[0001] 1. Field of the Invention
[0002] The present invention relates to a third generation mobile communication, and more particularly, to a method for generating and transmitting an optimal cell (base station) identification code using Hadamard code and bi-orthogonal code in a W-CDMA mobile communication system.
[0003] 2. Background of the Related Art
[0004] The Radio Access Network (RAN) standards of the Third Generation Partnership Project (3GPP) describes a Site Selection Diversity Transmit Power Control (SSDT). The SSDT, which is a selective macro diversity technique in a soft handover mode, allows a User Equipment (UE) to select one of cells in an active set called “Primary.” In this instance, all other cells are classed as “Non-primary.”
[0005] The main object of the SSDT is to transmit on the downlink from a primary cell, which reduces interference caused by multiple transmissions in a soft handover mode. A second object of the SSDT is to achieve fast site selection without intervention from networks such as UMTS Terrestrial Radio Access Network (UTRAN), thus maintaining an advantage of the soft handover. In order to select a primary cell, a temporary identification (ID) is assigned to every active cell having a transmission power level higher than a predetermined level, and the UE periodically informs a primary cell ID to other connected cells. In this instance, the UE receives, measures, an compares power levels of common pilots from the respective active cells to select the primary cell, which has the greatest pilot power. Thereafter, the UE cuts off powers from all other remaining cells which are non-primary cells.
[0006] Referring to
[0007] For reference, in
TABLE 1 channel channel number slot bit symbol bits bits of format rate rate per per Ndata #I kbps ksps SF frame slot bits 0 15 15 256 150 10 10 1 30 30 128 300 20 20 2 60 60 64 600 40 40 3 120 120 32 1200 80 80 4 240 240 16 2400 160 160 5 480 480 8 4800 320 320 6 960 960 4 9600 640 640
[0008]
TABLE 2 No. No. No. No. slot of of of of for- CH CH bits bits bits bits bits bits mat bit symbol per per of of of of #I rate rate SF frame slot N N N N 0 15 15 256 150 10 6 2 0 2 1 15 15 256 150 10 8 0 0 2 2 15 15 256 150 10 5 2 1 2 3 15 15 256 150 10 7 0 2 2 4 15 15 256 150 10 6 0 2 2 5 15 15 256 150 10 5 2 2 1
[0009] The NFBI, representing a number of bits per slot inserted in the FBI field, is used in a closed loop mode transmit diversity or SSDT, which requires feed back between access points of the UE and the UTRAN. As shown in
[0010] The operation of the SSDT for reducing interference caused by multiple transmission in the soft handover mode will next be explained in more detail.
[0011] In a soft handover mode, the SSDT is initially activated by UTRAN based on the cells in the active set, and thereafter the UTRAN of the SSDT option activated during a present soft handover period informs the cell and the UE. In this instance, a temporary ID is assigned to each active cell based on an order of the active set, and the assignment information on the IDs is given to the active cells and the UE. Thus, an active cell can identify its entry position in the active list, by which the ID code can also be determined. At the same time, the UE receives the active list and can assign ID codes of to active cells based on the order of entry of the cells on the list. Therefore, the UTRAN and the UE have corresponding information of the ID codes and the cells.
[0012] Moreover, the active list is renewed frequently and the renewed active list is provided to all active cells and the UE. After the SSDT and UE acknowledgement are activated, the UE starts to transmit the ID code of the primary cell, and the active cells start to detect primary cell ID information following a successful SSDT activation and admission of the UE acknowledgement.
[0013] The setting of temporary cell ID will next be explained.
[0014] A temporary ID is provided to cells during the SSDT for use as a site selection signal. In the SSDT mode, when an upper layer decides to make transmissions between a UE and a cell, the UE designates the most appropriate cell in the active cells as the primary cell and informs the UTRAN through the FBI field. Also, transmitting a signal to only one cell during the active SSDT mode can enhance a cell performance as intercellular interferences are reduced from the remaining other cells. The temporary cell ID is given as a binary bit sequence having a particular bit length, which is shown in Tables 3 and 4, below.
[0015] Table 3 shows temporary ID codes when the FBI is transmitted by one bit per slot, and Table 4 shows temporary ID codes when the FBI is transmitted by two bits per slot. As can be known from Tables 3 and 4, the temporary ID code may be in three forms of “Long,” “Medium,” and “Short,” and there can be 8 codes for each of the forms. The temporary ID codes are required to be transmitted within one frame. If the space for sending a given ID code cannot be obtained within a frame, i.e. the entire ID cannot be transmitted within a frame but must be split over two frames, the last bit(s) of the temporary ID code is (are) punctured. In Table 3 and 4 below, the bit(s) to be punctured in such cases are shown with brackets.
TABLE 3 ID code ID label Long Medium Short a 000000000000000 0000000(0) 00000 b 111111111111111 1111111(1) 11111 c 00000000111111 0000111(1) 00011 d 111111110000000 1111000(0) 11100 e 000011111111000 0011110(0) 00110 f 111100000000111 1100001(1) 11001 g 001111000011110 0110011(0) 01010 h 110000111100001 1001100(1) 10101
[0016] In Table 3, the long ID code with a code length 15 has a maximized minimum hamming distance d
TABLE 4 ID code ID label Long Medium Short a 0000000(0) 000(0) 000 0000000(0) 000(0) 000 b 1111111(1) 111(1) 111 1111111(1) 111(1) 111 c 0000000(1) 000(0) 000 1111111(1) 111(1) 111 d 1111111(1) 111(1) 111 0000000(0) 000(0) 000 e 0000111(1) 001(1) 001 1111000(0) 110(0) 100 f 1111000(0) 110(0) 110 0000111(1) 001(1) 011 g 0011110(0) 011(0) 010 0011110(0) 011(0) 010 h 1100001(1) 100(1) 101 1100001(1) 100(1) 101
[0017] In the Table 4, the long ID code with a code length 16 has a maximized minimum hamming distance d
[0018] The following Table 5 shows a number of times of site selection permitted to select a primary cell per one frame for different forms of ID codes, according to the temporary ID code characteristics shown in Tables 3 and 4.
TABLE 5 code a number of FBI bits assigned per slot for SSDT length 1 2 “Long” one site selection per two site selection per frame frame “Medium” two site selection per four site selection per frame frame “Short” three site selection per five site selection per frame frame
[0019] Referring to Table 5, if the number of FBI bits per slot is 1, the number of site selection per frame is one using a long ID code because 15 bits, one bit per slot, can be transmitted in each frame. If the number of FBI bits per slot is 2, the number of site selection per frame is two because 30 bits, two bits per slot, can be transmitted in each frame. Similarly, if the number of FBI bits per slot is 1, the number of site selection per frame is 2 using a medium ID code and 3 using a short ID code. Finally, if the number of FBI bits per slot is 2, the number of site selection per frame is 4 using a medium ID code and 5 using a short ID code.
[0020] Furthermore, when two bits of FBI are transmitted per slot, the 8 long ID codes of 14 bit lengths have a maximum cross-correlation value of “2” and a maximized minimum hamming distance 6 (d
[0021] As described before, when the UE assigns one of the temporary ID codes as the primary cell ID code and sends the primary cell ID code after the SSDT and the UE acknowledgement, the primary cell ID code is sent through the FBI field in the uplink control channel. Particularly, a cell is non-primary if the following three conditions are met, where NID is a length (a number of bits) of the generated temporary ID.
[0022] 1. The received primary ID code does not match with its own ID code;
[0023] 2. the received uplink signal quality satisfies a quality threshold defined by UTRAN; and
[0024] 3. the number of symbols punctured in the uplink compressed mode is smaller than └N
[0025] Otherwise, if any one of the above three conditions are not met, a cell is maintained as a primary cell.
[0026] The termination of the SSDT is determined by the UTRAN. Particularly, the UTRAN terminates the SSDT in a method identical to a procedure for terminating the soft handover, and informs the termination to all cells and the UE. Thus, in the related art SSDT, performance of cell ID code used for identifying respective cells is dependent on the maximum cross-correlation value or the maximized minimum hamming distance. Accordingly, an optimal cell ID code which has a maximum cross-correlation value or a maximized minimum hamming distance is required, and a method for identifying a cell using the optimal cell ID code is required.
[0027] Accordingly, the present invention is directed to a method for generating and transmitting optimal cell ID codes, that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
[0028] An object of the present invention is to provide a method for generating optimal cell Id codes for a soft handover.
[0029] Another object of the present invention is to provide a method for transmitting optimal cell ID codes for a soft handover.
[0030] Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
[0031] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a method for generating and transmitting optimal cell ID codes includes generating cell ID codes using Hadamard codes, which has first bit values of 0; and allocating the generated ID codes to cells which require ID codes.
[0032] In the above embodiment, the cell ID codes may be generated by either deleting or puncturing first bits of the Hadamard codes. The cell Id codes may be generated by either deleting or puncturing first and second bits of the Hadamard codes. The cell ID codes may also be generated by deleting first, second and sixth bits of the Hadamard codes.
[0033] In addition, the Hadamard codes in which the first bit of the second half of a code has a bit value of 0 is selected. Accordingly, the cell ID codes may be generated by either deleting or puncturing first bits of the selected Hadamard codes. The cell Id codes may be generated by either deleting or puncturing first and second bits of the selected Hadamard codes. The cell ID codes may also be generated by deleting first, second and sixth bits of the selected Hadamard codes.
[0034] A method for generating and transmitting optimal cell ID codes according to another embodiment of the present invention includes generating, at a UE, cell ID codes based on at least one of Hadamard codes or bi-orthogonal codes during an SSDT; respectively allocating the generated cell ID codes to active cells of the UE; periodically measuring, at the UE, received power levels of common pilots transmitted from the active cells to select a primary cell; and periodically transmitting ID codes of the selected primary cell to the active cells.
[0035] A still another method for generating and transmitting optimal cell ID codes according to the present invention includes allocating, at a UE, cell ID codes generated based on Hadamard codes during an SSDT to active cells; periodically measuring, at the UE, received power levels of common pilots transmitted from the active cells to select a primary cell; and periodically transmitting, at the UE, ID codes allocated to the selected primary cell to the active cells through a FBI field of an uplink control channel.
[0036] A further method for generating and transmitting optimal cell ID codes according to the present invention includes generating, at a UE, a plurality of cell ID codes based on Hadamard codes and bi-orthogonal codes during an SSDT; allocating the generated ID codes to active cells; periodically measuring, at the UE, received power levels of common pilots transmitted from the active cells to select a primary cell; and determining, at the UE, the number of bits which will be inserted into a FBI field of each slot when ID codes of the selected primary cell are transmitted to the active cells; repeating the ID codes of the primary cell selected by the UE among the generated ID codes by one or more number of times, depending on cell ID code types; and transmitting the ID codes to the active cells through an uplink control channel.
[0037] A still further method for generating and transmitting optimal cell ID codes according to the present invention includes selectively allocating, at a UE, one or more codes selected from cell ID codes based on Hadamard codes or bi-orthogonal codes depending on the number of active cells belonging to an active set of the UE, to the effective cells, repeating corresponding ID codes allocated by the UE by at least one or more number of times; and transmitting the ID codes to the active cells during the SSDT.
[0038] The invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein:
[0039]
[0040]
[0041]
[0042]
[0043]
[0044]
[0045]
[0046]
[0047]
[0048]
[0049]
[0050]
[0051]
[0052]
[0053] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. According to the present invention, temporary cell ID codes are generally generated using either the Hadamard codes or the bi-orthogonal codes, or both. Particularly, the Hadamard code is used in the first embodiment, both the Hadamard codes and the bi-orthogonal codes are used in the second embodiment, and either the Hadamard codes or the bi-orthogonal codes are used in the third embodiment depending upon a predetermined condition.
[0054] The first embodiment will first be explained. Temporary cell IDs are provided for each unit of a binary bit sequence having a specific bit code length, and temporary cell ID codes suggested in the first embodiment are shown in Tables 6 and 7 below. Namely, Table 6 shows temporary ID codes when the FBI is transmitted by one bit per slot, and Table 7 shows temporary ID codes when the FBI is transmitted by two bits per slot. According to the current 3GPP standards, the FBI is also used for data bit transmission in closed loop transmit diversity.
[0055] As can be known from Tables 6 and 7, there are three types or forms of temporary ID code, “Long,” “Medium,” and “Short.” Also, there can be 8 codes for each of the type. As in the related art, the temporary ID codes are required to be transmitted within one frame. However, if the space for sending a given ID code cannot be obtained within a frame, i.e. the ID code cannot be transmitted within a frame but must be split over two frames, the first bit or the first and second bits of the temporary ID code are punctured. In Tables 6 and 7 below, the bit(s) to be punctured in such cases are shown with brackets.
TABLE 6 Idenitifer Code Identifier Label Long Medium Short A 000000000000000 (0)0000000 00000 B 101010101010101 (0)1010101 10110 C 011001100110011 (0)0110011 01101 D 110011001100110 (0)1100110 11011 E 000111100001111 (0)0001111 00011 F 101101001011010 (0)1011010 10101 G 011110000111100 (0)0111100 01110 H 110100101101001 (0)1101001 11000
[0056]
TABLE 7 Identifier Code Identifier Label Long Medium Short A (0)0000000 (0)000 000 (0)0000000 (0)000 000 B (0)0000000 (0)000 000 (1)1111111 (1)111 111 C (0)1010101 (0)101 101 (0)1010101 (0)101 101 D (0)1010101 (0)101 101 (1)0101010 (1)010 010 E (0)0110011 (0)011 011 (0)0110011 (0)011 011 F (0)0110011 (0)011 011 (1)1001100 (1)100 100 G (0)1100110 (0)110 110 (0)1100110 (0)110 110 H (0)1100110 (0)110 110 (1)0011001 (1)001 001
[0057] Of the temporary Id codes shown in Tables 6, when one FBI bit per slot is transmitted, eight long ID codes with code lengths of 15 bits have a maximum cross correlation function value of “−1” and a maximized minimum Hamming distance value of 8 (d
[0058] Of the temporary ID codes shown in Table 7, when two FBI bits per slot is transmitted, eight long ID codes with code lengths of 14 bits have a maximum cross correlation function value of “0” and a maximized minimum Hamming distance value of 7 (d
[0059] A UE periodically measures received power levels of pilots transmitted by active cells of the UE, so that a cell having a received power level greater than a threshold value is selected as a primary cell. One of the-temporary ID codes is determined as a primary cell ID code to be periodically transmitted to active cells within an active set. The primary cell ID code is transmitted through the FBI field of an uplink control channel. At this time, the temporary ID codes are inserted into the FBI by 1 bit or 2 bits and transmitted.
[0060] In the first embodiment of the present invention, the temporary ID codes of Tables 6 and 7 are generated using the Hadamard codes of
[0061] A method for generating the temporary ID codes based on the Hadamard codes of
[0062] In the present invention, considering that the first bits of the Hadamard codes are all “0,” bits punctured at a transmitting party can be recognized in advance when the temporary ID codes generated by Table 6 or 7 are decoded by a receiving party. Thus, decoding gain is obtained.
[0063] The temporary ID codes corresponding to a case where one FBI per slot is transmitted as shown in Table 6 are generated as follows. In this case, the first bit of each Hadamard code is either deleted or punctured considering that the first bit of each Hadamard code is “0.” This is because there is no reduction of the Hamming distance for a set temporary ID code. Hereinafter, the temporary ID code will be called an ID code.
[0064] The eight long ID codes having a code length of 15 bits are generated by deleting the first bit of the Hadamard codes having a code length of 16 bits.
[0065] The eight medium ID codes having a code length of 7 bits are generated using the Hadamard codes having a code length of 8 bits. However, the code length that can be inserted and transmitted by each frame is 15 bits. Thus, for each frame, the medium ID codes can be repeated twice and transmitted. Since the ID codes generated by repeating twice the Hadamard codes of 8 bits exceeds the number of bits that can be transmitted per frame by 1 bit, the ID codes are transmitted after puncturing the first bit of one of the Hadamard codes of 8 bits as shown in Table 6.
[0066] The eight short ID codes having a code length of 5 bits are generated by deleting the first bit, the fifth bit, and the eight bit of the Hadamard codes having a code length of 8 bits. In this case, since the ID codes have a code length of 15 bit that can be transmitted per frame, the eight short ID codes generated by deleting 3 bits of the Hadamard codes of 8 bits are repeated three times and transmitted. Also, in the present invention, other short ID codes generated by deleting 3 bits of the Hadamard codes of 8 bits can be used. These short ID codes will be described later.
[0067] The temporary ID codes corresponding to a case where two FBI per slot is transmitted as shown in Table 7 are generated as follows. Since the first bits of the Hadamard codes are all “0,” the first bit of each Hadamard code is either deleted or punctured. Also, since the FBI is transmitted at bits per slot, the number of ID bits that can be transmitted per frame is 30 bits.
[0068] The eight long ID codes having a code length of 14 bits are generated using the Hadamard codes having a code length of 16 bits. In this case, since the number of bits that can be inserted and transmitted in one frame is 30 bits, the Hadamard codes of 16 bits can be repeated twice. However, if the Hadamard codes of 16 bits is repeated twice, the number of bits that can be transmitted per frame is exceeded by 2 bits. Accordingly, the ID codes are transmitted after puncturing the first bits of the first column (first and second bits of the Hadamard code bits) from one of the repeated Hadamard codes of 16 bits as shown in Table 7.
[0069] The eight medium ID codes having a code length of 6 bits are generated using Hadamard codes having a code length of 8 bits. In this case, since code length that can be inserted and transmitted by one frame is code length of 30 bits, the medium ID codes based on the Hadamard codes of 8 bits can repeat four times. However, the medium ID codes based on the Hadamard codes of 8 bits exceed the number of bits that can be transmitted per frame, by 2 bits when repeated four times. Accordingly, the ID codes are transmitted after puncturing the first bits of the first column (the first and second bits) from one of the repeated Hadamard codes of 8 bits as shown in Table 7.
[0070] The eight short ID codes having a code length of 6 bits are generated by deleting a pair of bits, i.e. the first bits of the first column (first and second bits), from the Hadamard codes having a code length of 8 bits.
[0071] As discussed above, upon activating acknowledgment of the SSDT and the UE, the UE determines one of the temporary ID codes as a primary cell ID code. Thus, the primary cell ID code is periodically transmitted to the active cells within the active set through the FBI field of the uplink control channel. Furthermore, in the present invention, other temporary ID codes are suggested as shown in Table 8.
[0072] Table 8 shows temporary ID codes corresponding to a case where the temporary ID codes are inserted one FBI bit per slot and transmitted.
TABLE 8 Identifier Code Identifier Label Long Medium Short A 000000000000000 (0)0000000 00000 B 101010101010101 (0)1010101 11111 C 011001100110011 (0)0110011 00011 D 110011001100110 (0)1100110 11100 E 000111100001111 (0)0001111 00110 F 101101001011010 (0)1011010 11001 G 011110000111100 (0)0111100 01010 H 110100101101001 (0)1101001 10101
[0073] The temporary ID codes of Table 8 differ from those of Table 6 in the short ID codes. In other words, under the current 3GPP standards, when the FBI is transmitted by 1 bit per slot, the short ID codes have an optimized cross correlation value of “2.” Accordingly, the short ID codes existing in the related art can be used. Particularly, the eight short ID codes of Table 8 is generated by deleting the first, fifth, and eighth bits of the Hadamard codes having a code length of 8 bits. However, in addition to these eight short ID codes having of 5 bit code lengths, other short ID codes generated by deleting three bits from Hadamard codes of 8 bits may be used. Tables 9, 10 and 11 show other short ID codes.
TABLE 9 Hadarmad code having code length of 8 Position of column of bit Short identifier code having code length of 5 1 2 3 4 5 6 7 8 4 5 6 7 8 3 5 6 7 8 3 4 6 7 8 3 4 5 7 8 3 4 5 6 8 3 4 5 6 7 2 5 6 7 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 0 1 0 1 0 1 1 0 1 0 1 0 0 1 0 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 0 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 0 0 1 1 1 0 0 0 0 0 0 1 1 0 1 1 0 0 1 1 0 0 0 1 1 0 1 0 1 1 0 1 0 1 1 0 1 0 0 1 0 1 0 0 1 0 1 0 0 1 1 1 0 1 1 0 0 0 0 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 1 1 1 1 0 1 0 1 1 0 1 0 1 1 0 1 0 0 1 0 1 0 0 1 0 1 0 0 1 1 1 0 0 1 1 0 0 0 1 1 0 1 1 1 0 1 0 0 0 1 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 1 0 1 1 1 1 0 0 1 1 0 0 0 1 1 0 1 0 0 1 0 1 0 0 1 1 1 0 0 1 1 0 0 0 1 1 0 1 0 1 1 0 1 0 1 1 0 1 0 0 1 1 0 0 1
[0074]
TABLE 10 Hadarmad code having code length of 8 Position of column of bit Short identifier code having code length of 5 1 2 3 4 5 6 7 8 2 4 6 7 8 2 4 5 7 8 2 4 5 6 8 2 4 5 6 7 2 3 6 7 8 2 3 5 7 8 2 3 5 6 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 0 1 1 1 1 0 1 1 1 0 0 1 1 1 0 1 1 1 1 0 1 0 1 0 1 0 1 1 0 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 1 0 1 0 1 1 0 1 0 0 1 0 1 0 0 1 0 1 0 1 1 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 1 1 0 1 0 0 1 0 1 0 0 1 0 1 0 0 1 1 1 1 1 1 0 1 1 0 1 0 1 1 0 1 0 0 0 0 0 1 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 1 0 1 1 0 1 0 1 1 0 1 0 1 1 1 1 0 1 1 1 0 0 1 1 1 0 1 1 0 0 1 0 1 0 1 1 0 1 0 1 0 0 0 0 1 1 1 1 0 0 0 1 1 0 0 0 1 1 0 0 0 1 1 1 0 0 1 1 1 0 0 1 1 0 0 0 1 1 0 0 0 1 1 1 0 0 1 1 0 1 0 0 1 1 0 0 0 1 1 0 1 0 1 1 0 1 0 1 1 0 1 0 0 1 1 0 0 1 1 1 1 0 1 1 1 1 0 1
[0075]
TABLE 11 Hadarmad code having code length of 8 Position of column of bit Short identifier code having code length of 5 1 2 3 4 5 6 7 8 2 3 5 6 7 2 3 4 7 8 2 3 4 6 8 2 3 4 6 7 2 3 4 5 8 2 3 4 5 7 2 3 4 5 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 0 1 1 0 0 1 0 1 0 1 0 1 1 0 1 1 1 1 0 1 1 0 1 0 1 0 1 1 0 1 0 0 1 0 1 0 1 0 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 1 1 0 1 1 0 1 0 1 1 0 1 0 1 1 0 1 0 1 1 0 1 0 1 1 0 0 0 1 1 0 0 1 1 0 1 1 0 1 1 1 1 0 1 0 1 1 0 1 0 1 1 0 1 1 1 1 0 0 0 1 1 0 0 1 1 1 0 0 1 0 0 0 0 1 1 1 1 0 0 1 1 1 0 0 0 1 1 0 0 0 1 1 0 0 0 1 1 0 0 0 1 1 0 0 0 1 1 0 0 0 1 1 0 1 0 1 1 0 1 0 1 0 1 0 1 1 0 1 1 0 1 0 1 0 0 1 0 1 0 1 1 0 1 1 0 1 0 1 1 1 1 0 1 1 0 0 0 1 1 1 1 0 0 1 1 1 0 0 0 1 1 0 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 1 0 1 1 0 1 0 0 1 1 1 1 0 0 1 1 0 0 1 1 1 0 0 1 1 1 0 0 0 1 1 0 1 1 1 1 0 1 0 1 1 0 1 0
[0076] The short ID codes shown in Tables 9, 10 and 11 are generated to have a code length of 5 bits by deleting the first bits of the Hadamard codes having a code length of 8 bits and then deleting 2 other bits in 21 patterns.
[0077] In other words, each of the short ID codes having a code length of 5 bits, as shown in Table 9, is generated by deleting 3 bits of position patterns (1,2,3), (1,2,4), (1,2,5), (1,2,6), (1,2,7), (1,2,8), and (1,3,4) from the eight Hadamard codes of 8 bits. The short ID codes having a code length of 5 bits shown in Table 10 are generated by deleting 3 bits of position patterns (1,3,5), (1,3,6), (1,3,7), (1,3,8), (1,4,5), (1,4,6), and (1,4,7) from the eight Hadamard codes of 8 bits. Finally, the short ID codes having a code length of 5 bits shown in Table 11 are generated by deleting 3 bits of position patterns (1,4,8), (1,5,6), (1,5,7), (1,5,8), (1,6,7), (1,6,8), and (1,7,8) sequentially from the eight Hadamard codes of 8 bits.
[0078] In the present invention, a portion of the short ID codes shown in Table 9, those generated by deleting the first and second bits of the Hadamard codes of 8 bits, is used. That is, the short ID codes having a code length of 5 bits, generated by deleting 3 bits in the six position patterns (1,2,3), (1,2,4), (1,2,5), (1,2,6), (1,2,7), and (1,2,8), are used.
[0079] In generating the short ID codes of 5 bits or 6 bits using the Hadamard codes of 8 bits, the ID codes can be generated by a common deletion pattern of deleting the first bits and the second bits to insert and transmit 1 bit or 2 bits into the FBI field per slot. Thus, the hardware which will be used for decoding at the receiving party can be obtained simply. Thus, 21 short ID codes having a code length of 5 bits are generated and have the same maximized minimum Hamming distance. Accordingly, it is noted that the 21 short ID codes have the same performance result for AWGN channel. This will be apparent from
[0080] However, in the evaluation of a fading channel, the 21 short ID codes have different performances depending on Doppler frequencies, as shown in
TABLE 12 Identifier Code Identifier Label Long Medium Short A 000000000000000 (0)0000000 00000 B 101010101010101 (0)1010101 01001 C 011001100110011 (0)0110011 11011 D 110011001100110 (0)1100110 10010 E 000111100001111 (0)0001111 00111 F 101101001011010 (0)1011010 01110 G 011110000111100 (0)0111100 11100 H 110100101101001 (0)1101001 10101
[0081] In Table 12, the deletion position pattern (1,2,6) for generating the short ID codes of 5 bits is applicable to a case where the ID codes are inserted into the FBI field 2 bits per slot. Accordingly, both case in which the ID codes are inserted into the FBI field 1 bit per slot and the case in which the ID codes are inserted into the FBI field 2 bits per slot have similarity in the deletion patterns, thereby obtaining decoding gain.
[0082] The results of performance evaluation according to the first embodiment of the present invention will now be described.
[0083]
TABLE 13 case where FBI per slot is 1 bit case where FBI per slot is 2 bit AWGN long medium medium short long long medium medium short Channel (15) (8) (7) (5) (16) (14) (8) (6) (6) Conventional 0 0 0 0 0 0 0 0 0 Present 0.3 −0.1 0.7 0.25 0 −0.2 −0.1 0.8 0.8 Invention
[0084]
TABLE 14 case where FBI per slot is 1 bit case where FBI per slot is 2 bit AWGN long medium medium short long long medium medium short Channel (15) (8) (7) (5) (16) (14) (8) (6) (6) Conventional 0 0 0 0 0 0 0 0 0 Present 1.5 0 1.0 1.5 1.0 1.3 −0.2 2 2 Invention
[0085] In first embodiment, the temporary ID codes may be used during the SSDT. The temporary ID codes may also be used when the UE desires to transmit its own cell data to the UTRAN. In this case, the temporary ID codes can be optimized for the cross correlation characteristics and the Hamming distance.
[0086] The second embodiment of the present invention will next be explained. Temporary cell IDs are provided for each unit of a binary bit sequence having a specific bit code length, and temporary cell ID codes suggested in the second embodiment are shown in Tables 15 and 16 below. Namely, Table 15 shows temporary ID codes when the FBI is transmitted by one bit per slot, and Table 16 shows temporary ID codes when the FBI is transmitted by two bits per slot.
[0087] As can be known from Tables 15 and 16, there are three types or forms of temporary ID code, “Long,” “Medium,” and “Short.” Also, there can be 8 codes for each of the type. As in the related art, the temporary ID codes are required to be transmitted within one frame. However, if the space for sending a given ID code cannot be obtained within a frame, i.e. the ID code cannot be transmitted within a frame but must be split over two frames, bit(s) of the temporary ID code are punctured. In Tables 15 and 16 below, the bit(s) to be punctured in such cases are shown with brackets.
TABLE 15 Identifier Identifier Code Label long medium(8) medium(7) short A 000000000000000 00000000 0000000 00000 B 101010101010101 11111111 1010101 10010 C 011001100110011 01010101 0110011 01001 D 110011001100110 10101010 1100110 11011 E 000111100001111 00110011 0001111 00111 F 101101001011010 11001100 1011010 10101 G 011110000111100 01100110 0111100 01110 H 110100101101001 10011001 1101001 11100
[0088] In Table 15, long ID codes having a code length of 15 bits, which are generated by deleting the first bit from Hadamard codes having a code length of 16 bits, have a maximized minimum Hamming distance value of 8 (d
TABLE 16 Identifier Code Identifier (columns and rows request slot position and FBI bit position) Label long(16) long(14) medium(8) medium(6) short A 00000000 0000000 0000 000 000 00000000 0000000 0000 000 000 B 11111111 0000000 1111 000 000 11111111 1111111 1111 111 111 C 00000000 1010101 0000 101 101 11111111 1010101 1111 101 101 D 11111111 1010101 1111 101 101 00000000 0101010 0000 010 010 E 01010101 0110011 0101 011 011 01010101 0110011 0101 011 011 F 10101010 0110011 1010 011 011 10101010 1001100 1010 100 100 G 01010101 1100110 0101 110 110 10101010 1100110 1010 110 110 H 10101010 1100110 1010 110 110 01010101 0011001 0101 001 001
[0089] In Table 16, long ID codes having a code length of 16 bits based on bi-orthogonal codes having a code length of 16 bits have a maximized minimum Hamming distance value of 8 (d
[0090] The temporary ID codes of the present invention, as shown in Tables 15 and 16, are generated based on the Hadamard codes having code lengths of 8 bits and 16 bits as shown in
[0091] In
[0092] The eight upper Hadamard codes having a code length of 16 bits have a bit value of 0 in the ninth bits. Accordingly, the minimum Hamming distance is not affected by the Hadamard codes even though the ninth bits are punctured as the case where the first bits are punctured. Thus, in the present invention, the long ID codes having a code length of 14 bits, generated by deleting the first bit and the ninth bit of the Hadamard codes having a code length of 16 bits, are also used as shown in Table 17 and will be described later.
[0093] In
[0094] Therefore, in the present invention, to generate eight medium ID codes having a code length of 8 bits when the FBI per slot is 1 bit, and to generate eight medium ID codes having a code length of 8 bits when the FBI per slot is 2 bits, the bi-orthogonal codes having a code length of 8 bits as shown in
[0095] A method for generating SSDT ID codes based on the Hadamard codes and the bi-orthogonal codes to maximize the minimum Hamming distance will be described below.
[0096] In the method for generating SSDT ID codes based on the Hadamard codes, it is considered that the first bits of the Hadamard codes having code lengths of 8 bits and 16 bits are all “0.” Thus, even if the SSDT ID codes generated by puncturing the first bits of the Hadamard codes are transmitted, the minimum Hamming distance is maintained without being reduced. Moreover, in the method for generating SSDT ID codes based on the bi-orthogonal codes, it is considered that the bi-orthogonal codes having a code length of 8 bits or 16 bits are more useful than the Hadamard codes having the same code length as that of the bi-orthogonal codes in view of minimum Hamming distribution.
[0097] First, the method for generating the ID codes in case where the FBI per slot is 1 bit will be described.
[0098] Eight long ID codes having a code length of 15 bits are generated by deleting the first bits of eight Hadamard codes having a code length of 16 bits. In this case, the minimum Hamming distance has a maximum value of 8. Eight medium ID codes having a code length of 8 bits are generated using eight bi-orthogonal codes having a code length of 8 bits. In this case, the minimum Hamming distance has a maximum value of 4. Eight medium ID codes having a code length of 7 bits are generated by deleting the first bit of eight Hadamard codes having a code length of 8 bits. In this case, the minimum Hamming distance has a maximum value of 4.
[0099] Eight short ID codes having a code length of 5 bits are generated by deleting the first bits of eight Hadamard codes having a code length of 8 bits and then deleting optional two other bits. In this case, deletion bit patterns as shown in Tables 9, 10 and 11 of the first embodiment may be used, and the minimum Hamming distance has a maximum value of 2.
[0100] Among the 21 deletion position patterns in Tables 9, 10 and 11, when the first, second, and sixth bits of the eight Hadamard codes having a code length of 8 bits are deleted to generate the eight short ID codes, an optimal performance can be obtained. Furthermore, in the present invention, as some short ID codes of Table 9, the first and second bits of the Hadamard codes having a code length of 8 bits are deleted and then the other 1 bit is deleted in six patterns such as position patterns (1,2,3) (1,2,4) (1,2,5) (1,2,6) (1,2,7) (1,2,8) such that the short ID codes having a code length of 5 bits are generated.
[0101] In generating the ID codes of 5 bits or 6 bits by deleting the first and second bits of the Hadamard codes of 8 bits, the ID codes can be generated by a common deletion pattern by deleting the first bits and the second bits to insert 1 bit or 2 bits into the FBI field per slot. Thus, hardware which will be used for decoding at the receiving party can be obtained simply.
[0102] The method for generating the ID codes in case where the FBI per slot is 2 bits will be described.
[0103] Eight long ID codes having a code length of 16 bits are generated using eight bi-orthogonal codes having a code length of 16. In this case, the minimum Hamming distance has a maximum value of 8. Eight long ID codes having a code length of 14 bits are generated by deleting the first and second bits of the Hadamard codes having a code length of 16 bits. In this case, the minimum Hamming distance has a maximum value of 7.
[0104] Eight medium ID codes having a code length of 8 bits are generating using eight bi-orthogonal codes having a code length of 8 bits. In this case, the minimum Hamming distance has a maximum value of 4. Eight medium ID codes having a code length of 6 bits are generated by deleting the first and second bits of eight Hadamard codes having a code length of 8 bits. In this case, the minimum Hamming distance has a maximum value of 3. Eight short ID codes having a code length of 6 bits are also generated by deleting the first and second bits of the eight Hadamard codes having a code length of 8 bits. In this case, the minimum Hamming distance is 3.
[0105] In the present invention, when the FBI per slot is 2 bits, the SSDT ID codes generated by puncturing the first and second bits of the eight Hadamard codes having a code length of 16 bits can additionally be used, as shown in Table 17.
TABLE 17 Identifier Code Identifier (columns and rows request slot position and FBI bit position) Label long(16) long(14) medium(8) medium(6) short A 00000000 0000000 0000 000 000 00000000 0000000 0000 000 000 B 11111111 1111000 1111 000 000 11111111 0001111 1111 111 111 C 00000000 0101101 0000 101 101 11111111 1010101 1111 101 101 D 11111111 1010101 1111 101 101 00000000 1011010 0000 010 010 E 01010101 0011011 0101 011 011 01010101 0110011 0101 011 011 F 10101010 1100011 1010 011 011 10101010 0111100 1010 100 100 G 01010101 0110110 0101 110 110 10101010 1100110 1010 110 110 H 10101010 1001110 1010 110 110 01010101 1101001 0101 001 001
[0106] In Table 17, the long ID codes having a code length of 14 bits are generated by deleting the first bit and the ninth bit of the Hadamard codes having a code length of 16 bits, and have a maximized minimum Hamming distance value of 8 (d
[0107] A UE periodically measures received power levels of pilots transmitted by active cells of the UE, so that a cell having a received level greater than a threshold value is selected as a primary cell. One of the temporary ID codes is determined as a primary cell ID code to be periodically transmitted to active cells within an active set. The primary cell ID code is transmitted through the FBI field of an uplink control channel. At this time, the temporary ID codes are inserted into the FBI by 1 bit or 2 bits and then transmitted, and the number of the bits of the ID codes which will be inserted into the FBI field per slot is determined by the UE.
[0108] The transmission procedure of the generated SSDT ID codes will be described.
[0109] In
[0110] In
[0111] In
[0112]
[0113] In
[0114] In
[0115] In
[0116] The results of performance evaluation according to the second embodiment of the present invention will next be described.
TABLE 18 case where FBI per slot is 1 bit case where FBI per slot is 2 bit AWGN long medium medium short long long medium medium short Channel (15) (8) (7) (5) (16) (14) (8) (6) (6) Conventional 0 0 0 0 0 0 0 0 0 present 0.3 0 0.7 0.25 0 0.25 0 0.8 0.8 invention
[0117] The performance gain of Table 18 is obtained based on the SSDT ID codes having a code length 14 bits generated by deleting the first and second bits of the Hadamard codes having a code length of 16 bits, in case where the FBI per slot is 2 bits. To complement the performance gain of Table 18, the performance gain of Table 19 is obtained based on the long ID codes having a code length of 14 bits generated by deleting the first bit and the ninth bit of the Hadamard codes having a code length of 16 bits as shown in Table 17.
TABLE 19 case where FBI per slot is 1 bit case where FBI per slot is 2 bit AWGN long medium medium short long long medium medium short Channel (15) (8) (7) (5) (16) (14) (8) (6) (6) Conventional 0 0 0 0 0 0 0 0 0 present 0.3 0 0.7 0.25 0 0.3 0 0.8 0.8 invention
[0118]
TABLE 20 case where FBI per slot is 1 bit case where FBI per slot is 2 bit AWGN long medium medium short long long medium medium short Channel (15) (8) (7) (5) (16) (14) (8) (6) (6) Conventional 0 0 0 0 0 0 0 0 0 present 1.5 1.0 1.0 1.5 1.2 1.3 0.8 2.0 2.0 invention
[0119] The performance gain of Table 20 is obtained based on the SSDT ID codes having a code length 14 bits generated by deleting the first and second bits of the Hadamard codes having a code length of 16 bits, in case where the FBI per slot is 2 bits. To complement the performance gain of Table 20, the performance gain of Table 21 is obtained based on the long ID codes having a code length of 14 bits generated by deleting the first bit and the ninth bit of the Hadamard codes having a code length of 16 bits as shown in Table 17.
TABLE 21 case where FBI per slot is 1 bit case where FBI per slot is 2 bit AWGN long medium medium short long long medium medium short Channel (15) (8) (7) (5) (16) (14) (8) (6) (6) Conventional 0 0 0 0 0 0 0 0 0 present 1.5 1.0 1.0 1.5 2.2 2.2 0.8 2.0 2.0 invention
[0120] In the second embodiment, the temporary ID codes may be used during the SSDT. The temporary ID codes may also be used when the UE desires to transmit its own cell data to the UTRAN. In this case, the temporary ID codes can be optimized for the cross correlation characteristics and the Hamming distance.
[0121] The third embodiment of the present invention will now be explained. Temporary cell IDs are provided for each unit of a binary bit sequence having a specific bit code length, and temporary cell ID codes suggested in the third embodiment are shown in Tables 22 and 23 below. Namely, Table 22 shows temporary ID codes when the FBI is transmitted by one bit per slot, and Table 22 shows temporary ID cedes when the FBI is transmitted by two bits per slot.
[0122] As can be known from Tables 22 and 23, there are three types or forms of temporary ID code, “Long,” “Medium,” and “Short.” Also, there can be 8 codes