WO2011024475A2

WO2011024475A2 - Assignment map group size indication in case of fractional frequency reuse

Info

Publication number: WO2011024475A2
Application number: PCT/JP2010/005302
Authority: WO
Inventors: Lei Huang; Isamu Yoshii
Original assignee: Panasonic Corporation
Priority date: 2009-08-27
Filing date: 2010-08-27
Publication date: 2011-03-03
Also published as: WO2011024475A3

Abstract

In accordance with a first aspect of the present invention, there is provided a method of indicating the size of Assignment MAP (A-MAP) for resource assignment in a multiple access mobile communications system, wherein A-MAP comprises of a plurality of A-MAP information elements (IEs) which are grouped into a predefined number of A-MAP groups, said method comprising the step of setting the value of a signaling field which indicates the A-MAP size according to the actual number of A-MAP IEs in each A-MAP group, and a predefined A-MAP group size indication look-up table; and inserting an additional signaling in a first A-MAP group to indicate the sizes of unoccupied resources in remaining A-MAP groups if the value of the signaling field does not exactly indicate the actual number of A-MAP IEs in any an A-MAP group.

Description

ASSIGNMENT MAP GROUP SIZE INDICATION IN CASE OF FRACTIONAL FREQUENCY REUSE

The present invention pertains to the field of an assignment MAP group size indication in case of a fractional frequency reuse.

Institute of Electrical and Electronics Engineers (IEEE) 802.16 Working Group is developing a new air interface specification, i.e., IEEE 802.16m, to meet the requirements of International Mobile Telecommunications - Advanced (IMT-Advanced) next generation mobile systems. This means that IEEE 802.16m needs to support data rates of up to approximately 100 Mbps for high mobility (up to 250 km/s) and up to approximately 1 Gbps for low mobility.

To support low, medium and high data rates, IEEE 802.16m uses scalable bandwidths, including 5, 7, 8.75, 10, and 20 MHz. IEEE 802.16m also uses Orthogonal Frequency Division Multiple Access (OFDMA) as the multiple access schemes in the downlink (DL) and uplink (UL), which can provide multiplexing operation of data streams from multiple users onto the time and frequency resources.

OFDMA is based on Orthogonal Frequency Division Multiplexing (OFDM) technique that subdivides the bandwidth into multiple frequency subcarriers. In an OFDM system, the input data stream is divided into several parallel sub-streams of reduced data rate (thus increased symbol duration) and each sub-stream is modulated and transmitted on a separated orthogonal subcarrier. The increased symbol duration improves the robustness of OFDM to channel delay spread. Furthermore, the introduction of the cyclic prefix (CP) can completely eliminate inter-symbol interference as long as the CP duration is longer than the channel delay spread. In addition, OFDM modulation can be realized with efficient Inverse Fast Fourier Transform (IFFT), which enables a large number of subcarriers with low complexity. In an OFDM system, resources are available in the time domain by means of OFDM symbols and in the frequency domain by means of subcarriers. Note that as for detailed OFDMA parameters in an IEEE 802.16m mobile system, please refer to NPL1.

Similar to other prevailing mobile communications systems such as 3^rd Generation Partnership Project (3GPP) - Long-Term Evolution (LTE), an IEEE 802.16m mobile system is also based on cellular concept. A cell in an IEEE 802.16m mobile system generally comprises of a Base Station (BS) and a plurality of Mobile Stations (MSs).

A block diagram illustrating an exemplary MS 10 in an IEEE 802.16m mobile system is shown in Figure 1. The MS 10 comprises of a controller 12, a message generator 14, a message processor 16, and an OFDMA transceiver 18.

With reference to Figure 1, the controller 12 is a Media Access Control (MAC) protocol controller, which controls general MAC protocol operations. The message generator 14 generates UL control signaling or data under the control of the controller 12. For example, the message generator 14 may generate a bandwidth request signaling when the MS attempts to transmit UL data.

The message processor 16 analyzes DL control signaling received from the BS under the control of the controller 12, and provides its analysis result to the controller 12. For example, resource assignment information for DL data transmission to a MS and for UL data transmission of a MS to the BS may be derived from the received DL control signaling.

The OFDMA transceiver 18 includes a encoder/decoder for encoding/decoding a bit-stream at a corresponding encoding rate, an OFDM modulator/demodulator for transforming an OFDM symbol to/from subcarrier data by using an IFFT/FFT operation, a Digital-to-Analog Converter (DAC)/Analog-to-Digital Converter (ADC) for converting an analog/digital signal to a digital/analog signal and an RF processor for transforming a base-band signal to/from an RF signal.

A block diagram illustrating an exemplary BS 20 in an IEEE 802.16m mobile system is shown in Figure 2. The BS 20 comprises a controller 22, a scheduler 24, a message generator 26, a message processor 28, and an OFDMA transceiver 29.

With reference to Figure 2, the controller 22 is a MAC protocol controller, which controls general MAC protocol operations. The scheduler 24 schedules the allocation of resources to the MSs under the control of the controller 22. The message generator 26 receives resource allocation scheduling information from the scheduler 24 and then generates data or DL control signaling. The DL control signaling contains resource assignment information for DL data transmission and UL data transmission, etc. The message processor 28 analyzes the UL control signaling received from a plurality of MSs under the control of the controller 22 and reports its analysis result to the controller 22. The OFDMA transceiver 29 has the same functionality as the OFDMA transceiver 18 in Figure 1.

In an IEEE 802.16m mobile system, radio transmission is organized in the hierarchy of superframe, frame and subframe. Each 20 ms superframe is divided into four 5 ms frames. For 5, 10 or 20 MHz bandwidth, each 5 ms frame further consists of eight 0.617 ms subframes when CP is 1/8 or 1/16 of useful OFDMA symbol time. Each subframe is assigned for either DL or UL transmission. There are three types of subframes for 5, 10, and 20 MHz bandwidth:
Type-1 subframe consists of six OFDMA symbols,
Type-2 subframe consists of seven OFDMA symbols, and
Type-3 subframe consists of five OFDMA symbols.

Figure 3 is a diagram of illustrating the structure of an exemplary IEEE 802.16m Time Division Duplex (TDD) frame 30 with a 4:4 DL-to-UL ratio and CP = 1/8 of useful OFDMA symbol time. The frame 30 comprises of four

DL subframes

32, 34, 36, and 38, and four

UL subframes

42, 44, 46, and 48. Note that the last DL subframe 38 is a Type-3 subframe; and other DL/UL subframes are Type-1 subframes. In addition, there exist a Transmit/receive Transition Gap (TTG) 39 for DL/UL switch between the last DL subframe 38 and the first UL subframe 42, and a Receive/transmit Transition Gap (RTG) 49 for UL/DL switch following the last UL subframe 48.

With reference to Figure 3, the four

MAPs

31, 33, 35, 37 are located at four

DL subframes

32, 34, 36, and 38, respectively. Note that the

MAPs

31, 33, 35, 37, carry unicast service control information, which is generated by the message generator 26 as shown in Figure 2. In case of Transmission Time Interval (TTI) of one subframe, the MAP 31 is responsible for providing unicast service control in DL subframe 32 and UL subframe 42. The MAP 33 is in charge of providing unicast service control in DL subframe 34 and UL subframe 44. The MAP 35 is responsible for providing unicast service control in DL subframe 36 and UL subframe 46. The MAP 37 is in charge of providing unicast service control in DL subframe 38 and UL subframe 48.

It should be noted that in the first DL subframe 32 of frame 30, there also exists a preamble (not shown in Figure 3) for timing, frequency, and frame synchronization, etc. Furthermore, if the DL subframe 32 is the first subframe of a superframe, in addition to MAP 31 and preamble, a Superframe Header (SFH) may also exist in the DL subframe 32, which carries basic system parameters and system configuration information, e.g., superframe number, BS Identifier (ID), and duplex mode, etc.

Figure 4 illustrates the structure of an exemplary IEEE 802.16m Fractional Frequency Reuse (FFR) Type-1 DL subframe 50. The DL subframe 50 comprises of two frequency partition (FP) zones, i.e., reuse-1 FP zone 51 and reuse-3 FP zone 61. The reuse-1 FP zone 51 comprises of only a FP, i.e., FP(0) 53. The reuse-3 FP zone 61 comprises of three FPs, i.e., FP(1) 63, FP(2) 65, and FP(3) 67. Among these three FPs in the reuse-3 FP 61, FP(2) 65 is of highest power. Note that FP(0) 53, FP(1) 63, FP(2) 65, and FP(3) 67 are indexed from the lowest Logical Resource Unit (LRU) index to the highest LRU index, where LRU is the basic logical unit for resource allocation with a size of 18 subcarriers ' 6 OFDMA symbols for Type-1 subframe, and the number of LRUs per subframe is 96 for 20 MHz bandwidth.

Generally, in case of FFR, the cell center users are scheduled to the reuse-1 FP, i.e., FP(0) 53, and the cell edge users are scheduled to the highest-power reuse-3 FP, i.e., FP(2) 65. Since the highest-power reuse-3 FP is different among neighboring cells, and the cell center is the area closer to a BS that is particularly immune to co-channel interference, FFR technique is able to maximize spectral efficiency for cell center users and improves signal strength and throughput for cell edge users.

With reference to Figure 4, both FP(0) 53 and FP(2) 65 contain a MAP region. The MAP region in FP(0) 53 comprises of Non-User Specific MAP (NUS-MAP) 52, and a first part of Assignment MAP (A-MAP) 54, etc. The MAP region in FP(2) 65 comprises of a second part of A-MAP 62. The NUS-MAP 52 includes information required to decode the first part of A-MAP 54 and the second part of A-MAP 62.

The first part of A-MAP 54 and the second part of A-MAP 62 carry resource assignment information, which comprises of a plurality of A-MAP information elements (IEs) (not shown in Figure 4), each of which is encoded separately. The A-MAP IEs are categorized into multiple types, e.g.,
DL/UL Basic Assignment MAP IE used for resource assignment in the DL/UL;
DL/UL Group Configuration MAP IE used for assignment of an MS to a group in the DL/UL; and
DL/UL Group Resource Allocation MAP IE used for allocation of resources to MSs within a group in the DL/UL, etc.

Each A-MAP IE is also inclusive of a Cyclic Redundancy Code (CRC) with a predefined length (e.g., 16 bit), which is masked by a certain kind of ID, according to the A-MAP IE type. For example, for DL/UL Basic Assignment MAP IE and DL/UL Group Configuration MAP IE, the CRC is masked by a Station ID, which uniquely identifies a MS within the domain of a BS, while DL/UL Group Resource Allocation MAP IE is masked by a Group ID, which uniquely identifies a group of MSs within the domain of a BS. Note that MS can obtain its own Station ID during network entry or re-entry, and can also obtain its own Group ID by decoding the DL/UL Group Configuration MAP IE if it is assigned to a group. Table 1 shows an exemplary DL Basic Assignment MAP IE.

With reference to Figure 4, A-MAP IEs are grouped into three A-MAP groups, i.e., A-MAP Group 1 55, A-MAP Group 2 57, and A-MAP Group 3 62, based on Modulation and Coding Schemes (MCS) and FP zones. A-MAP IEs in the A-MAP Group 1 55 are transmitted in FP(0) 53 with the MCS of Quadrature Phase-Shift Keying (QPSK) 1/4; A-MAP IEs in the A-MAP Group 2 57 are transmitted in FP(0) 53 with the MCS of QPSK 1/2; and A-MAP IEs in the A-MAP Group 3 62 are transmitted in FP(2) 65 with the MCS of QPSK 1/2. The number of A-MAP IEs in each A-MAP group is indicated in the NUS-MAP 52 via the signaling field "A-MAP size" 58.

Generally, MS can only decode its own A-MAP IEs according to its own IDs (e.g., Station ID, Group ID, etc). After channel decoding of an A-MAP IE, if CRC check with one of its own IDs is successful, MS recognizes that this is its own A-MAP IE. Otherwise MS does not know whether this is an A-MAP IE or data. This is so-called "blind detection". In other words, for the purpose of terminating blind detection at the end of the first part of A-MAP 54 and the second part of A-MAP 62, MS needs to decode the NUS-MAP 52 first to capture the number of A-MAP IEs in each A-MAP group. Otherwise MS operates blind detection even in the data channel 56 of FP(0) 53 and the data channel 64 of FP(2) 65.

In the prior art NPL2, the following design principles are used for A-MAP group size indication:
One A-MAP IE size (e.g., 56 bits) is supported. Note that an A-MAP IE with the MCS of QPSK 1/2 occupies 1 MAP Logical Resource Unit (MLRU) and an A-MAP IE with the MCS of QPSK 1/4 occupies 2 MLRUs.
The maximum number of MLRUs for A-MAP is 48 per subframe, which is about 25% of subframe resource at 20MHz bandwidth.
A single 8-bit lookup table is used for all 5, 10, and 20 MHz bandwidths.

Since the number of A-MAP group size combinations for 20 MHz bandwidth can be as large as 10725, a 14-bit look-up table is required for full signaling of A-MAP group size. As a result, in order to implement an 8-bit look-up table, 10469 out of 10725 group size combinations have to be removed.

In the prior art NPL2, a two-step procedure is used for group size combination removal. At the first step, the granularities of A-MAP Group 1 55, A-MAP Group 2 57, and A-MAP Group 3 62 are constricted according to the following criterion:
N₁ may be (0:2:24);
N₂ may be (0:4:48);
N₃ may be (0:5:48);
wherein N₁ is the number A-MAP IEs of A-MAP Group 1 55; N₂is the number of A-MAP IEs in A-MAP Group 2 57; and N₃ is the number of A-MAP IEs in A-MAP Group 3 62. This results that the number of group size combinations is reduced from 10725 to 346. At the second step, the number of group size combinations is further reduced from 346 to 256 by approximately uniform removal of 90 out of 346 remaining group size combinations.

It should be pointed out that after the two-step group size combination removal in the prior art, A-MAP Group 1 55 have two granularities, i.e., the size of two A-MAP IEs and the size of four A-MAP IEs. In addition, A-MAP Group 2 57 has a better granularity than A-MAP Group 3 62.

IEEE 802.16m-09/0034, IEEE 802.16m System Description Document (SDD) IEEE C802.16m-09/1356r1, A-A-MAP group size indication in non-user specific A-MAP IE

In the prior art, an 8-bit A-MAP group size indication look-up table is used instead of a 14-bit look-up table. This means that the number of A-MAP IEs in an A-MAP group may not be exactly indicated. In case of non-exact indication, BS has to over-indicatethe number of A-MAP IEs in an A-MAP group, which would incur unoccupied resource in that group.

Figure 5 illustrates the structure of an exemplary IEEE 802.16m FFR Type-1 DL subframe 70 in case of non-exact A-MAP group size indication. With reference to Figure 5, if the value of "A-MAP Size" field 80 in the NUS-MAP 84 is not perfectly matched to the actual number of A-MAP IEs in the A-MAP Group 1 72, there exists unoccupied resource 73 in A-MAP Group 1 72. Similarly, if the value of "A-MAP Size" field 80 in the NUS-MAP 84 does not exactly indicate the actual number of A-MAP IEs in the A-MAP Group 2 74 and the actual number of A-MAP IEs in the A-MAP Group 3 82, there also exist unoccupied resource 77 in A-MAP Group 2 74 and unoccupied resource 83 in A-MAP Group 3 82.

Note that since unoccupied resource 77 of A-MAP Group 2 74 is adjacent to data channel 76 of FP(0) 78, and unoccupied resource 83 of A-MAP Group 3 82 is adjacent to data channel 86 of FP(2) 88, BS can allocate them for data transmission, and they are not wasted. However, since unoccupied resource 73 of A-MAP Group 1 72 is too small for data and not adjacent to data channel 76 of FP(0) 78, BS cannot allocate it for data transmission. Therefore, unused resource 73 of A-MAP group 1 72 is wasted.

Furthermore, in addition to normal blind detection on occupied resource 71 of A-MAP Group 1 72, occupied resource 75 of A-MAP Group 2 74, and occupied resource 81 of A-MAP Group 3 82, MS also needs to operate blind detection in unoccupied resource 73 of A-MAP Group 1 72, unoccupied resource 77 of A-MAP Group 2 74, and unoccupied resource 83 of A-MAP Group 3 82. This results in extra blind detection, which would increase processing time and power consumption of MS. Therefore, there exists a need of developing an efficient method of A-MAP group size indication to reduce the number of extra blind detection in case of non-exact indication.

In accordance with a first aspect of the present invention, there is provided a method of indicating the A-MAP size for resource assignment in a multiple access mobile communications system, wherein A-MAP comprises of a plurality of A-MAP IEs which are grouped into a predefined number of A-MAP groups, said method comprising the step of setting the value of a signaling field which indicates the A-MAP size according to the actual number of A-MAP IEs in each A-MAP group, and a predefined A-MAP group size indication look-up table; and inserting an additional signaling in a first A-MAP group to indicate the sizes of unoccupied resources in remaining A-MAP groups if the value of the signaling field does not exactly indicate the actual number of A-MAP IEs in any an A-MAP group.

In accordance with a first aspect of the present invention, the additional signaling may be inserted into the unoccupied resource of the first A-MAP group in a form of broadcast A-MAP IE if the value of the signaling field does not exactly indicate the actual number of A-MAP IEs in the first A-MAP group. A CRC is calculated based on the content of the broadcast A-MAP IE, masked by a broadcast identifier, and appended to the end of the broadcast A-MAP IE.

In accordance with a first aspect of the present invention, the additional signaling may be carried in a broadcast A-MAP IE in the occupied resource of the first A-MAP group. The additional signaling carried in the broadcast A-MAP IE may also indicate the size of unoccupied resource of the first A-MAP group. The broadcast A-MAP IE carrying additional signaling may also carry the resource allocation information for broadcast MAC messages. A CRC is calculated based on the content of the broadcast A-MAP IE, masked by a broadcast identifier, and appended to the end of the broadcast A-MAP IE;

In accordance with a first aspect of the present invention, the predefined A-MAP group size indication look-up table may be optimized by adjusting the granularity of the first A-MAP group so that the granularity of the first A-MAP group is always the size of two A-MAP IEs. The predefined A-MAP size look-up table may also be optimized by adjusting the granularities of the remaining A-MAP groups so that the A-MAP groups in reuse-3 frequency partition have a better granularity than the A-MAP groups in reuse-1 frequency partition.

In accordance with a second aspect of the present invention, there is provided a method of indicating the A-MAP size for resource assignment in a multiple access mobile communications system, wherein A-MAP comprises of a plurality of A-MAP IEs which are grouped into a predefined number of A-MAP groups, said method comprising the step of setting the value of a signaling field which indicates the A-MAP size according to the actual number of A-MAP IEs in each A-MAP group, and a predefined A-MAP group size indication look-up table; and inserting an additional signaling in a first A-MAP group to indicate the actual number of A-MAP IEs in remaining A-MAP groups if the value of the signaling field does not exactly indicate the actual number of A-MAP IEs in any an A-MAP group.

These and other features and advantages of the present invention will be better understood with reference to the following detailed description of the present invention, along with the accompanying figures, and appended claims.

The invention can avoid extra blind detection in MS, so that the processing time and power consumption of MS can be reduced.

Figure 1 shows a block diagram illustrating an exemplary MS in an IEEE 802.16m mobile system. Figure 2 shows a block diagram illustrating an exemplary BS in an IEEE 802.16m mobile system. Figure 3 shows a diagram illustrating the structure of an exemplary IEEE 802.16m TDD frame with a 4:4 DL-to-UL ratio and CP = 1/8 of useful OFDMA symbol time. Figure 4 shows a diagram illustrating the structure of an exemplary IEEE 802.16m FFR Type-1 DL subframe. Figure 5 shows a diagram illustrating the structure of an exemplary IEEE 802.16m FFR Type-1 DL subframe in case of non-exact A-MAP group size indication. Figure 6 shows a flowchart illustrating a method of A-MAP group size indication in accordance with a first embodiment of the present invention. Figure 7 shows a diagram illustrating the operation of the method as shown in Figure 6. Figure 8 shows a flowchart illustrating a method of A-MAP group size indication in accordance with a second embodiment of the present invention. Figure 9 shows a diagram illustrating the operation of the method as shown in Figure 8. Figure 10 shows a flowchart illustrating a method of A-MAP group size indication in accordance with a third embodiment of the present invention.

Description of Embodiment

With reference to Figure 5, it can be observed that all of unoccupied resource 73 of A-MAPGroup 1 72, unoccupied resource 77 of A-MAP Group 2 74, and unoccupied resource 83 of A-MAP Group 3 82 incur extra blind detection; and but only unoccupied resource 73 of A-MAP Group 1 72 causes resource waste. Furthermore, since the granularity of A-MAP Group 1 72 is at least the size of two A-MAP IEs, unoccupied resource 73 of A-MAP Group 1 72 can accommodate at least one A-MAP IE if it is present. In addition, MS generally decodes A-MAP Group 1 72, A-MAP Group 2 74, and A-MAP Group 3 82 in sequence.

Inspired by the above observations, a basic spirit of the present invention is to insert an additional signaling into unoccupied resource 73 of A-MAP Group 1 72 to indicate the size of unoccupied resource 77 of A-MAP Group 2 74 and unoccupied resource 83 of A-MAP Group 3 82 so that MS can avoid extra blind detection in A-MAP Group 2 74 and A-MAP Group 3 82.

Various embodiments of the present invention will now be described in detail with reference to the annexed drawings. In the following description, a detailed description of known functions and configurations incorporate herein has been omitted for clarity and conciseness.

(First Embodiment)
Figure 6 illustrates a method 200 of A-MAP group size indication according to the first embodiment of the present invention. Figure 7 illustrates the operation of method 200 shown in Figure 6.

With reference to Figure 6 and Figure 7, the method 200 starts the Step 202. At Step 204, the value of "A-MAP Size" field 110 in the NUS-MAP 114 is set according to the actual number of A-MAP IEs in A-MAP Group 1 102, A-MAP Group 2 104, and A-MAP Group 3 112, and a predefined A-MAP group size indication look-up table. An exemplary A-MAP group size indication look-up table is shown in Table 2. Note that the number of A-MAP IEs in a A-MAP group indicated by the "A-MAP Size" field 110 in the NUS-MAP 114 should be larger than the actual number of A-MAP IEs in that group in case of non-exact indication.

At Step 206, BS determines whether the value of "A-MAP Size" 110 in the NUS-MAP 114 exactly indicates the actual number of A-MAP IEs in the A-MAP Group 1 102 or not. If the value of "A-MAP Size" field 110 is perfectly matched to the actual number of A-MAP IEs in the A-MAP Group 1 102, this means that there is no unoccupied resource in A-MAP Group 1 102. Then the method 200 stops at Step 210.

If the value of "A-MAP Size" field 110 does not exactly indicate the actual number of A-MAP IEs in the A-MAP Group 1 102, this means that there exists unoccupied resource 103 in A-MAP Group 1 102. At Step 208, an appropriately designed Additional Signaling MAP IE 117 is inserted into unoccupied resource 103 in A-MAP Group 1 102 to indicate the size of unoccupied resource 107 in A-MAP Group 2 104 and the size of unoccupied resource 113 in A-MAP Group 3 112. Alternatively, the Additional Signaling MAP IE 117 can be used to indicate the actual number of A-MAP IEs in A-MAP Group 2 104 and the actual number of A-MAP IEs in A-MAP Group 3 112. After that, the method 200 stops at Step 210.

Table 3 shows an exemplary design of Additional Signaling MAP IE 117. Note that MS can recognize Additional Signaling MAP IE 117 by checking "MAP IE Type" field. The size of unoccupied resource 107 in A-MAP Group 2 104 and the size of unoccupied resource 113 in A-MAP Group 3 112 indicated in Additional Signaling MAP IE 117 are actually equivalent to the number of extra blind detections in A-MAP Group 2 104 and A-MAP Group 3 112, respectively. In addition, a CRC (e.g., 16 bits) needs to be generated based on the content of Additional Signaling MAP IE 117. The CRC also needs to be masked by a broadcast ID so that each MS connected to the BS can decode Additional Signaling MAP IE 117. Note that the broadcast ID may be a well known Station ID reserved for broadcast connection.

According to the first embodiment of the present invention, once MS decodes an Additional Signaling MAP IE 117 in A-MAP Group 1 102, it can avoid extra blind detection in A-MAP Group 2 104 and A-MAP Group 3 112. So the processing time and power consumption of MS can be reduced.

In addition, it would be better to locate Additional Signaling A-MAP IE 117 at the beginning of unused resource 103 of A-MAP Group 1 102. This is because MS can know the boundary of A-MAP Group 1 102 after decoding Additional Signaling MAP IE 117, and then stop blind detection in A-MAP Group 1 102. As a result, the number of extra blind detection in A-MAP Group 1 102 is reduced to one even if unoccupied resource 103 of A-MAP Group 1 102 has a size of more than one A-MAP IE.

According to the first embodiment of the present invention, the predefined A-MAP group size indication look-up table can be optimized by considering granularity balance among A-MAP Group 1 102, A-MAP Group 2 104, and A-MAP Group 3 112. For example, A-MAP Group 1 102 may always have the best granularity, i.e., the size of two A-MAP IEs, for accommodating Additional Signaling MAP IE 117. A-MAP Group 3 112 may have the second best granularity because MS in reuse-3 FP may not be able to decode Additional Signaling MAP IE 117 in A-MAP Group 1 102. So, it is better to reduce unoccupied resource 113 in A-MAP Group 3 112 for the purpose of reducing extra blind detection in A-MAP Group 3 112. A-MAP Group 2 104 may have the worst granularity thanks to Additional Signaling MAP IE 117 in A-MAP Group 1 102.

According to the first embodiment of the present invention, in addition to normal blind detections in occupied resource 101 of A-MAP Group 1 102, MS also needs to operate undesired blind detections in unoccupied resource 103 of A-MAP Group 1 102. For reducing processing time and power consumption of MS, it would be better for MS to avoid the undesired blind detections in unused resource 103 of A-MAP Group 1 102.

(Second Embodiment)
Figure 8 illustrates a method 300 of A-MAP group size indication according to a second embodiment of the present invention. Figure 9 illustrates the operation of method 300 shown in Figure 8.

With reference to Figure 8 and Figure 9, the method 300 starts the Step 302. At Step 304, the value of "A-MAP Size" field 160 in the NUS-MAP 164 is set according to the actual number of A-MAP IEs in A-MAP Group 1 152, A-MAP Group 2 154, and A-MAP Group 3 162, and a predefined A-MAP group size indication look-up table, as shown in Table 2. At Step 306, BS determines whether a broadcast MAC message, e.g., PGID info, AAI-TRF-IND, and AAI-PAG-ADV, is scheduled to be transmitted in the data channels of DL subframe 150. If no any broadcast MAC message is scheduled to be transmitted in the data channels of DL subframe 150, then the method 300 stops at Step 310.

If there is a broadcast MAC message scheduled to be transmitted in data channels of DL subframe 150, at Step 308, a Broadcast Message MAP IE 167 is inserted into occupied resource 151 in A-MAP Group 1 152 to indicate the size of unoccupied resource 153 in A-MAP Group 1 152, the size of unoccupied resource 157 in A-MAP Group 2 154, and the size of unoccupied resource 163 in A-MAP Group 3 162. Alternatively, Broadcast Message MAP IE 167 can be used to indicate the actual number of A-MAP IEs in A-MAP Group 1 152, in A-MAP Group 2 154, and in A-MAP Group 3 162. After that, the method 300 stops at Step 310.

Table 4 shows an exemplary design of Broadcast Message MAP IE 167. In addition to normal resource allocation information for broadcast MAC messages, Broadcast Message MAP IE 167 is also used to carry additional signaling to indicate the size of unoccupied resource 153 in A-MAP Group 1 152, the size of unoccupied resource 157 in A-MAP Group 2 154, and the size of unoccupied resource 163 in A-MAP Group 3 162. Note that a CRC (e.g., 16 bits) needs to be generated based on the content of Broadcast Message MAP IE 167, and the CRC also needs to be masked by a broadcast ID so that each MS connected to the BS can decode Broadcast Message MAP IE 167.

According to the second embodiment of the present invention, if Broadcast Message MAP IE 167 with URI = 1 is always placed at the end of occupied resource 153 of A-MAP Group 1 152, it is not necessary to include "UR-G1" field in Broadcast Message MAP IE 167 to indicate the size of unoccupied resource 153 in A-MAP Group 1 152. This is because MS can know the boundary of occupied resource 153 of A-MAP Group 1 152 after decoding Broadcast Message A-MAP IE 167 with URI = 1, and then stop blind detection before unoccupied resource 151 in A-MAP Group 1 152 is reached.

According to the second embodiment of the present invention, since MS is able to recognize additional signaling by normal blind decoding in occupied resource 151 of A-MAP Group 1 152, undesired blind decoding in unoccupied resource 153 of A-MAP Group 1 152 is no longer required if Broadcast Message MAP IE 167 is present in A-MAP Group 1 151.

(Third Embodiment)
Figure 10 illustrates a method 400 of A-MAP group size indication according to the third embodiment of the present invention. With reference to Figure 10, the method 400 starts the Step 402. At Step 404, the value of "A-MAP Size" field in the NUS-MAP is set according to the actual number of A-MAP IEs in A-MAP Group 1, A-MAP Group 2, and A-MAP Group 3, and a predefined A-MAP group size indication look-up table.

At Step 406, BS determines whether a broadcast MAC message, e.g., PGID info, AAI-TRF-IND, and AAI-PAG-ADV, is scheduled to be transmitted in the data channels of relevant DL subframe. If a broadcast MAC message is scheduled to be transmitted in data channels of relevant DL subframe, at Step 412, a Broadcast Message MAP IE as shown in Table 4 is inserted into occupied resource of A-MAP Group 1 to indicate the sizes of unoccupied resources in A-MAP Group 1, A-MAP Group 2, and A-MAP Group 3. After that, the method 400 stops at Step 414.

At Step 406, If no any broadcast MAC message is scheduled to be transmitted in the data channels of relevant DL subframe, then at Step 408, BS determines whether the value of "A-MAP Size" field in the NUS-MAP exactly indicates the actual number of A-MAP IEs in the A-MAP Group 1 or not. If the value of "A-MAP Size" field in the NUS-MAP exactly indicates the actual number of A-MAP IEs in the A-MAP Group 1, this means that there is no unoccupied resource in A-MAP Group 1. Then the method 400 stops at Step 414.

At Step 408, if the value of "A-MAP Size" field in the NUS-MAP does not exactly indicate the actual number of A-MAP IEs in the A-MAP Group 1, this means that there exists unoccupied resource in A-MAP Group 1. At Step 410, an Additional Signaling MAP IE as shown in Table 3 is inserted into unoccupied resource of A-MAP Group 1 to indicate the sizes of unoccupied resources in A-MAP Group 2 and A-MAP Group 3. After that, the method 400 stops at Step 414.

It will be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects to be illustrative and not restrictive.

The disclosure of Japanese Patent Application No. 2009-196941, filed on August 27, 2009, including the specification, drawings and abstract, is incorporated herein by reference in its entirety.

Claims

A method of indicating the size of assignment MAP (A-MAP) for resource assignment in a multiple access mobile communications system, wherein A-MAP comprises of a plurality of A-MAP information elements (IEs) which are grouped into a predefined number of A-MAP groups, said method comprising the step of:
setting the value of a signaling field which indicates the A-MAP size according to the actual number of A-MAP IEs in each A-MAP group, and a predefined A-MAP group size indication look-up table; and
inserting an additional signaling in a first A-MAP group to indicate the sizes of unoccupied resources in remaining A-MAP groups if the value of the signaling field does not exactly indicate the actual number of A-MAP IEs in any an A-MAP group.
The method according to claim 1, wherein the additional signaling may be inserted into the unoccupied resource of the first A-MAP group in a form of broadcast A-MAP IE if the value of the signaling field does not exactly indicate the actual number of A-MAP IEs in the first A-MAP group.
The method according to claim 2, wherein a Cyclic Redundancy Code (CRC) is calculated based on the content of the broadcast A-MAP IE, masked by a broadcast identifier, and appended to the end of the broadcast A-MAP IE.
The method according to claim 1, wherein the additional signaling may be carried in a broadcast A-MAP IE in the occupied resource of the first A-MAP group.
The method according to claim 1 and claim 4, wherein the broadcast A-MAP IE carrying additional signaling may also carry the resource allocation information for broadcast MAC messages.
The method according to claim 1 and claim 4, wherein additional signaling carried in the broadcast A-MAP IE may also indicate the size of unoccupied resource of the first A-MAP group.
The method according to claim 4, wherein a CRC is calculated based on the content of the broadcast A-MAP IE, masked by a broadcast identifier, and appended to the end of the broadcast A-MAP IE.
The method according to claim 1, wherein the predefined A-MAP group size indication look-up table may be optimized by adjusting the granularity of the first A-MAP group so that the granularity of the first A-MAP group is always the size of two A-MAP IEs.
The method according to claim 1, wherein the predefined A-MAP group size indication look-up table may be optimized by adjusting the granularities of the remaining A-MAP groups so that the A-MAP groups in reuse-3 frequency partition have a better granularity than the A-MAP groups in reuse-1 frequency partition.
A method of indicating the size of assignment MAP (A-MAP) for resource assignment in a multiple access mobile communications system, wherein A-MAP comprises of a plurality of A-MAP information elements (IEs) which are grouped into a predefined number of A-MAP groups, said method comprising the step of
setting the value of a signaling field which indicates the A-MAP size according to the actual number of A-MAP IEs in each A-MAP group, and a predefined A-MAP group size indication look-up table; and,
inserting an additional signaling in a first A-MAP group to indicate the actual number of A-MAP IEs in remaining A-MAP groups if the value of the signaling field does not exactly indicate the actual number of A-MAP IEs in any an A-MAP group.