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Scheduling method and control station apparatus

a control station and scheduling method technology, applied in the direction of multiplex communication, frequency-division multiplex, wireless commuication services, etc., can solve the problems of inability to reserve as many consecutive unallocated subcarriers, and terminals cannot have subcarriers allocated thereto

Inactive Publication Date: 2014-07-22
SHARP KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0022]The present invention has been made in view of such a problem, and it is therefore an object of the present invention to provide a scheduling method and a control station apparatus that can properly allocate consecutive subcarriers to terminals.
[0047]According to the present invention, it is possible to avoid a situation where a block cannot be allocated for use by a communication terminal due to failure of reserving consecutive subcarriers, because communication terminals having different number of subcarriers composing the block are selected with a higher priority as simultaneously communicating terminals, and a block for use by the simultaneously communicating terminals is allocated within an available band. Accordingly, it becomes possible to flexibly allocate subcarriers.

Problems solved by technology

However, when performing subcarrier allocation with a very high degree of freedom as described above in a situation where many terminals are coexisting with subcarriers grouped into block(s) in varied sizes by SC-ASA system, selecting simultaneous access terminals by round-robin, Max CIR, or PF may cause a situation where some terminals cannot have a subcarrier allocated thereto.
This is because, although there must be as many consecutive unallocated subcarriers as the number of subcarriers included in a block when allocating subcarriers to a terminal which has to perform transmission with subcarriers grouped into block(s) due to various reasons such as position or power consumption mode of the terminal, there may arise a situation where it is impossible to reserve as many consecutive unallocated subcarriers as the block size, as allocation of subcarriers to each terminal proceeds, depending on the size of the block used by each terminal selected as a simultaneous access terminal and the position of the subcarrier selected by each terminal.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0097](First Embodiment)

[0098]A first embodiment exemplifies a specific case of applying the present invention to a situation where communication terminals (simply referred to as “terminals”, hereinafter) shown in table 1 are distributed within a cell. Here, it is assumed that all the terminals shown in table 1 perform uplink communication by SC-FDMA transmission, which performs spectrum allocation using SC-ASA (Single Carrier—Adaptive Spectrum Allocation).

[0099]As described above, the simultaneous access terminal selection (scheduling) method according to the present invention groups the terminals having the same block size of subcarriers to be used (value L of table 1), so that grouping such as shown in table 2 is performed first. In table 2, the terminals surrounded by dashed lines are defined as groups by the scheduling method according to the present invention, resulting in six groups here.

[0100]

TABLE 2Number ofBlockNumber ofsubcarriersTerminal IDsize (L)blocks(M)used (N)Group ...

second embodiment

[0127](Second Embodiment)

[0128]The scheduling method according to the first embodiment first selects simultaneous access terminals, and performs spectrum allocation to each of the selected simultaneous access terminals. When performing selection of simultaneous access terminals and spectrum allocation separately as described above, a spectrum having good channel condition may not necessarily be allocated to a selected terminal. This is because spectrum allocation to a terminal having a smaller block size is performed with a lower priority when performing spectrum allocation to the terminals in descending order of the block size, for example, and selection must be performed among the remaining spectra (that have not been selected for terminals having a higher priority of spectrum allocation). On the contrary, a scheduling method according to the second embodiment performs selection of simultaneous access terminals and spectrum allocation to the selected terminals at the same time.

[01...

third embodiment

[0143](Third Embodiment)

[0144]Although, in the scheduling method according to the first and the second embodiments, it is assumed that all the terminals in a cell perform uplink communication using SC-FDMA transmission (SC-ASA), a situation can also be conceived where terminals performing uplink communication using OFDM transmission coexist. In other words, spectrum allocation is flexible for a terminal located near the base station with sufficient battery level left because it does not have to consider PAPR characteristic so much, and further, higher frequency usage efficiency can be realized by using OFDM transmission to which technology such as adaptive modulation per subcarrier can be applied. The scheduling method according to a third embodiment therefore performs scheduling, considering the size of the subcarriers to be grouped into blocks in a situation where terminals performing SC-FDMA transmission coexist with terminals performing OFDM transmission.

[0145]FIG. 7 shows a con...

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PUM

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Abstract

Consecutive subcarriers are reserved, and the reserved consecutive subcarriers are properly allocated to a terminal. The invention is a scheduling method that allocates, within an available band, a block composed of one or more subcarriers and used for signal transmission by a communication terminal being a destination of communication, and the method includes the steps of selecting (S208), with a higher priority, communication terminals having different number of the subcarriers composing the block as simultaneously communicating terminals that perform signal transmission simultaneously, and allocating (S214) the block for use by the simultaneously communicating terminals within the available band.

Description

TECHNICAL FIELD[0001]The present invention relates to a scheduling method and a control station apparatus employed for a radio communication system that uses cellular radio system.BACKGROUND ART[0002]With the recent increase in the amount of data communication, there is a growing need for mobile communication systems having a higher efficiency of frequency usage, and various studies relating to one-cell reuse cellular systems in which all the cells employ the same frequency band are being conducted. In the E-UTRA (Evolved Universal Terrestrial Radio Access) system, which is one of the one-cell reuse cellular systems and under standardization by the 3GPP (3rd Generation Partnership Project), OFDMA (Orthogonal Frequency Division Multiple Access) system is being considered as the most promising candidate of down-link transmission system and SC-FDMA (Single Carrier Frequency Division Multiple Access) system as the most promising candidate of uplink transmission system (see, for example,...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): H04W72/00H04W24/00H04W36/00H04B7/00H04W4/00H04J3/00H04J1/00H04B7/208
Inventor TO, SHIMPEIHAMAGUCHI, YASUHIRONAMBA, HIDEOKUBOTA, MINORU
Owner SHARP KK