This application claims the benefit under 35 U.S.C. § 119(a) of a Korean patent application filed in the Korean Intellectual Property Office on Mar. 23, 2007 and assigned Serial No. 2007-28909, the entire disclosure of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a wireless mobile communication system. More particularly, the present invention relates to a system and method for transmitting/receiving resource allocation information in a wireless mobile communication system.
2. Description of the Related Art
An Institute of Electrical and Electronics Engineers (IEEE) 802.16 communication system is an example of a next generation communication system. As its name suggests, the IEEE 802.16 communication system uses the IEEE 802.16 standard.
The conventional IEEE 802.16 communication system uses an Uplink Media Access Protocol (UL-MAP) message and a Downlink Media Access Protocol (DL-MAP) message to provide UL and DL resource allocation information.
The DL-MAP message includes an Information Element (IE) defined in Table 1 below.
Using the information of table 1, regions of DL resources, e.g., DL data bursts, can be determined. Specifically, the DL resources can be expressed by the values of ‘Orthogonal Frequency Division Multiple Access (OFDMA) Symbol offset’, ‘Subchannel offset’, ‘No. OFDMA Symbols’ and ‘No. Subchannels’ that are included in Table 1.
Referring to
A description will be made of a conventional method for allocating data bursts in the data burst allocation region 130 of the DL sub-frame and for expressing the allocation information.
Allocation information of the allocated data bursts can be expressed using ‘OFDMA Symbol offset’, ‘Subchannel offset’, ‘No. OFDMA Symbols’ and ‘No. Subchannels’. Specifically, the point where ‘OFDMA Symbol offset’ is coincident with ‘Subchannel offset’ is a starting point of the allocated data burst. Furthermore, a two-dimensional rectangular data burst allocation region 140, which is composed of ‘No. OFDMA Symbols’ OFDMA symbols in the horizontal axis and ‘No. Subchannels’ subchannels in the vertical axis on the basis of the starting point, includes the data bursts that have been allocated.
A detailed description will now be made of four types of information used for expressing the data burst allocation information.
1. Expression of No. OFDMA Symbols
In the IEEE 802.16 communication system, the maximum number of OFDMA symbols included in one frame is 57. The ‘57’ is the sum of the allowable number of OFDMA symbols included in a DL sub-frame and the allowable number of OFDMA symbols included in a UL sub-frame. Therefore, the total number of OFDMA symbols included in the DL sub-frame should be less than 57. Thus, providing even 6 bits as the number of bits for representing positions and sizes of the DL data bursts is sufficient. The number of OFDMA symbols per frame proposed in the IEEE 802.16 communication system is as shown in Table 2 below.
2. Expression of No. Subchannels
The number of subchannels constituting a frame is subject to change according to the number of OFDMA subcarriers and a Fast Fourier Transform (FFT) size, as shown in Table 3.
As illustrated in Table 3, when the FFT size is at its maximum of 2048 (FFT size=2048), the number of subchannels is also at a maximum of 60. Accordingly, it is possible to express the number of subchannels with a maximum of 6 bits.
In the frame of
In the permutation zones, the number of subchannels and OFDMA symbols included in a DL slot is subject to change according to the permutation method used in the corresponding permutation zones, as follows. Here, the DL slot is the basic allocation unit for DL data bursts.
FUSC zone and Optional FUSC zone: 1 DL slot=1 subchannel ×1 OFDMA symbol
PUSC zone: 1 DL slot=1 subchannel ×2 OFDMA symbols
TUSC1 zone and TUSC 2 zone: 1 DL slot=1 subchannel ×3 OFDMA symbols
Band AMC zone:
For the Band AMC zone, 6 bins are used as the minimum unit for DL data burst allocation. In addition, 6 bins constitute one DL slot.
As described above, the number of bits necessary for expressing ‘Subchannel offset’ and ‘OFDMA Symbol offset’ is subject to change according to the FFT size and the permutation method.
3. Expression of Subchannel offset
For FFT size=2048, as the maximum number of subchannels is 60, 6 bits are needed for subchannel offset expression. However, for FFT size=128, as the maximum number of subchannels is 3, it is possible to sufficiently express the subchannel offset with 2 bits.
Even for the same FFT size, the number of bits for expressing the subchannel offset is subject to change according to the method of making the subchannel. That is, for the FUSC method, since the number of subchannels used for one DL slot is 1, 6 bits are needed to express the subchannel offset. However, for the Band AMC method, since the number of subchannels used for one DL slot is 3, 5 bits are needed to express the subchannel offset in order to indicate a maximum of 60/3=20.
The number of bits for expressing an OFDMA symbol offset is also subject to change according to the basic OFDMA symbol offset constituting one DL slot. For example, the number of bits necessary for expressing the OFDMA symbol offset is subject to change according to the FFT size and the permutation zone. Further, even in representing sizes of the subchannel and the OFDMA symbol, it is possible to variably determine the number of necessary bits according to the permutation zone.
As described above, the number of bits required for the ‘No. OFDMA Symbols’ field, the ‘No. Subchannels’ field, the ‘Subchannel offset’ field and the ‘OFDMA Symbol offset’ field constituting the DL-MAP IE is considerable. Accordingly, this considerable amount of data causes the occurrence of signaling overhead and a reduction in system performance.
An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a resource allocation information transmission/reception system and method for reducing signaling overhead in a wireless mobile communication system.
According to one aspect of the present invention, a system for transmitting/receiving resource allocation information in a wireless mobile communication system is provided. The system includes a transmission apparatus for allocating a data burst in a frame wherein the data burst is a two-dimensional region in a time domain and a frequency domain, and for transmitting resource allocation information on the allocated data burst, and a reception apparatus for receiving the resource allocation information from the transmission apparatus and for detecting a region of the frame where the data burst is allocated, using the received resource allocation information. The resource allocation information includes information on a start point and an end point of the data burst. The start point comprises a point which is spaced apart from a start point of the frame by a first offset value in the time domain, and is spaced apart from the start point of the frame by a second offset value in the frequency domain. The end point indicates a point which is spaced apart from the start point by a third offset value in the time domain, and is spaced apart from the start point by a fourth offset value in the frequency domain. The data burst is a two-dimensional rectangular region having a diagonal line segment connecting the start point to the end point.
According to another aspect of the present invention, a method for transmitting resource allocation information by a transmission apparatus in a wireless mobile communication system is provided. The method includes allocating a data burst in a frame wherein the data burst is a two-dimensional region in a time domain and a frequency domain and transmitting resource allocation information on the allocated data burst. The resource allocation information includes information on a start point and an end point of the data burst. The start point indicates a point which is spaced apart from a start point of the frame by a first offset value in the time domain, and is spaced apart from the start point of the frame by a second offset value in the frequency domain. The end point indicates a point which is spaced apart from the start point by a third offset value in the time domain, and is spaced apart from the start point by a fourth offset value in the frequency domain. The data burst is a two-dimensional rectangular region having a diagonal line segment connecting the start point to the end point.
According to further another aspect of the present invention, a method for receiving resource allocation information by a reception apparatus in a wireless mobile communication system is provided. The method includes receiving resource allocation information on a data burst and detecting a region where the data burst is allocated, from a frame which is a two-dimensional region in a time domain and a frequency domain, using the received resource allocation information. The resource allocation information includes information on a start point and an end point of the data burst. The start point indicates a point which is spaced apart from an start point of the frame by a first offset value in the time domain, and is spaced apart from the start point of the frame by a second offset value in the frequency domain. The end point indicates a point which is spaced apart from the start point by a third offset value in the time domain, and is spaced apart from the start point by a fourth offset value in the frequency domain.
Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
The above and other aspects, features and advantages of certain exemplary embodiments of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings in which:
Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features and structures.
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
Exemplary embodiments of the present invention provide a system and method for transmitting/receiving resource allocation information in a wireless mobile communication system. Although a description of the present invention will be made herein for a resource allocation information transmission/reception system and method in which data bursts are used as resources, this is to be understood as merely an example. That is, the resource allocation information transmission/reception system and method proposed by the present invention can be applied to any wireless mobile communication system that allocates a data burst region in a two-dimensional manner.
An exemplary embodiment of the present invention proposes a Downlink-Media Access Protocol (DL-MAP) Information Element (IE) as shown in Table 4.
1 bit
The DL-MAP IE shown in Table 4 uses Orthogonal Frequency Division Multiple Access (OFDMA)_Subchannel_Symbol_offset—1st and OFDMA_Subchannel_Symbol_offset—2nd in order to represent positions and sizes of DL data bursts. The two types of information each includes 12 bits, having a total of 24 bits of information. It can be appreciated that the 24-bit information is reduced from the conventional 27-bit information used for representing positions and sizes of DL data bursts with ‘OFMDA Symbol offset’, ‘Subchannel offset’, ‘No. OFDMA Symbols’ and ‘No. Subchannels’.
Each of the OFDMA_Subchannel_Symbol_offset—1st and the OFDMA_Subchannel_Symbol_offset—2nd has the format shown in Table 5.
Referring to
The OFDMA_Subchannel_Symbol_offset—1st indicates a relative position from the origin (start point) of the frame to a start point 205 of the two-dimensional rectangular data burst region. That is, the OFDMA_Subchannel_Symbol_offset—1st, in accordance with Table 5, can be represented as (x1, y1), and indicates an apex 205 which is spaced apart from a start point of the frame by x1 subchannels and apart from the start point of the frame by y1 OFDMA symbols. In the case of
Similarly, the OFDMA_Subchannel_Symbol_offset—2nd indicates a relative position from the start point 205 to an end point 207 of the two-dimensional rectangular data burst region. That is, the OFDMA_Subchannel_Symbol_offset—2nd can be represented as (x2, y2), and indicates an apex 207 which is spaced apart from the start point 205 by x2 subchannels and apart from the start point 205 by y2 OFDMA symbols. In the case of
Upon receiving a DL-MAP message including therein the OFDMA_Su bchannel_Symbol offset—1st and the OFDMA_Subchannel_Symbol_offset—2nd, a mobile station determines the start point of the region where its own data burst is allocated, based on the OFDMA_Subchannel_Symbol_offset—1st. Next, the mobile station determines the end point of the region where the data burst is allocated, depending on the OFDMA_Subchannel_Symbol_offset—2nd. That is, a size of the data burst allocation region is determined by subtracting an x1 value of OFDMA_Subchannel_Symbol_offset—1st from an x1+x2 value of OFDMA_Subchannel_Symbol_offset—2nd, and subtracting an y1 value of OFDMA_Subchannel_Symbol_offset—1st from an y1+y2 value of OFDMA_Subchannel_Symbol_offset—2nd.
The second exemplary embodiment, similar to the first exemplary embodiment, indicates a data burst allocation region using a start point and an end point of a two-dimensional data burst allocation region. However, the second exemplary embodiment can automatically determine the number of bits necessary for representing a subchannel offset and an OFDMA symbol offset between the start point and the end point according to the Fast Fourier Transform (FFT) size, the number of OFDMA symbols and the permutation method. A description will now be made of the parameters necessary for implementing the second embodiment.
1. No. OFDMA symbols: A parameter that the mobile station can determine depending on ‘No. OFDMA symbols’ or UL allocation start IE included in a DL-MAP message.
2. FFT size; Although it is a value previously agreed upon between a base station and a mobile station during system implementation, the mobile station may be able to determine another FFT size when interworking with the system having the foregoing another FFT size.
3. Max No. of Subchannels: The number of subchannels constituting a frame. Its value is determined as shown in Table 6 according to the bandwidth.
4. OFDMA Symbol_allocation_unit: A basic allocation unit for OFDMA symbols based on the permutation method. Its value is determined as shown in Table 7 according to the permutation method type. The mobile station receives OFDMA DL STC DL Zone IE to recognize the permutation method type and AMC type.
5. Subchannel_allocation_unit: A basic allocation unit for subchannels based on the permutation method. Its value is determined as shown in Table 8 according to the permutation method type. The mobile station receives OFDMA DL STC DL Zone IE to recognize permutation method type and AMC type.
As described above, it is possible to calculate the number of bits necessary for expressing an OFDMA symbol offset and a subchannel offset for each of the OFDMA_Subchannel_Symbol_offset—1st and the OFDMA_Subchannel_Symbol_offset—2nd according to the parameters the permutation method type.
First, the number of bits necessary for expressing the OFDMA symbol offset in each of the OFDMA_Subchannel_Symbol_offset—1st and the OFDMA_Subchannel_Symbol_offset—2nd can be calculated using Equation (1).
Next, the number of bits necessary for expressing the subchannel offset in each of the OFDMA Subchannel_Symbol_offset 1st and the OFDMA_Subchannel_Symbol_offset—2nd can be calculated using Equation (2).
Referring to
In step 304, the mobile station determines a start point of a two-dimensional data burst allocation region depending on the OFDMA_Subchannel_Symbol_offset—1st. In step 306, the mobile station determines an end point of the two-dimensional data burst allocation region depending on the OFDMA_Subchannel_Symbol_offset—2nd. In step 308, the mobile station determines the two-dimensional data burst allocation region having the start point and the end point. In step 310, the mobile station decodes a data burst located in the determined burst allocation region.
Referring to 4, in step 402, the base station determines a subchannel permutation method and system parameters. In step 404, the base station determines the number of bits necessary for expressing an OFDMA symbol offset between a start point and an end point of a two-dimensional data burst allocation region. In an exemplary implementation, the number of bits may be determined using Equation 1 above. In step 406, the base station determines the number of bits necessary for expressing a subchannel offset between the start point and the end point of the two-dimensional data burst allocation region. In an exemplary implementation, the number of bits may be determined using Equation 2 above. In step 408, the base station generates a DL-MAP IE corresponding to the calculated number of bits. In step 410, the base station transmits a DL-MAP message including the generated DL-MAP IE.
As is apparent from the foregoing description, exemplary embodiments of the present invention use a MAP message indicating two points of a two-dimensional data burst allocation region in the mobile communication system, thereby reducing the size of the MAP message and thus minimizing the signaling overhead.
While the invention has been shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
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2007-0028909 | Mar 2007 | KR | national |