏基站的下行链路接收功率远大于低功率基站的 下行链路接收功率， 则选择宏基站作为服务基站更加合适。 为此， A'(RSRP)可被设置为较小。 通过这种方式， 可以在小区选择期间补偿 宏基站和低功率基站的下行链路接收功率差。 应该理解， 可以以各种 方式来设计 A'(RSRP) , 所有符合上述逻辑关系的函数都可以用于表示 A'(RSRP)。 例如 A(RSRP)可以是所述 RSRP差的反比例函数， RSRP)还 可以是根据测试和 /或仿真结果拟合得到的符合上述逻辑关系的函数， 寺等。
调整分量 ^)可以用于控制小区选择的执行频率。如果用户设备 的速度 V UE较大， 则可能引起频繁的小区选择 /切换。 这会增大信令 开销， 并且用户设备获得的服务质量 QoS也可能受到不利影响。 为了 避免频繁的小区选择 /切换， 可以将调整分量 设置为随着用户设 备的速度 V UE变大而较小。 由此， 通过设计的合适的调整分量^ ) , 用户设备不会频繁地在宏基站和低功率基站之间切换。 应该理解， 可 以以各种方式来设计 D , 所有符合上述逻辑关系的函数都可以用 于表示 D。 例如 D可以是用户设备的速度 V UE的反比例函数， D还可以是根据测试和 /或仿真结果拟合得到的符合上述逻辑关系 的函数， 等等。
各个权重系数 W」可以用于调整对应的调整分量对总偏移量的影 响， 从而更好地实现期望的设计目标。
上述公式（ 3 )所述的微小区 i的自适应调整的偏移量设计仅是用 于示例说明的目的而非将本发明限制于该特定形式。 根据上述描述， 本领域技术人员可以考虑更多或者更少的因素来自适应地调整用于 微小区的范围扩展的偏移量△ (x)。
接着， 在步骤 S210中， 使用可变的偏移量 Ai ( X )对微小区 i的 下行链路接收功率进行范围扩展。 尽管对于宏小区不进行范围扩展， 但是可以将宏小区视为进行了偏移量为 0的范围扩展。 于是， 可以分 别针对每个候选小区 i, 计算经范围扩展后的下行链路接收功率， 例 如 RSRP'i-RSRPi+A (x)。
接着， 在步骤 S212中， 可以基于宏基站的下行链路接收功率和 经范围扩展的微小区 （对应于低功率基站）的下行链路接收功率来选 择用户设备要关联的基站。 下面， 继续以 UE 202为例进行说明。 为 了简单起见， UE202主要考虑候选小区 1和 4, 如前面在步骤 S202 中提到的那样。 在步骤 S212之前， UE202已经获得了宏小区 1的下 行链路 RSRP,,以及微小区 4的下行链路 RSRP4+A4( x)。在步骤 S212 中， UE 202可以根据公式 （2) 从候选小区 （即小区 1和 4) 中选择 要关联的小区。如果 RSRP^RSRi^+A^x), 则 UE 202将选择 RSRP, 对应的小区 1作为服务小区， 也即选择关联到宏基站 101。 如杲 RSRPi<RSRP4+A4 ( X ) , 则 UE202将选择 RS P4对应的小区 4作为 服务小区， 也即选择关联到低功率宏基站 104。 如杲存在不止 2个候 选小区， 则用户设备可以根据上 :述公式 （2) 类似地选择经扩展后的
Figure imgf000012_0001
(χ) 中的最大值所对应的小区以进行关联。 至此， 过程 200结束。
此后， 用户设备可以连接到所选择的小区， 这可以各种现有的或 者将来开发的技术来实现。 因为其与本发明的要点无关， 在此不再赘 述。
下面结合图 3对本发明的小区选择装置进行详细说明。
图 3示出了根据本发明的一个具体实施例的用于执行小区选择的 装置 300的示意性框图。
本发明的小区选择装置包括： 功率测量模块 302， 用于测量宏基 站和 /或低功率基站的下行链路接收功率； 范围扩展模块 310, 用于使 用可变的偏移量来对低功率基站的下行链路接收功率进行范围扩展； 以及选择模块 312， 用于基于宏基站的下行链路接收功率和经范围扩 展的低功率基站的下行链路接收功率来选择所述用户设备要关联的 基站。
功率测量模块 302通常被配置为测量下行链路的 RSRP。 在本发 明中除了使用 RSRP来表征下行链路接收功率之外， 还可以选择本领 域中熟知的其他参数来表征下行链路接收功率。 于是， 功率测量模块 302也被配置用于测量其他的相关功率参数。 例如， 作为 RSRP的替 代， 可以使用 RSRQ来表征下行链路接收功率， 其是 RSRP和 RSSI 的比值。 在这种情况下， 功率测量模块 302还被配置用于测量 RSSI。
范围扩展模块 310使用根据本发明的可变的偏移量来对低功率基 站的下行链路接收功率进行范围扩展。 如果使用 RSRP表征下行链路 接收功率， 则可以分别针对每个候选小区 i计算经范围扩展后的
Figure imgf000013_0001
( x )„ 如果使用 RSRP表征下行链路接收功率， 则 可以分别针对每个候选小区 i , 计算经范围扩展后的
RSRQ' RS Qi+Δ; ( χ )0 对于候选小区是宏小区的情况不需要进行扩 展， 但是也可以类似地进行偏移量为 0的范围扩展。 从而在选择模块 312中可以统一对待宏小区和微小区。
选择模块 312通常从候选小区中选择具有最大的经范围扩展的下 行链路接收功率 （例如， 最大的 RSRPi，或最大的 RSRQ'i ) 的那个小 区以便作为其服务小区。 如果将宏小区看作经过了偏移量为 0的范围 扩展， 选择模块 312可以基于经范围扩展的下行链路接收功率按从大 到小的顺序对所有候选小区统一进行排序， 选择排序第一的小区。 或 者选择模块 312可以区分宏小区和微小区 , 首先分别对候选的微小区 和宏小区进行排序， 然后将排序第一的微小区和排序第一的宏小区的 下行链路接收功率进行比较， 以选择二者中的较大者对应的小区。 应 该理解， 在本发明中可以使用已知的任何排序机制， 在此不再赘述。
优选地， 装置 300还包括接收模块 304。 接收模块 304可以配置 用于接收基站的指示和 /或信息。 装置 300可以定期地执行小区选择， 或者响应于基站的指示来执行小区选择。在后一情况下，接收装置 304 需要从基站接收执行小区选择的指示。
优选地， 接收模块 304还可以配置用于接收基站向用户设备发送 的其他信息， 例如调整用于范围扩展的可变的偏移量的各种参数。 基 站可以通过广播信道发送这些信息， 也可以响应于用户设备的请求通 过用户设备专用的信道进行发送。
优选地， 装置 300还包括其他测量模块， 例如测量调整用于范围 扩展的可变的偏移量的所需的各种参数。 例如， 装置 300可以包括速 度测量模块 306 , 用于测量用户设备的移动速度。
优选地， 装置 300还包括自适应调整模块 308 , 其根据功率测量 模块 302和 /或其他测量模块的测量结杲、 以及 /或者接收模块接收的 各种参数， 自适应地调整用于范围扩展的偏移量。 如参考图 2已经详 细说明的， 根据本发明， 可变的偏移量可以根据例如接收功率水平之 间的差异， 基站的业务负载状况以及用户设备的移动速度等等各种因 素进行动态调整。 在此不再详述。
应该理解， 装置 300示出的模块仅是示意性的， 其还可以包括更 多的模块。 例如， 装置 300中还可以包括发送模块， 用于发送用户请 求； 和 /或计算模块， 等等。 另一方面， 装置 300还可以省略一个或多 个示出的模块。 例如， 在不需要考虑用户设备的速度时， 可以省略模 块 306。 本发明的执行小区选择的装置 300可以位于用户设备内， 作为用 户设备的一部分。 装置 300也可以位于与用户设备可通信的连接的其 他设备中。
本发明的执行小区选择的机制通过设计自适应调整的偏移量， 不 仅考虑了接收功率水平， 还考虑了基站之间的负载均衡、 小区切换频 率等等。 可以确保用户设备与最佳的小区相关联。 在使得更多的用户 设备连接到低功率基站的同时， 确保服务的 QoS , 而且提高网络的整 体吞吐量。
以上结合 LTE的异构环境对本发明进行了说明。应当理解本发明 还可以应用于其他支持异构的环境， 例如 WiMax等等。 以上所描述 的实施例是示例性的， 而不是限制性的。 所例举的各个步骤不是必不 可少的， 其顺序也不是限制性的。 例如， 根据实际的需要， 可以定制 小区执行的方法， 增加或删除某些步 。 或者可以以不同的顺序来执 行上述步骤， 或者可以并行地执行某些步骤。 同样， 所例举的用于执 行小区选择的装置和用户设备还可以包括更多或更少的单元。
应当注意， 为了使本发明更容易理解， 上面的描述省略了对于本 领域的技术人员来说是公知的、 并且对于本发明的实现可能是必需的 更具体的一些技术细节。
提供本发明的说明书的目的是为了示例说明和描述， 而不是用来 穷举或将本发明限制为所公开的形式。 对本领域技术人员而言， 许多 修改和变更都是显而易见的。 本领域技术人员还应该理解， 可以通过 软件、 硬件、 固件或者它们的结合的方式， 来实现本发明实施例中的 方法和装置。 硬件部分可以利用专用逻辑来实现； 软件部分可以存储 在存储器中， 由适当的指令执行系统， 例如微处理器、 计算机或大型 机来执行。
因此， 应该理解， 选择并描述实施例是为了更好地解释本发明的 原理及其实际应用， 并使本领域普通技术人员明白， 在不脱离本发明 实质的前提下， 所有修改和变更均落入由权利要求所限定的本发明的 保护范围之内。 在权利要求中， 措词 "包括" 不排除其他的元素和步 骤， 并且措辞 "一个" 不排除复数。 在发明的实际应用中， 一个零件 可能执行权利要求中所引用的多个技术特征的功能。权利要求中的任 何附图标记不应理解为对范围的限制。

Claims

权 利 要 求 书
1. 一种在异构网络中执行小区选择的方法， 所述异构网络包括 宏基站和至少一个低功率基站， 每个基站对应各自的小区， 所述方 法包括：
测量宏基站和低功率基站的下行链路接收功率，
使用可变的偏移量来对低功率基站的下行链路接收功率进行范 围扩展，
基于宏基站的下行链路接收功率和经范围扩展的低功率基站的 下行链路接收功率来选择用户设备要关联的基站。
2. 根据权利要求 1所述的方法， 所述可变的偏移量是根据以下 因素中的至少一个来自适应调整的：
宏基站和低功率基站的下行链路接收功率之差；
宏基站的业务负载；
低功率基站的业务负载； 以及
所述用户设备的移动速度。
3. 根据权利要求 2所述的方法， 其中所述自适应调整包括： 所 述宏基站和低功率基站的下行链路接收功率之差越小， 所述偏移量 被设置为越大。
4. 根据权利要求 2或 3所述的方法，其中所述自适应调整包括： 所述宏基站的业务负载越大和 /或所述低功率基站的业务负载越小， 所述偏移量被设置为越大。
5. 根据权利要求 2或 3所述的方法，其中所述自适应调整包括： 所述用户设备的移动速度越快， 所述偏移量被设置为越小。
6. 根据权利要求 1所述的方法， 其中所述方法是定期执行的。
7. 根据权利要求 1所述的方法， 其中所述方法是根据服务基站 的指示进行的。
8. —种在异构网络中执行小区选择的装置， 所述异构网络包括 宏基站和至少一个低功率基站， 每个基站对应各自的小区， 所述装 置包括： 测量模块， 用于测量宏基站和 /或低功率基站的下行链路接收功 率，
范围扩展模块， 用于使用可变的偏移量来对低功率基站的下行 链路接收功率进行范围扩展，
选择模块， 用于基于宏基站的下行链路接收功率和经范围扩展 的低功率基站的下行链路接收功率来选择所述用户设备要关联的基 站。
9. 根据权利要求 8所述的装置， 进一步包括自适应调整模块， 用于根据以下因素中的至少一个来自适应调整所述可变的偏移量： 宏基站和低功率基站的下行链路接收功率之差；
宏基站的业务负载；
低功率基站的业务负载； 以及
所述用户设备的移动速度。
10. 根据权利要求 9 所述的装置， 其中所述自适应调整模块被 配置成： 所述宏基站和低功率基站的下行链路接收功率之差越小， 所述偏移量被设置为越大。
1 1. 根据权利要求 9或 10所述的装置， 其中所述自适应调整模 块被进一步配置成： 所述宏基站的业务负载越大和 /或所述低功率基 站的业务负载越小， 所述偏移量被设置为越大。
12. 根据权利要求 9或 10所述的装置， 其中所述自适应调整模 块被进一步配置成： 所述用户设备的移动速度越快， 所述偏移量被 设置为越小。
13. 根据权利要求 8 所述的装置， 其中所述装置定期地执行基 站选择。
14， 根据权利要求 8 所述的装置， 其中所述装置响应于服务基 站的指示来执行基站选择。
15. —种用户设备， 其包括根据权利要求 8-14中的任意一项所 述的装置。
PCT/CN2010/071563 2010-04-06 2010-04-06 执行小区选择的方法和装置 WO2011124013A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201080064959.1A CN102823300B (zh) 2010-04-06 2010-04-06 执行小区选择的方法和装置
PCT/CN2010/071563 WO2011124013A1 (zh) 2010-04-06 2010-04-06 执行小区选择的方法和装置

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2010/071563 WO2011124013A1 (zh) 2010-04-06 2010-04-06 执行小区选择的方法和装置

Publications (1)

Publication Number Publication Date
WO2011124013A1 true WO2011124013A1 (zh) 2011-10-13

Family

ID=44762006

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2010/071563 WO2011124013A1 (zh) 2010-04-06 2010-04-06 执行小区选择的方法和装置

Country Status (2)

Country Link
CN (1) CN102823300B (zh)
WO (1) WO2011124013A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013135269A1 (en) * 2012-03-12 2013-09-19 Nokia Siemens Networks Oy Pico cell-selection / handover for tdm eicic heterogenous networks
WO2014023016A1 (zh) * 2012-08-10 2014-02-13 华为技术有限公司 移动性控制的方法和装置

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104105123A (zh) * 2013-04-02 2014-10-15 中兴通讯股份有限公司 一种宏基站与低功率基站协同通信的方法及系统
CN106576259B (zh) * 2014-08-15 2020-05-08 瑞典爱立信有限公司 用于小区选择的方法、rrm节点和计算机可读介质
CN113115363A (zh) * 2021-04-20 2021-07-13 国家计算机网络与信息安全管理中心 异构网络中的移动通信方法、装置与电子设备

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06237208A (ja) * 1993-02-10 1994-08-23 Kokusai Denshin Denwa Co Ltd <Kdd> マイクロセル移動通信方式
US20040029588A1 (en) * 2002-07-15 2004-02-12 Nec Corporation Method for changing over to different frequency at cellular phone system and cellular phone system using the method and base station controlling apparatus in the system and mobile communication terminal in the system
CN101562835A (zh) * 2008-04-17 2009-10-21 中兴通讯股份有限公司 一种终端在分层异构分布式基站间的切换方法
WO2010032351A1 (ja) * 2008-09-19 2010-03-25 パナソニック株式会社 移動端末、マクロ基地局およびセル選択システム

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1277421C (zh) * 2003-01-14 2006-09-27 华为技术有限公司 一种多频段小区选择的实现方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06237208A (ja) * 1993-02-10 1994-08-23 Kokusai Denshin Denwa Co Ltd <Kdd> マイクロセル移動通信方式
US20040029588A1 (en) * 2002-07-15 2004-02-12 Nec Corporation Method for changing over to different frequency at cellular phone system and cellular phone system using the method and base station controlling apparatus in the system and mobile communication terminal in the system
CN101562835A (zh) * 2008-04-17 2009-10-21 中兴通讯股份有限公司 一种终端在分层异构分布式基站间的切换方法
WO2010032351A1 (ja) * 2008-09-19 2010-03-25 パナソニック株式会社 移動端末、マクロ基地局およびセル選択システム

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013135269A1 (en) * 2012-03-12 2013-09-19 Nokia Siemens Networks Oy Pico cell-selection / handover for tdm eicic heterogenous networks
US9271215B2 (en) 2012-03-12 2016-02-23 Nokia Solutions And Networks Oy Pico cell-selection/handover for TDM eICIC heterogenous networks
WO2014023016A1 (zh) * 2012-08-10 2014-02-13 华为技术有限公司 移动性控制的方法和装置
CN103733686A (zh) * 2012-08-10 2014-04-16 华为技术有限公司 移动性控制的方法和装置
US9439124B2 (en) 2012-08-10 2016-09-06 Huawei Technologies Co., Ltd. Mobility control method and apparatus
CN103733686B (zh) * 2012-08-10 2017-07-21 华为技术有限公司 移动性控制的方法和装置

Also Published As

Publication number Publication date
CN102823300B (zh) 2016-01-20
CN102823300A (zh) 2012-12-12

Similar Documents

Publication Publication Date Title
US9084165B2 (en) Systems and methods for deployment operations for small cells in self-organizing networks
EP2430857B1 (en) Technique for instructing mobile stations communicating with cooperating access nodes
US10390261B2 (en) Load balancing schemes for idle mode user equipment
US10159111B2 (en) Radio resource management in a telecommunication system
JP6361060B2 (ja) 複数の異種無線ネットワークに対するユーザモビリティ制御
CN102474784B (zh) Rat间重选/切换参数优化
KR101637587B1 (ko) 펨토 기지국에서 연결 설정을 제어하는 방법 및 단말에서 연결을 설정하는 방법
KR101899770B1 (ko) 통신 시스템 및 로드 밸런싱 방법
JP5498860B2 (ja) 無線基地局、無線通信システム、及び制御方法
WO2011149081A1 (ja) 無線通信システム、無線基地局、及び通信制御方法
GB2559424A (en) Communication system
US20180020388A1 (en) Method of automatically adjusting mobility parameter
EP2648458A1 (en) Mobile communications network and wireless base station
WO2012062143A1 (zh) 一种小区间驻留负荷均衡的方法及装置
WO2013132289A1 (en) Re-selection optimization for packet and circuit switched connections
WO2011124013A1 (zh) 执行小区选择的方法和装置
Zhang et al. A two-layer mobility load balancing in LTE self-organization networks
US9462542B2 (en) Method and base station for a cell selection
US10154417B2 (en) Network node and a method therein for computing cell range expansion (CRE) values
US20140348014A1 (en) Radio base station and method of controlling transition between radio systems
KR20180132913A (ko) 개선된 셀 재선택 절차를 위한 무선 장치 및 방법
KR20110120615A (ko) 셀룰러 시스템에서 인접 셀 간 셀 재 선택을 수행하는 방법
KR20180089945A (ko) 셀간 부하 균등 제어 방법 및 장치
KR101543145B1 (ko) 트래픽 부하 제어장치 및 방법, 그의 단말장치
KR20120126453A (ko) 근거리통신망으로의 트래픽 분산 방법 그리고 이를 구현한 제어국

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 201080064959.1

Country of ref document: CN

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10849250

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 10849250

Country of ref document: EP

Kind code of ref document: A1