[0037] The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, but not to be construed as a limitation of the present invention.
[0038] The present invention proposes a spatial division multiple access method for an indoor distributed system, comprising the following steps: a base station receives an uplink signal sent by a terminal, and performs channel estimation according to the uplink signal; The terminal determines the belonging of the antenna; the base station divides the terminals belonging to different antennas into the same SDMA group, and allocates the same radio resources for data transmission.
[0039] According to the current situation of the relevant SDMA technology introduced in the background section, the description of the SDMA scheme in the existing LTE technology is based on the allocation method of pilot frequencies, and the SDMA technology is realized by allocating different pilot frequencies to users. When the pilot resource allocation is completed, the channel estimation on the base station side of multiple terminals communicating using the same pilot resource will fall within the same detection window, so that multiple users cannot be distinguished.
[0040] The invention is based on the characteristics of the indoor distributed system. When there is a large isolation between floors and the coverage areas of each channel are relatively independent, multiple users are reasonably grouped to perform SDMA communication, which will effectively improve the system performance.
[0041] like figure 1 As shown, it is a flowchart of a method for spatial division multiple access of an indoor distributed system proposed by the present invention, including the following steps:
[0042] S101: The base station receives the uplink signal sent by the terminal, and performs channel estimation.
[0043] When the allocation of pilot frequency resources is completed, the channel estimation on the base station side of multiple terminals communicating using the same pilot frequency resources will fall within the same detection window, so that multiple users cannot be distinguished. For example, for the TDD HSUPA system, when the Midamble code is allocated in the default allocation method, the pilot resource used by the user and the code channel resource used by the user are bound. If there are slots, code channels and frequency resources, the same pilot resources will inevitably be used, which will cause the channel estimates of multiple users to fall within the same channel estimation window. In this way, it is impossible to judge which antenna the user belongs to. Therefore, the present invention proposes that the base station can perform channel estimation through other channels sent by the terminal, thereby judging which antenna the terminal belongs to.
[0044] For example, the base station determines the antenna belonging of the user according to the channel estimation of the DPCH (Dedicated Physical Channel, Dedicated Physical Channel) channel accompanying the uplink. The DPCH channel accompanying the uplink is shared by each user, or a DPCH channel is allocated to each user. When each user shares the DPCH channel by time division, different user terminals use the channel in different time slots, or each user uses the code division method to realize that each user terminal occupies one DPCH channel. Correspondingly, the base station performs multi-antenna channel estimation according to the signal on the DPCH of the corresponding time slot allocated to the terminal or the signal of the corresponding DPCH channel, and obtains the channel estimation information of each user terminal.
[0045] For example, the base station can obtain the spatial covariance matrix of each user according to the multi-antenna channel estimation of the DPCH accompanying each user's uplink. For each user, the base station obtains the shaping coefficient w corresponding to each antenna through the EBB algorithm (k，ka) , k=1...K, ka=1...Ka, where K, Ka respectively represent the total number of users and the total number of antenna elements, since the amplitude of the shaping coefficient of each user corresponding to each antenna reflects the The amplitude of the received signal on each antenna is determined, therefore, the corresponding home antenna of the user can be determined by the amplitude of the shaping coefficient.
[0046] S102: According to the result of the channel estimation, the base station determines the antenna belonging of the terminal.
[0047] After performing multi-antenna channel estimation on the user terminal according to step S101, for example, the base station obtains the terminal's spatial covariance matrix according to the multi-antenna channel estimation of the terminal's DPCH, and for each terminal, the base station uses the EBB beamforming algorithm to obtain each The shaping coefficients w corresponding to the antennas (k，ka) , k=1...K, ka=1...Ka, where K, Ka represent the number of terminals and the number of antenna units respectively, when |w (k，ka) | 2 Γ, the base station judges that the terminal k belongs to the antenna ka, otherwise it considers that the terminal k does not belong to the antenna ka, where Γ is the discrimination threshold set by the system. The setting of Γ can be set according to the actual operation of the system. For example, increasing or decreasing the value of Γ will reduce or increase the number of home antennas of the user terminal.
[0048] S103: The base station groups the terminals, and allocates the same radio resources to the terminals belonging to the same group for data transmission.
[0049] By judging the attribution of the terminal antenna in step S102, the information of which users are effectively received or transmitted on which antennas can be obtained. Therefore, user terminals belonging to different antennas have a large degree of isolation from each other, so the user terminals belonging to different antennas can be grouped into an SDMA group, and the same wireless resources are allocated to the terminals belonging to the same group. transmission.
[0050] As an embodiment of the present invention, the same wireless resource includes infinite resources such as the same time slot, code channel and frequency resource.
[0051] More specifically, the base station allocates the same radio resources for data transmission to terminals belonging to the same SDMA group, including:
[0052] The downlink data is sent based on the antenna to which the terminal belongs, and the terminal uses the same radio resources to transmit data. At the same time, the base station receives the uplink data sent by the corresponding terminal on the antenna to which the terminal belongs.
[0053] For example, when user terminal 1 belongs to antenna 1 and user terminal 2 belongs to antenna 2, the base station sends the signal to be sent by user terminal 1 only on antenna 1, and the base station sends the signal to be sent by user terminal 2 on antenna 2 only.
[0054] When a user terminal belongs to multiple antennas, joint detection of user information can be performed at this time. That is, the base station detects the uplink data sent by the terminal on the antenna to which the terminal belongs, and receives the uplink data sent by the terminal by jointly detecting all the antennas to which the terminal belongs.
[0055] When the user terminal sends data to the base station through the high-speed shared indication channel HS-SICH or the uplink enhanced physical channel E-PUCH, the base station will carry the uplink data. Joint detection is performed after the estimated value. For example, without loss of generality, assuming that there are two users performing space division, user terminal 1 belongs to antennas 1 and 2 according to the preceding judgment, and user terminal 2 belongs to antennas 3 and 4. Then, in order to receive the data sent by user terminal 1 on the HS-SICH or E-PUCH, the base station will perform channel estimation on the data roots of the HS-SICH or E-PUCII received by antennas 1 and 2, and perform multi-antenna detection according to the joint detection method. The joint detection obtains the information data sent by the user terminal 1 . Similarly, the data of user 2 can be obtained according to the existing joint detection method for the data received by the antennas 3 and 4 .
[0056] After a complete processing process is performed on the above steps S101 to S103, a transmission and reception process is also completed between the base station and multiple terminals. With the change of time, the location of the wireless channel or the terminal will also change. Therefore, in the subsequent data transmission process, by repeating steps S101 to S103, SDMA data transmission can be continued to the user terminal.
[0057] The above method proposed by the present invention can make full use of the characteristics of the indoor distributed system. According to the large isolation between floors, the coverage area of each channel is relatively independent, and the interference between different floors is very small. Realize SDMA to users and effectively increase system capacity.
[0058] The invention also proposes a base station for realizing the space division multiple access of the indoor distributed system. like figure 2 As shown, this is a schematic structural diagram of a space division multiple access base station for realizing an indoor distributed system. The base station 200 includes: a receiving module 210 , a judging module 220 and a sending module 230 .
[0059] The receiving module 210 is used for receiving the uplink signal sent by the terminal, and performing channel estimation according to the uplink signal; the determining module 220 determines the antenna belonging of the terminal according to the result of the channel estimation, and divides the terminals belonging to different antennas into the same empty space. Division Multiple Access SDMA group; the sending module 230 is configured to use the same radio resources to send data to terminals in the same SDMA group. The same wireless resources include the same infinite resources such as time slots, code channels and frequency resources.
[0060] As an embodiment of the present invention, the receiving module 210 is configured to receive a signal of the DPCH channel sent by the terminal, and perform channel estimation according to the signal of the DPCH channel.
[0061] As an embodiment of the present invention, the judgment module 220 further includes a configuration module 221. The configuration module 221 is used to obtain a threshold Γ for judging the belonging of the terminal antenna. The judgment module 220 obtains the spatial covariance matrix of the terminal according to the multi-antenna channel estimation of the DPCH of the terminal. , for each terminal, the judgment module 220 obtains the corresponding shaping coefficient w of each antenna through the EBB beamforming algorithm (k，ka) , k=1...K, ka=1...Ka, where K, Ka represent the number of terminals and the number of antenna units respectively, when |w (k，ka) | 2Γ, the judgment module 220 judges that the terminal k belongs to the antenna ka, otherwise it judges that the terminal k does not belong to the antenna ka.
[0062]As an embodiment of the present invention, the sending module 230 sends the downlink data on the antenna to which the terminal belongs as determined by the determining module 220, and notifies the terminal to use the same wireless resources for data transmission, and the receiving module 210 determines in the determining module 220 The uplink data sent by the terminal is received on the antenna to which the terminal belongs.
[0063] As an embodiment of the present invention, the receiving module 210 further includes a joint detection module 211, in which the joint detection module 211 performs channel estimation on the high-speed shared indication channel HS-SICH or the uplink enhanced physical channel E-PUCH carrying uplink data, and in the terminal to which the terminal belongs The uplink data sent by the terminal is detected on the antenna, joint detection is performed on all antennas to which the terminal belongs, and the uplink data sent by the terminal is received.
[0064] The above equipment proposed by the present invention can make full use of the characteristics of the indoor distributed system. According to the large isolation between floors, the coverage area of each channel is relatively independent, and the interference between different floors is small. Realize SDMA to users and effectively increase system capacity.
[0065] The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.
