The present application claims priority from Japanese patent application JP 2009-159411 filed on Jul. 6, 2009, the content of which is hereby incorporated by reference into this application.
The present invention relates to a wireless communication system in which data transmission and reception take place between a wireless base station apparatus and a wireless mobile station. The invention also relates to a wireless communication base station and a wireless mobile station in such a wireless communication system. Particularly, the invention relates to a technique in which a wireless base station apparatus manages allocation of wireless resources to wireless mobile stations.
Generally, in a digital mobile communication system utilizing OFDMA (Orthogonal Frequency Division Multiple Access), communication with mobile stations is performed using resources partitioned into units of frequency and time. As discussed in Wang Anchun, Xiao Liang, Zhou Shidong Xu Xiiin, Yao Yan, “Dynamic resource management in the fourth generation wireless systems,” Proc. ICCT 2003, a base station performs scheduling in which it measures a reception quality from the interference and received power for each resource, decides which resource to be used for communication with each mobile station from the measured reception quality, decides a transmission rate, notifies a mobile station about the resource, and initiates communication with the mobile station. In a fourth generation wireless communication system like IMT-Advanced, it becomes possible that respective base stations perform communication using a same frequency and different base stations utilize a common resource in order to improve frequency usage efficiency, as suggested in 3GPP, TR36.814 v0.4.1, February 2009 and IEEE802.16m, System Description Document, IEEE802.16m-08/003r8, April 2009. Here, the reception quality of each resource depends on interferences from other cells.
Besides conventional best effort services, lately, there are increasing demands for services for which it is important to guarantee QoS (Quality of Service) in terms of a transmission rate and delay time, for example, VoIP (Voice over Internet Protocol) and motion picture transmission. For example, in motion picture transmission, because the transmission rate changes depending on picture quality, it is required to guarantee a minimum sustained rate to maintain picture quality and further to achieve a high transmission rate in accordance with a motion picture rate. Therefore, in QoS guaranteed resource allocation as disclosed in JP-A-2008-211759 and JP-A-2006-157323, resources are preferentially allocated for a service with a high QoS guarantee priority to achieve guaranteeing a minimum sustained rate and, then, resource allocation is performed for a service with a low priority
In this context, in resource allocation according to conventional scheduling, one base station cannot know resource allocation performed by other base stations. Consequently, when another base station changes resource allocation, its interference changes, which in turn varies a given transmission rate, thus making it difficult to guarantee a minimum sustained rate. Interference change due to downlink resource allocation changes in adjacent base stations is depicted in
One aspect of the present invention to solve at least one of the problems noted above resides in a wireless communication system comprising a plurality of wireless base station apparatuses and a plurality of mobile station apparatuses, wherein the wireless base station apparatuses and the mobile station apparatuses are capable of communication with each other via radio resources. Each wireless base station apparatus is configured to allocate first resources for transmission/reception of data with a specified capacity among data to be transmitted/received for a given period and notify results of allocation to the mobile station apparatuses. Further, in another aspect, when a wireless base station apparatus allocates resources to mobile station apparatuses, the base station is configured to allocate second resources to the mobile station apparatuses for a duration shorter than the given duration for transmission/reception of data other than the data with a specified capacity among the data to be transmitted/received.
According to one aspect of the present invention, each wireless base station apparatus allocates first resources for a given period, thereby resulting in reducing fluctuation in interferences. It is thus possible to stabilize a transmission rate and guarantee a minimum sustained rate.
In the following, with reference to the drawings, detailed descriptions are provided for a wireless communication system to which the invention is applied and a wireless communication base station and a wireless mobile station in the wireless communication system.
A wireless communication system pertaining to the present embodiment is applied in network architecture, for example, as is shown in
Planar arrangements of base stations are shown in
An example of resources which are used for wireless communication in the present embodiment is shown in
The number of downlink resources is denoted by Pd and the number of uplink resources is denoted by Pu, and each resource is numbered 1, 2, . . . , Pd, and 1, 2, . . . , and Pu. Abase station decides a resource to be used for communication with a mobile station from among the resources shown in
The base station includes a controller 710, an antenna 709 which transmits and receives radio waves to/from a mobile station, a switch 708 connected to the antenna 709 to switch between transmission and reception, a NW interface 701 which is connected to a connection link with a router 401, an upper layer controlling unit 702 connected to the NW interface 701, a transmission RF (Radio Frequency) unit 706 and a reception RF unit 707 connected to the switch 708, a base band processing unit 704 for base station connected to the transmission RF unit 706, an base band processing unit 705 for mobile station connected between the upper layer controlling unit 702 and the reception RF unit 707, and a scheduling unit 703 connected between the upper layer controlling unit 702 and the base band processing unit 704 for base station.
A hardware structure of a base station is described, using a block structural diagram as shown in
As for downlink, data transferred from the NW interface 701 is first processed by the upper layer controlling unit 702. Then, the scheduling unit 703 measures interference on each resource and decides downlink and uplink resource allocations, using service information from the upper layer controlling unit 702, a signal from the reception RF unit 707, and a signal from the base band processing unit 705 for mobile station. However, information that is used by the scheduling unit 703 is not limited to those mentioned above. It is conceivable to use information from other processing units. Following that, data is transferred to the base band processing unit 704 for base station and undergoes RF processing in the transmission RF unit 706. Then, the switch 708 switches to transmission and a radio signal is transmitted from the antenna 709. The above process operates according to control signals from the controller 710. The controller 710 is a program module which is executed by the processor 3701.
As for uplink, the switch 708 first switches to reception and a radio signal is received by the antenna 709. Then, the received data undergoes RF processing in the reception RF unit 707. Following that, the data is transferred to the base band processing unit 705 for mobile station, processed by the upper layer controlling unit 702, and transmitted from the NW interface 701. The above process operates according to control signals from the controller 710.
A hardware structure of a mobile station is described, using a block structural diagram as shown in
As for uplink, data transferred from the user interface 3905 is first processed by the upper layer controlling unit 802. Then, the data is transferred to the uplink base band processing unit 804 and undergoes RF processing in the transmission RF unit 806. The switch 808 switches to transmission and a radio signal is transmitted from the antenna 809. The above process operates according to control signals from the controller 810.
As for downlink, the switch 808 first switches to reception and a radio signal is received by the antenna 809. Then, the received signal undergoes RF processing in the reception RF unit 807. Following that, the data is transferred to the downlink base band processing unit 705, processed by the upper layer controlling unit 702, and output to the user interface 801. An interference measurement unit 813 measures interference on a resource and transfers the measured interference to the upper layer controlling unit 802. The above process operates according to control signals from the controller 810. Here, the user interface is not limited to this and an interface with another device is conceivable.
A sequence diagram of scheduling that is performed by the scheduling unit 703 is shown in
First, at step 901, each mobile station measures interference values on resources to measure reception quality. Here, as an interference metric value, CINR (Carrier to Interference plus noise ratio), interference power, etc. may be used. Hereinafter, CINR is assumed as an example of an interference metric value. Measured CINR values are averaged in frequency and time domains. Units of averaging them in the frequency domain are a whole bandwidth and sub-bandwidths into which the whole bandwidth is divided. If measured CINR values are averaged over the whole bandwidth, the amount of information when CINR is reported is reduced, but precision deteriorates. On the other hand, if measured CINR values are averaged over each of the sub-bandwidths, the amount of information when CINR is reported is increased, but precision is better. As for averaging measured CINR values in the time domain, an averaging method per time window as expressed by Equation 1 and an averaging method using a forgetting factor as expressed by Equation 2 are possible. In the following Equations 1 and 2, γave (t) is averaged CINR over a frame numbered T is a time window (in frame units) over which averaging is done, γ (i) is frequency-averaged CINR over a frame numbered i, and λ is a forgetting factor (0<λ≦1). When the forgetting factor λ is set smaller, measured CINR values are averaged with earlier CINR values being more weighted. When the forgetting factor λ is set larger, measured CINR values are averaged with later CINR values being more weighted. However, methods of averaging interference values are not limited to those mentioned above. Any method enabling averaging interference values in both frequency and time domains may be used nonlimitingly.
Next, at step 902, the mobile station reports interference values measured at step 901 to the base station. Reporting interference values on downlink is performed such that each mobile station reports to the base station CINR 1001 on each of resources having respective unique resource indices 1002, using a table as shown in
At step 903, the base station accumulates interference values reported from each mobile station and creates a table holding CINR values for each resource for each mobile station.
At step 904, the base station decides resource allocations to each mobile station using CINRs reported from mobile stations and accumulated in the table at step 903. At step 905, the base station notifies allocated resources to each mobile station by the transmitter and receiver 3703. The mobile station receives by the antenna 809 information for a result of resource allocation from the base station and will transmit and receive data to/from the base station using the allocated resources. The mobile station will be transmitting and receiving data with the operations of software shown in
The scheduling unit 703 of a base station relevant to the present embodiment described with regard to
The interference table 106 is shown in
The interference fluctuation table 107 is shown in
The allocating duration table 102 is shown in
The interference measurement unit 104 and the interference fluctuation measurement unit 105 operate by receiving a measurement signal from the controller 710, instructing to update the interference table 106 and the interference fluctuation table 107. The guaranteed resource classification unit 101 receives from the controller 710 a signal to update the rest of allocating duration 1304 (
The present embodiment is characterized as follows. According to interference measurement results reported from mobile stations, resources having a small fluctuation in interference are classified as guaranteed resources. Guaranteed resources are allocated up to satisfying a minimum sustained rate so as to continue their allocations for a longer duration. At the same time, non-guaranteed resources are allocated for a shorter duration for a service that should be provided at a rate more than the minimum sustained rate.
The interference measurement unit 104 looks for which mobile station is reporting CINRs, calculates and outputs a time average of CINRs for each resource reported from the mobile station as an interference measurement result, and updates the interference table 106. A flowchart hereof is shown in
At step 1401, the unit initializes the MS index to look for to n=1 in order to look for a mobile station reporting CINRs.
At step 1402, if a MS index n is reporting CINRs, the unit goes to step 1403.
At step 1403, the unit initializes the resource index to p=1 in order to update the interference value for each resource.
At step 1404, the unit extracts CINR αp corresponding to an interference value on a resource index p from the reported CINR list shown in
At step 1405, the unit extracts CINR γdpn corresponding to an interference value associated with the MS index n and the resource index p from the interference table 106 shown in
At step 1406, the unit calculates a time average CINR using the CINRs extracted at steps 1404 and 1405, e.g., according to Equation 3, and goes to step 1407. In the following equation, λ is a forgetting factor.
γdpn=(1−λ)γdpn+λαp [Equation 3]
At step 1407, the unit updates the above value of ydpn in the interference table 106 shown in
At step 1408, the unit increments the resource index to update.
At step 1409, if p>Pd, the unit decides that updating all resources is complete and goes to step 1410. If p≦Pd, the unit decides that updating all resources is not complete and returns to step 1404.
At step 1410, the unit increments the MS index to look for.
At step 1411, if n>N, the unit decides that looking for all mobile stations is complete and terminates the processing. If n≦N, the unit decides that looking for all mobile stations is not complete and returns to step 1402.
If the MS index n is not reporting CINRs at step 1402, the unit goes to step 1410 without updating the CINR on the resource.
Time averaging of CINRs at step 1406 may be done in accordance with any other formula not limited to Equation 3. It is also possible to output reported CINRs simply as interference measurement results without averaging the CINRs. In that case, steps 1405 and 1406 are not operative.
The interference fluctuation measurement unit 105 looks for which mobile station is reporting CINRs, calculates a CINR fluctuation value from CINRs for each resource reported from the mobile station, and updates the interference fluctuation table 107. A flowchart hereof is shown in
At step 1501, the unit initializes the MS index to look for to n=1 in order to look for a mobile station reporting CINRs.
At step 1502, if a MS index n is reporting CINRs, the unit goes to step 1503.
At step 1503, the unit initializes the resource index to p=1 in order to update the interference fluctuation value for each resource.
At step 1504, the unit extracts CINR αp corresponding to an interference value on a resource index p from the reported CINR list shown in
At step 1505, the unit extracts an interference fluctuation value βdpn and an long interference mean δdpn associated with the MS index n and the resource index p from the interference fluctuation table shown in
At step 1506, the unit calculates a time average CINR using the CINR αp extracted at step 1504 and the long interference mean δdpn, e.g., according to Equation 4, updates the long interference mean δdpn, and goes to step 1512. In the following equation, λ1 is a forgetting factor, the previous long interference mean is denoted by δdpn (t−1), and the updated long interference mean is denoted by δdpn (t). Preferably, the previous long interference mean is more weighted, because δdpn is used to calculate an interference fluctuation value βdpn. That is, λ1 should be set to a value approximate to 0, e.g., λ1=0.01.
δdpn(t)=(1−λ1)δdpn(t−1)+λ1αp [Equation 4]
At step 1512, the unit updates the interference fluctuation value βdpn using the CINR αp extracted at step 1504, the interference fluctuation value βdpn extracted at step 1505, and the long interference mean δdpn(t) updated at step 1506, e.g., according to Equation 5. In the following equation, λ2 is a forgetting factor, the previous interference fluctuation value is denoted by βdpn(t−1), and the updated interference fluctuation value is denoted by βdpn(t).
βdpn(t)=(1−λ2)βdpn(t−1)+λ2(αp−δdpn(t))2 [Equation 5]
At step 1507, the unit updates the above values of βdpn and δdpn in the interference table 106 and goes to step 1508.
At step 1508, the unit increments the resource index to update.
At step 1509, if p>Pd, the unit decides that updating all resources is complete and goes to step 1510. If p≦Pd, the unit decides that updating all resources is not complete and returns to step 1504.
At step 1510, the unit increments the MS index to look for.
At step 1511, if n>N, the unit decides that looking for all mobile stations is complete and terminates the processing. If n≦N, the unit decides that looking for all mobile stations is not complete and returns to step 1502.
If the MS index n is not reporting CINRs at step 1502, the unit goes to step 1510 without updating the CINR on the resource.
Time averaging of CINRs at step 1506 may be done in accordance with any other formula not limited to Equation 4.
Measuring interference fluctuation at step 1512 may be done in accordance with any other formula not limited to Equation 5.
Next, operations of the guaranteed resource classification unit 101 are described below. The guaranteed resource classification unit 101 refers to the interference fluctuation table 107 and classifies resources having a small interference fluctuation value from among resources with the rest of allocating duration=0 in the allocating duration table 102 in
At step 1601, the unit initializes the resource index for which the unit should decide whether to classify it as guaranteed resources.
At step 1602, if not p>Pd, i.e., it is determined that classifying all resources is not complete, the unit goes to step 1611.
At step 1611, if the rest of allocating duration is 0 for a resource index p in the allocating duration table 102, the unit goes to step 1603.
At step 1603, the unit initializes the MS index for which its interference fluctuation value should be checked and initializes sum=0 to calculate an average interference fluctuation value.
At step 1604, the unit extracts an interference fluctuation value βdpn associated with a MS index n and a resource index p from the interference fluctuation table 107 shown in
At step 1605, the unit calculates sum+=βdpn.
At step 1606, the unit increments the MS index.
At step 1607, if not n>N, i.e., it is determined that checking the interference fluctuation values evaluated for all mobile stations is not complete, the unit returns to step 1604. If n>N, i.e., it is determined that checking the interference fluctuation values evaluated for all mobile stations is complete, the unit goes to step 1608.
At step 1608, if it is determined that an average sum/N of the interference fluctuation values is less than a threshold value ε, the unit judges the resource as guaranteed type and goes to step 1609. If the average sum/N of the interference fluctuation values is not less than threshold value ε, the unit judges the resource as non-guaranteed type and goes to step 1610. Here, the threshold value ε may be initially set or may be configured from a network entity, e.g., GW 402 as shown in
At step 1609, the unit updates the rest of allocating duration 1304 for the resource to L in the allocating duration table 102, sorts the resource as guaranteed type, and goes to step 1610. Here, the rest of allocating duration L may be initially set or may be configured from a network entity, e.g., GW 402 as shown in
At step 1611, if the rest of allocating duration 1304 is not 0 for a resource index p in the allocating duration table 102, the unit goes to step 1610.
At step 1610, the unit increments the resource index and returns to step 1602.
At step 1602, if p>Pd, i.e., classifying all resources is complete, the unit terminates the processing.
The flowchart of
Although an average is used as an interference fluctuation value for comparison to the threshold value, there is no limitation to this and an alternative is possible, provide that it represents a degree of fluctuation in interference on resources. For example, a value representing a maximum interference fluctuation value for the resource among the respective users may be compared to the threshold value. To illustrate operations of the guaranteed resource classification unit 101 in this case, the flowchart is shown in
Unlike
To classify guaranteed resources, it is also possible to use average interference values for a long period besides interference fluctuation values. In this case, with regard to resources judged as guaranteed type, for a resource whose interference value for a long period is less than the threshold value ε, that is, whose average CINR for a long period is less than the threshold value c, experiencing a large interference continuously, the unit does not sort it as guaranteed type. Thereby, it is possible to prevent allocating resources with deteriorated CINR, although conditional branching increases.
The allocated resource decision unit 103 is depicted in a block diagram as shown in
A flowchart of the guaranteed allocation unit 1801 is shown in
At step 1901, the unit initializes the resource index to p=1 and the MS index to n=1 in order to retrieve guaranteed resources in order and initializes a flag indicating that allocation yielding up to a minimum sustained rate is complete to flag=0.
At 1902, the unit extracts a minimum sustained rate to be guaranteed from a QoS parameter for a MS index n.
At 1903, the unit refers to the allocating duration table 102 shown in
At step 4501, the unit extracts the minimum sustained rate 4302 to be guaranteed for the MS index n 4301 from the QoS table in
At step 4502, the unit refers to the allocating duration table 102 illustrated in
At step 4503, if D≦L, that is, it is determined that the data amount to be transmitted at the current allocation timing is larger than the data amount required to satisfy the minimum sustained rate, the unit goes to step 4504. If D>L, that is, it is determined that the data amount to be transmitted at the current allocation timing is smaller than the data amount required to satisfy the minimum sustained rate, the unit goes to step 4505.
At step 4504, the unit decides that allocation yielding up to the minimum sustained rate is complete and terminates the processing.
At step 4505, the unit decides that allocation yielding up to the minimum sustained rate is not complete and terminates the processing.
If it is decided that resource allocation yielding up to the minimum sustained rate to the MS index n is complete at step 1905, the unit goes to step 1912.
At step 1912, the unit increments the flag and the MS index and goes to step 1913.
At step 1913, if flag=N, that is, allocation yielding up to the minimum sustained rate is complete for all mobile stations, the unit terminates the processing. If flag<N, that is, allocation yielding up to the minimum sustained rate is not complete for all mobile stations, the unit goes to step 1914. At step 1914, if it is determined that n≦N, the unit returns to step 1902. If it is determined that n>N, the unit goes to step 1915.
At step 1915. the unit initializes the MS index to n=1 and returns to step 1902.
However, if it is decided that resource allocation yielding up to the minimum sustained rate to the MS index n is not complete at step 1905, the unit goes to step 1906. At step 1906, the unit updates the MS index to which the resource index p is allocated to n in the column 1303 of MS index to which resource is allocated in the allocating duration table 102 illustrated in
At step 1907, the unit increments the MS index, initializes the flag, and goes to step 1908.
At step 1908, if it is determined that n>N, the unit goes to step 1909. If it is determined that n≦N, the unit goes to step 1910.
At step 1909, the unit initializes the MS index to n=1 and goes to step 1910.
At step 1903, the unit refers to the allocating duration table 102 and, if the rest of allocating duration 1304=0 for the resource index p, that is, the resource is not guaranteed type, the unit goes to step 1910.
At step 1910, the unit increments the resource index and goes to step 1911.
At step 1911, if p Pd, that is, retrieving all resources is not complete, the unit returns to step 1902. If p>Pd, that is, retrieving all resources is complete, the unit terminates the processing.
The flowchart of
The flowchart of
The flowchart of
At step 4901, the guaranteed allocation unit initializes the MS index to n=1 and temp=0 in order to count the number of mobile stations for which resources yielding up to the minimum sustained rate are allocated.
At step 4902, the unit checks whether or not resources yielding up to the minimum sustained rate have been allocated to the MS index n, similarly to step 1905. If resources yielding up to the minimum sustained rate have been allocated, the unit goes to step 4903; if not, the unit goes to step 4904.
At step 4903, the unit increments tmp.
At step 4904, the unit increments the MS index.
At step 4905, if n≦N, that is, retrieving all mobile stations is not complete, the unit returns to step 4902. If n>N, that is, retrieving all mobile stations is complete, the unit goes to step 4906.
At step 4906, if not tmp=N, that is, resources yielding up to the minimum sustained rate are not allocated to all mobile stations, the unit goes to step 4907. If tmp=N, that is, resources yielding up to the minimum sustained rate are allocated to all mobile stations, the unit goes to step 4908.
At step 4907, the unit sets ε+=δ to increase the threshold value ε of interference fluctuation and terminates the processing. Here, a value of δ may be initially set or may be configured from a network entity, e.g., GW 402 and held on the data memory 3706 of the base station.
At step 4908, the unit sets ε−=δ to decrease the threshold value ε of interference fluctuation, terminates the processing to update the threshold value 4909, and returns to step 1911.
The guaranteed allocation unit 1801 may allocate a variable number of guaranteed resources to each mobile station according to interference and interference fluctuation values for each mobile station, instead of evenly allocating guaranteed resources to the respective mobile stations as illustrated in
In the additional allocation unit 1802, the inner memory 1803 resides to store cost function values for the pairs of resource indices and MS indices. This unit has a cost function table 2100 as shown in
At step 2001, the unit initializes the resource index to p=1 and all cost function values to −1.
At step 2002, if the MS index to which resource is allocated=0 in the allocating duration table 102 shown in
At step 2003, the unit refers to the interference table 106 shown in
Here, Rn(t)=Rn(t−1)+rpn, where Rn(t) is an average transmission rate until the current allocation timing, Rn(t−1) is an average transmission rate until the previous allocation timing. rpn is a transmission rate in a moment, obtained from CINR by Equation 6.
At step 2004, if p≦Pd, that is, calculating the cost function for all resources is not complete, the unit goes to step 2005.
At step 2002, if not the MS index to which resource is allocated=0 in the allocating duration table 102 shown in
At step 2005, the unit increments the resource index and returns to step 2002.
At step 2004, if p>Pd, that is, calculating the cost function for all resources is complete, the unit goes to step 2006.
At step 2006, the unit extracts a pair of a resource index p and a MS index n, the pair having the largest value of cost function, provide that the resource index p is a resource for which the rest of allocating duration 1304=0, that is, non-guaranteed resource not allocated.
At step 2007, if allocation to the MS index n is not complete, the unit goes to step 2008.
At step 2008, the unit updates the MS index to which the resource index p is allocated to n in the column of MS index to which resource is allocated in the allocating duration table 102 shown in
At step 2009, the unit updates the rest of allocating duration 1304 to 1.
At step 2010, the unit recalculates and updates cost function values of the MS index n to which the resource has been allocated and returns to step 2006. When a resource is allocated to a mobile station, the transmission rate for the mobile station increases. Thus, it is preferable to lower the priority of the mobile station to which the resource has been allocated in the next resource allocation. When calculating cost function values by Equation 6, if previous resource allocation to a mobile station is done, the average transmission rate for the mobile station should be modified, as in Equation 7.
R
n(t)=Rn(t)+γpn [Equation 7]
At step 2007, if allocation to the MS index n is complete, the unit goes to step 2011.
At step 2011, if required allocation to all mobile stations is not complete, the unit goes to step 2012.
At step 2012, the unit initializes all cost function values of the MS index n to −1 and returns to step 2006.
At step 2011, if required allocation to all mobile stations is complete, the unit goes to step 2013.
At step 2013, the unit decrements the rest of allocating duration 1304 by 1 for all allocated resources and terminates the processing.
The flowchart of
For updating cost function values at step 2010, any other algorithm is possible, not limited to Equation 7, provided that it coordinates with the algorithm for calculating cost function values at step 2003.
Although it is assumed to allocate and reallocate resources on a per-frame basis in the present embodiment, it may be assumed to allocate and reallocate resources in units of R (R>1) frames. In this case, R or an integral multiple of R is set in the column of the rest of allocating duration 1304 of the allocating duration table 102 shown in
Resource allocation operation in the whole wireless communication system relevant to the present embodiment is described using
Further, the advantageous effect of the present embodiment is described in perspective of QoS.
A second embodiment as another example of embodiment of the present invention is described below. In the second embodiment, as can be seen in a block structural diagram of the scheduling unit of a base station, as is shown in
An interference measurement unit 2304, a interference fluctuation measurement unit 2305, an interference table 2306, an interference fluctuation table 2307, and a allocating duration table 2302 are the same as in the first embodiment. The structure of a allocated resource decision unit 2303 is the same as in
The guarantee calculation unit 2301 calculates guarantees and stores them into a guarantee table 2308, in which a resource with a higher guarantee is more likely to be classified as guaranteed type. The guarantee table 2308 is shown in
At step 2401, the unit initializes the resource index to p=1 and the MS index to n=1.
At step 2402, the unit extracts an interference value γpn and an interference fluctuation value βpn from the interference table 2306 and the interference fluctuation table 2307.
At step 2403, the unit calculates a guarantee from the interference value γpn and interference fluctuation value βpn according to Equation 8 below.
At step 2404, the unit stores the calculated guarantee into the guarantee table 2308.
At step 2405, the unit increments the resource index.
At step 2406, if p≦Pd, that is, calculating guarantees for all resources is not complete, the unit returns to step 2402. If p>Pd, that is, calculating guarantees for all resources is complete, the unit goes to step 2407.
At step 2407, the unit initializes the resource index to p=1 and increments the MS index.
At step 2408, if n≦N, that is, calculating priority levels for all mobile stations is not complete, the unit returns to step 2402. if n>N, that is, calculating priority levels for all mobile stations is complete, the unit terminates the processing.
For calculating the guarantee at step 2403, any other algorithm, not limited to Equation 8, is possible, provided that it gives a higher guarantee to a resource and a mobile station having a smaller interference fluctuation value. For example, instead of using interference values, average interference values for a long period may be used to set up a classifying policy so that resources having a smaller fluctuation and a higher average value are more likely to be classified as guaranteed type.
The flowchart of
The guaranteed allocation unit 1801 in the allocated resource decision unit 2303 refers to the guarantee table 2308, regards pairs of mobile stations and resources with higher guarantees as guaranteed resources in descending order of guarantee, allocates them, and sets their duration of allocation longer in the allocation duration table. A flowchart of this operation is shown in
At step 2601, the unit refers to the guarantee table 2308 and extracts a resource index p and a MS index n having the highest guarantee.
At step 2602, the unit extracts a minimum sustained rate from a QoS parameter for the extracted MS index n, as in the first embodiment.
At step 2603, if the rest of allocating duration is not 0 for the resource index p in the allocating duration table 2302 shown in
At step 2604, if resource allocation yielding up to the minimum sustained rate have to the MS index n is not complete, the unit goes to step 2605.
At step 2605, the unit updates the MS index to which the resource index p is allocated to n in the column of MS index to which resource is allocated in the allocating duration table 2302 shown in
At step 2606, the units sets guarantee=−1 for all mobile stations associated with the resource index p in the guarantee table 2308, so that the resource index p will not be selected subsequently.
At step 2604, if resource allocation yielding up to the minimum sustained rate have to the MS index n is complete, the unit goes to step 2608.
At step 2608, the units sets guarantee=−1 for all resources associated with the MS index n in the guarantee table 2308, so that the MS index n will not be selected subsequently, and goes to step 2607.
At step 2607, if not all values of guarantee in the guarantee table 2308 are −1, that is, allocation of guaranteed resources is not complete, the unit returns to step 2601. if all values of guarantee in the guarantee table 2308 are −1, that is, allocation of guaranteed resources is complete, the unit terminates the processing.
Setting guarantee=−1 in steps 2606 and 2608 is not restrictive; guarantee may be set to any other value, so that the resource or mobile station will not be selected subsequently. For example, guarantee may be set to a negative largest value.
The flowchart of
Resources not allocated by the guaranteed allocation unit are in turn allocated by the additional allocation unit, as in the first embodiment.
In the second embodiment, in addition to the effect achieved by the first embodiment, it is possible to identify guaranteed resources on a per-mobile station basis and to improve the stability of a transmission rate.
A third embodiment as another example of embodiment of the present invention is described below.
In the third embodiment, as can be seen in a block structural diagram of the scheduling unit of a base station, as is shown in
A flowchart of operations of the initial state updating unit 2709 is shown in
At step 2801, the unit decides a resource index p where the initial state is to be updated.
At step 2802. the unit sets the rest of allocating duration 1304 to L for the resource index p in the allocating duration table.
At step 2803, if there is a resource whose initial state is to be updated, the unit returns to step 2801. If there is no resource whose initial state is to be updated, the unit terminates the processing.
In step 2801, a resource index p may be determined in any manner; for example, it may be determined randomly.
In step 2803, a criterion for deciding whether there is a resource whose initial state is to be updated may be set in an arbitrary manner. For example, a number of resources to be taken as guaranteed type may be set and the process may be repeated until the set number of resources is reached.
The flowchart of
In addition to the effect achieved by the first embodiment, the third embodiment provides an advantageous effect, i.e., it is possible to reduce time before plural base stations share guaranteed resources by initially setting up guaranteed resources in the allocating duration table.
A fourth embodiment as another example of embodiment of the present invention is described below. In the fourth embodiment, a dummy data insertion unit 2910 is added to the base station (scheduling unit), as is shown in
A flowchart of operations of the dummy data insertion unit 2910 is shown in
At step 3001, from the allocating duration table, the unit, counts the number X of resources for which the rest of allocating duration>0, i.e., indicating guaranteed resources and allocated MS index=0, i.e., no allocation of the resource to a mobile station is done.
At step 3002, the unit compares X to a threshold Xlim with regard to the number of guaranteed resources not allocated. If X>Xlim, the unit goes to step 3003. If X≦Xlim, the unit terminates the processing.
At step 3003, the unit randomly chooses a number Xlim of resources from the X guaranteed resources not allocated.
At step 3004, the unit inserts dummy data in the resources selected at step 3003 and terminates the processing. Here, dummy data may be arbitrary and is discarded when received.
Randomly selecting a number Xlim of resources in step 3003 is not restrictive; it is only required to choose a number Xlim of resources. Further, the flowchart of operations of the dummy data insertion 2910 is not limited to the foregoing and its variants are possible, provided that the process includes selecting a thresholded number of guaranteed resources not allocated and inserting dummy data therein.
In addition to the effect achieved by the first embodiment, the fourth embodiment makes it possible to prevent increase of fluctuation in interferences arising from guaranteed resources not allocated to mobile stations, even in a situation where, from a plurality of mobile stations, packets of a sufficient data amount to yield a minimum sustained rate do not arrive at a base station due to network congestion, service disruption, etc. In other words, the fourth embodiment makes it possible to share guaranteed resources among base stations, as described using
A fifth embodiment as another example of embodiment of the present invention is described below.
It is assumed that mobile stations report interference values in the first to fourth embodiments. In contrast, in the fifth embodiment, a mobile station is provided with the interference measurement unit 104 and the interference fluctuation measurement unit 105 residing in a base station and reports results calculated by the above units to a base station. A block structural diagram of a mobile station including software-implemented components is shown in
A sequence of scheduling in the fifth embodiment is shown in
At 3403, the base station accumulates reported interference and interference fluctuation values in the interference table and the interference fluctuation table as described in the first embodiment. Subsequent sequence is the same as for resource allocation in the first embodiment.
According to the fifth embodiment, in addition to the effect achieved by the first embodiment, mobile stations perform the above-described report and this can contribute to decreasing the number of circuits needed for classifying guaranteed resources in a base station and manufacturing a base station at less cost. Also, this can contribute to power saving of a base station in resource allocation.
A sixth embodiment as another example of embodiment of the present invention is described below.
In the sixth embodiment, a mobile station described in the fifth embodiment is further provided with a guaranteed resource classification unit 101 and reports resource indices judged as guaranteed resources to a base station. A block structural diagram of a mobile station including software-implemented components is shown in
At 3503, the base station accumulates reported interference values and results of guaranteed resource decision in the interference table and the allocating duration table. Subsequent operations of resource allocation performed by the base station, based on whether each resource is guaranteed are the same as in the first embodiment. However, results of decision as to whether a resource is guaranteed reported from mobile stations are not limited to the foregoing. Any information indicating whether each resource is guaranteed is possible.
According to the sixth embodiment, in addition to the effect achieved by the first embodiment, mobile stations perform the above-described report and this can contribute to decreasing the number of circuits needed for classifying guaranteed resources in a base station and manufacturing a base station at less cost. Also, this can contribute to power saving of a base station in resource allocation.
A seventh embodiment as another example of embodiment of the present invention is described below.
In the seventh embodiment, a mobile station described in the fifth embodiment is further provided with a guarantee calculation unit 2301 and reports guarantee to a base station. A block structural diagram of a mobile station including software-implemented components is shown in
At 3604, the base station accumulates reported interference values and guarantee values in the interference table and the guarantee table. Subsequent operations of resource allocation are the same as in the second embodiment.
According to the seventh embodiment, in addition to the effect achieved by the first embodiment, mobile stations perform the above-described report and this can contribute to decreasing the number of circuits needed for classifying guaranteed resources in a base station and manufacturing a base station at less cost. Also, this can contribute to power saving of a base station in resource allocation.
With regard to the fifth to seventh embodiments, while a mobile station holds measurement results per resource in the tables shown in
Other aspects of the present invention are set forth below.
A wireless base station apparatus, one of a plurality of wireless base station apparatuses capable of communication with a plurality of mobile station apparatuses via radio resources, the base station apparatus including a resource classification unit that classifies the radio resources into guaranteed resources to be allocated to one of the mobile station apparatuses and set to continue to be allocated during a preconfigured duration and second resources to be allocated to one of the mobile station apparatuses and set to continue to be allocated during a duration shorter than the preconfigured duration; a resource allocation unit that allocates the guaranteed resources for transmission/reception of data with a specified capacity and allocates the second resources for transmission/reception of data other than the data with a specified capacity; and a resource allocation notification unit that notifies the mobile station apparatuses of the results of allocation performed by the resource allocation unit.
A mobile station apparatus communicating with a wireless base station apparatus via radio resources, the mobile station apparatus including an interference fluctuation measurement unit that deriving from interferences of the radio resources a set of fluctuation values of the interferences; a radio resource classification unit that classifies the radio resources into guaranteed resources to be allocated by the wireless base station apparatus to the mobile station apparatus during a preconfigured duration and second resources to be allocated by the wireless base station apparatus to the mobile station apparatus during a duration shorter than the preconfigured duration, based on the set of fluctuation values; and a resource classification notification unit that notifies the wireless base station apparatus of the results of the classifying performed by the resource classification unit.
Number | Date | Country | Kind |
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2009-159411 | Jul 2009 | JP | national |