TWI483568B - Multi-input multi-output wireless signal transmission and power control system - Google Patents

Description

Multi-input and multi-output wireless signal transmission and power control system

The invention relates to a wireless signal transmission system, in particular to a multi-input and multi-output wireless signal transmission and power control system.

In order to meet the transmission speed specification of wireless services developed by the 4th Generation Mobile Communications, two key technologies are adopted. One is Universal Frequency Reuse (UFR), which is used to improve the spectrum utilization efficiency of the system. . However, UFR has caused severe co-channel interference, with users near the edge of the cell being most affected. Therefore, another technology: Network Multiple-Input Multiple-Output (Network MIMO) is used to improve the communication quality of Cell-Edge User (CEU). In the two major 4G standards development organizations, Long-Term Evolution Advanced (LTE-A) and Worldwide Interoperability for Microwave Access (WiMAX), Network MIMO is called Coordinated Multi-Point (CoMP) and collaborative multi-input. Multi-output (Collaborative MIMO, Co-MIMO). Network MIMO hopes to coordinate multiple antenna signals by coordinating cooperation between multiple adjacent base stations, thereby solving the problem of low communication quality of long-term cell edge users under universal frequency reuse. In this way, the signal processing of the plurality of antennas on the transmitting end and the receiving end can be greatly improved without increasing the bandwidth or the total transmitting power, thereby greatly improving the spectrum efficiency of the wireless communication system, thereby improving the transmission rate and improving the communication quality. In the Network MIMO system, each CEU has a corresponding Cooperative Cell Set (CCS), and all base stations in the CCS cooperate to serve the CEU.

One such method is US Patent Publication 2012115469, which provides a method for interfering with coordinated User Equipment (UE) measurements and network access procedures. Utilizing the UE to determine restricted radio resources without receiving an explicit measurement configuration, in addition to The UE is used to indicate the UE's interference status and/or additional interference information to its servo base station to enhance interference coordination. Furthermore, UE measurement results can also be used for scheduling, RLM and mobility management to increase radio spectrum performance and improve user experience. .

In multi-input and multi-output networks, in order to reduce intercellular interference and to increase the efficiency of cell edge users by cooperative transmission between multiple cells, more and more multiplexed multi-output networks and hives have recently appeared. Research results of the Fractional Frequency Reuse (FFR). However, these results did not notice a close relationship between cell sectorization and system capacity. Please refer to "FIG. 1" as a conventional cell division method, which includes a central coverage area 1 adjacent to the center point 3, and an edge coverage area 2 far from the center point 3. Since the center coverage area 1 is closer to the center point 3, the user can have better wireless signal transmission and reception quality in the center coverage area 1 and on the edge coverage area 2 farther from the center point 3, the user The received wireless signal is weak. The directional antenna 4 is located at an intermediate position of the edge line 5, and thus the range of the coverage area of each of the independent directional antennas 4 has a triangular shape, and the direction in which the directional antenna 4 is directed has the strongest transmission signal quality, and The intensity of the transmitted signal at other angles on either side of the direction will gradually decrease. Please refer to "Figure 2", as shown by the antenna intensity curve 6. If the direction of the directional antenna 4 is the reference angle (0 degree), the direction is expanded to 0-~30 degrees to the left, and expands to the right. It is 0 degrees to +30 degrees, and if the angle of the user's position is 0 degrees (the direction pointed by the directional antenna 4), a better signal can be obtained; but the angle is further along the angle of the user's position. At the same time, the signal will gradually deteriorate, which will greatly affect the speed and quality of wireless transmission. The conventional cell division method is a triangle, and the edge coverage area 2 of one of the triangles shown in FIG. 1 is observed. The height of a rectangular strip 7 shown in FIG. 2 represents a corresponding one. The size of the edge area of one angle span, in other words, the larger the deflection angle from the directional antenna 4, the larger the area occupied by the corresponding rectangular strip 7 in the edge coverage area 2 of the triangle Big. It can be seen from FIG. 2 that the rectangular strips 7 and the antenna intensity curve 6 are inversely proportional, that is, the area of the region with the larger angle with the directional antenna 4 is larger. The larger the area, the worse the received signal is, and it does not meet the needs of use.

In addition, please refer to the "Figure 3" as shown in the figure, for the conventional cell division method, Any cell edge user 8 located in the edge coverage area 2, the corresponding CCS includes two adjacent base stations for cooperative cooperation, and the two base stations each have a directional antenna 4 pointing to each other. The user located in the edge coverage area 2 can only use the two adjacent cells for signal connection and data transmission, and the selectivity is less, and the received interference intensity is large, so the impact on the transmission quality is relatively More significant.

The main purpose of the present invention is to solve the problem of low signal strength of wireless transmission in the edge coverage area, resulting in poor transmission rate and transmission quality.

To achieve the above objective, the present invention provides a multi-input and multi-output wireless signal transmission and power control system, which comprises a plurality of adjacently arranged base transmitting cells, wherein the base transmitting cells are both regular polygons and respectively comprise plural numbers. a contiguous edge, a base station located at a center point of the base transmitting cell, a directional antenna disposed at the base station, and a power adjusting unit electrically connected to the directional antennas, the directional antennas The direction of the pointing is toward the connection point of the adjacent edges, and the base transmitting cell is divided into a plurality of kite segments centered on the directional antennas, and the power adjusting unit is configured to control the power output of the directional antennas .

It can be seen from the above description that the present invention distinguishes the base transmitting cells into a plurality of kite segments by changing the pointing direction of the directional antennas, thereby making the connection points of the adjacent edges farther from the center point have better wireless signals. .

Conventional technology

1‧‧‧Center coverage area

2‧‧‧Edge coverage area

3‧‧‧ center point

4‧‧‧Directional antenna

5‧‧‧Edge

6‧‧‧Antenna intensity curve

7‧‧‧ long square bars

8‧‧‧ cell edge users

this invention

10‧‧‧Base transmitting cells

11‧‧‧Adjacent sides

12‧‧‧ center point

13‧‧‧Base Station

14‧‧‧Directional antenna

15‧‧‧ Connection point

10a‧‧‧First base transmitting cell

10b‧‧‧Second base transmitting cell

10c‧‧‧ third base transmitting cell

20‧‧‧Kite segment

21‧‧‧Center coverage area

22‧‧‧Edge coverage area

30‧‧‧Interregional frequency bands

40‧‧‧Outer regional frequency bands

41‧‧‧First external regional band

42‧‧‧Second outer regional band

43‧‧‧ Third external region band

51‧‧‧Triangular interference receiving curve

52‧‧‧Ji-shaped segment interference receiving curve

61‧‧‧Triangular central coverage curve

62‧‧‧Triangular edge coverage curve

63‧‧‧The central coverage curve of the Zheng section

64‧‧‧edge section edge coverage curve

P1‧‧‧ edge position

70‧‧‧Power adjustment unit

FIG. 1 is a schematic diagram of a cell structure of a prior art.

2 is a schematic diagram showing the relationship between the antenna strength and the center edge of the prior art.

Figure 3 is a schematic diagram showing the range of cell systems of the prior art.

4 is a schematic diagram of a block configuration of the present invention.

Fig. 5 is a schematic view showing the structure of a cell of the present invention.

Fig. 6A is a schematic diagram showing the frequency use of the cell system of the present invention.

Figure 6B is a schematic diagram showing the frequency representation of the present invention.

FIG. 7 is a schematic diagram of signal interference comparison according to the present invention.

FIG. 8 is a schematic diagram of signal capacity comparison according to the present invention.

FIG. 9 is a schematic diagram showing the cumulative distribution of probability of the present invention.

The detailed description and technical content of the present invention will now be described as follows:

Referring to FIG. 4 and FIG. 5, the present invention is a multi-input and multi-output wireless signal transmission and power control system, which comprises a base transmitting cell 10 with a plurality of adjacent settings, and the bases transmit The cells 10 are all regular polygons and respectively include a plurality of adjacent edges 11, a base station 13 located at a center point 12 of the base transmitting cell 10, a directional antenna 14 disposed at the base station 13, and a The directional antennas 14 are electrically connected to the power adjustment unit 70. The directional antennas 14 are directed toward the connection points 15 of the adjacent edges 11 and are centered on the directional antennas 14 to cause the base to transmit. The cell 10 is divided into a plurality of kite segments 20 for controlling the power output of the directional antennas 14. The kite segments 20 respectively include a central coverage area 21 adjacent to the center point 12 and an edge coverage area 22 adjacent to the adjacent edge. In this embodiment, each of the base transmission cells 10 In the form of a regular hexagon, the central coverage area 21 of the kite segments 20 surrounds the center point 12 and form a circular coverage area, which cooperates with the position of the edge coverage areas 22 to form a regular hexagonal cell. Meta shape.

Please refer to "FIG. 6A" for further avoidance of mutual signal interference and increase signal transmission and reception quality, and to enhance the wireless signal for users located in the edge regions between the respective base transmitting cells 10. Quality, the present invention further discloses the configuration of the wireless signal frequency. The base station 13 is configured to transmit an inner region frequency band 30 and at least two outer region frequency bands 40, and the inner region frequency band 30 and the at least two outer region frequency band 40 frequency ranges are not overlapped with each other, and the inner region frequency band 30 is located at the same. The user of the central coverage area 21 is used by the user of the edge coverage area 22, and the actual outer area frequency band 40 is not limited to two, but may be based on the base transmission cells. The setting and shape of the element 10 are configured accordingly. In this embodiment, a plurality of base transmitting cells 10 are connected to each other to form a honeycomb-like structure. For convenience of description, any three base transmitting cells 10 adjacent to each other are defined as a first base transmitting cell. Element 10a, a second base transmitting cell 10b, and a third base transmitting cell 10c, and each base transmitting cell 10 is used to transmit one The inner zone band 30 and the two outer zone bands 40.

Please also refer to "FIG. 6B". Since the distance of the inner region band 30 is limited, each base transmitting cell 10 can use the same inner region band 30 without affecting each other. In the outer region frequency band 40, the base station 13 of the first base transmitting cell 10a is configured to transmit a first outer region frequency band 41 and a second outer region frequency band 42, and the second base transmits the base station 13 of the cell 10b. For transmitting the second outer region band 42 and a third outer region band 43, the base station 13 of the third base transmitting cell 10c is configured to transmit the first outer region band 41 and the third outer region band 43. In the first base transmitting cell 10a, the first outer region frequency band 41 and the second outer region frequency band 42 respectively correspond to three kite segments 20, and are spaced apart from each other; In the element 10b, the second outer region frequency band 42 and the third outer region frequency band 43 each correspond to three kite segments 20 and are spaced apart from each other; in the third base transmitting cell 10c, the first outer The regional frequency band 41 and the third outer regional frequency band 43 each correspond to three kite segments 20 and are spaced apart from each other.

In addition, the first base transmitting cell 10a, the second base transmitting cell 10b, and the zigzag segment 20 adjacent to the third base transmitting cell 10c are each served by an outer band 40 having a different frequency. Edge users (CEUs) located within their own cell range. And a CEU, in addition to being served by the base transmitting cell of the selected base, is provided by another two adjacent transmitting cells, and the same outer regional frequency band is also used to cooperatively serve the CEU. . As mentioned earlier, in a Network MIMO system, each CEU has a corresponding Cooperative Cell Set (CCS), and all base stations within the CCS cooperate to serve the CEU. For example, when the user shown in FIG. 5A is located at the edge position P1 of the first base transmitting cell 10a, the user's CCS includes: base transmitting cells 10a, 10b, and 10c. The kite segment 20 of the first base transmitting cell 10a uses the first outer region band 41; meanwhile, the adjacent second base transmitting cell 10b and the adjacent third base transmitting cell 10c are also used. The same first outer zone band 41 cooperates to serve the edge users of the first base transmitting cell 10a. Since the conditions of the transmission channels of the respective base stations 13 are independent of each other, when the three base transmitting cells 10a, 10b, 10c in the CCS cooperate to serve a CEU, the CEU can obtain a higher transfer giant diversity ( Macro diversity). This higher pass-through diversity advantage can help solve the problem of low signal strength in wireless coverage in edge coverage areas. And because of the adjacent The ground transmitting cell 10a, the second base transmitting cell 10b, and the third base transmitting cell 10c respectively use the first outer region frequency band 41, the second outer region frequency band 42 and the third outer field of different frequency ranges The regional frequency band 43, so the signal transmission between the CEU users they belong to does not interfere with each other, which can effectively solve the signal interference problem caused by the frequency overlap.

In terms of power control, the unit power and the number of users of the center coverage area 21 are defined as Pc and x, respectively, and the unit power and the number of users in the edge coverage area 22 are Pe and y, respectively. Since the edge users (CEU) of each edge coverage area 22 have a corresponding CCS, the CCS includes the base station 13 to which the CEU belongs and two other adjacent base stations 13 participating in cooperatively serving the CEU; therefore, For a base transmitting cell 10, not all of the users it serves are located in its base transmitting cell 10, but may also include users of other adjacent base transmitting cells 10 located in the edge coverage area 22. Therefore, in terms of power control, the user on the edge coverage area 22 of the adjacent cell must be considered together. In the present invention, the unit for serving the user on the edge coverage area 22 of the adjacent cell is defined. The power and the number of users of this type are Pe' and z, respectively. Wherein, Pta=xPc+yPe+zPe' is defined, where zPe' is the power consumed by the user to serve other adjacent cell edge coverage areas, and K=zPe'/Pta is defined, where K is greater than one When the regional critical coefficient Kmax, the power adjustment unit 70 is controlled to reduce the total power required by the user on the edge coverage area 22 of the adjacent cells. In this embodiment, when K is greater than an outer region critical coefficient Kmax. , the reduction factor can be defined If the outer region critical coefficient Kmax is not exceeded, then ρ 1=1 is defined. Therefore, the power adjustment unit 70 controls the unit power Pe' value to be ρ 1 × Pe', thereby effectively controlling the total power required to serve the edge users of adjacent cells, and thus does not affect the center coverage area 21 and the edge. The amount of power that can be allocated by the user within the coverage area 22.

In addition, when Pta is greater than an inner region critical power Pmax, the power adjustment unit is controlled to reduce the power of Pc, Pe, Pe' in a proportional manner. In this embodiment, when Pta exceeds the critical power of the inner region, Department definition ; otherwise define ρ 2=1. Therefore, the power adjustment unit 70 controls the unit power of the new central coverage area 21, the unit power in the edge coverage area 22, and the unit power outside the edge coverage area 22 are ρ 2×Pc, ρ 2×Pe, respectively. ρ 2 × ( ρ 1 × Pe'), thereby stabilizing the output power of the base station 13.

Please refer to FIG. 7 , which is a triangular interference receiving curve 51 of the prior art and a kite-shaped interference receiving curve 52 using the present invention. Wherein, for the prior art, the deflection angle is the line between the user and the center point 3, and the angle of the directional antenna 4 is sandwiched; for the present invention, the deflection angle is the user and the center point 12 The connection between the two points is the angle of the directional antenna 14. As shown in FIG. 1 and FIG. 3, the triangular interference receiving curve 51 is a conventional technique in which the directional antenna 4 is directed to the midpoint of the edge line to form a triangular signal coverage area; another figure is shown in FIG. As shown in "6A", the present invention is a signal coverage area for forming the kite section 20. As shown in Fig. 7, it can be clearly seen from the comparison of interference reception that the interference intensity received by the kite-shaped interference receiving curve 52 is lower than the conventional triangular interference receiving curve 51, and thus is better. The anti-interference ability, it should be noted that the triangular interference receiving curve 51 and the kite-shaped interference receiving curve 52 are obtained by performing interference simulation on the range of the edge coverage area 22.

Figure 8 is a comparison of the number of people using the signal capacity. First of all, please refer to the prior art "Figure 1" and Figure "3". In the performance of the prior art, it is obvious that the triangular central coverage curve 61 located in the central coverage area 1 is significantly better than the edge coverage area. The triangular edge of the 2 covers the curve 62, because the signal is strong in the central coverage area 21, so the triangular central coverage curve 61 performs better; and the signal located in the edge coverage area 2 is farther from the center point 3, In addition, the signal interference effect of the neighboring other base transmitting cells 10 makes the signal quality and the signal strength far lower than the performance of the triangular central coverage curve 61. In the performance of the present invention, please refer to "Figure 6A" and "Figure 8" for the central coverage area. The central cover curve 63 of the kite segment of 21 is similar to the central curve 61 of the triangle. Since both are closer to the base station of the center point, the performance is not much different; but the kite located in the edge coverage area 22 The segment edge coverage curve 64 is much better than the conventional triangular edge coverage curve 62, which allows the user located in the edge coverage region 22 to select the proximity due to the design of the kite segment 20 of the present invention. The other two base transmitting cells 10 are connected to the outer frequency band 40 to provide more signal source selection. In addition, as shown in FIG. 7, the present invention utilizes a kite-shaped design and receives the same. The resulting interference intensity is lower than the conventional triangular design, so that the user located in the edge coverage area 22 performs much better than the user located in the conventional triangular edge coverage area.

Please refer to "Figure 9". In the performance of the cumulative distribution of probability, the same is true for the central coverage curve 63 of the Zheng-shaped segment is similar to the triangular central coverage curve 61; and at the same probability cumulative distribution value, the edge coverage The kite edge coverage curve 64 of the region 22 is superior to the triangle edge coverage curve 62, that is, the kite segment edge coverage curve 64 can be under the same Cumulative Distribution Function (CDF) value. A higher signal to interference plus noise ratio (SINR) is obtained.

In summary, the present invention has the following features:

1. By changing the pointing direction of the directional antennas to distinguish the base transmitting cells into a plurality of singular segments, so that the connecting points of the adjacent edges farther from the center point have better wireless signals.

2. The edge coverage area of any base transmitting cell can simultaneously receive the outer zone frequency band signals of other adjacent two base transmitting cells, and can provide more options for the user to perform signal connection and data transmission, thereby improving The quality of the signal and the strength of the signal.

Therefore, the present invention is highly progressive and conforms to the requirements of the invention patent application, and the application is filed according to law, and the praying office grants the patent as soon as possible.

The present invention has been described in detail above, but the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the scope of the invention. That is, the equivalent changes and modifications made by the scope of the present application should remain within the scope of the patent of the present invention.

10‧‧‧Base transmitting cells

11‧‧‧Adjacent sides

12‧‧‧ center point

13‧‧‧Base Station

14‧‧‧Directional antenna

15‧‧‧ Connection point

20‧‧‧Kite segment

21‧‧‧Center coverage area

22‧‧‧Edge coverage area

30‧‧‧Interregional frequency bands

40‧‧‧Outer regional frequency bands

Claims (8)

A multi-input and multi-output wireless signal transmission and power control system comprises a base transmitting cell with a plurality of adjacent settings, wherein the base transmitting cells are all regular polygons, and respectively comprise a plurality of adjacent edges, and a base is transmitted at the base a base station at one of the central points of the cell, a directional antenna disposed at the base station, and a power adjusting unit electrically connected to the directional antennas, the pointing directions of the directional antennas are directed toward the adjacent sides a connection point, and the base transmitting cell is divided into a plurality of kite segments centered on the directional antennas, wherein the power adjustment unit is configured to control power outputs of the directional antennas, and the kite segments respectively comprise There is a central coverage area adjacent to the center point and an edge coverage area adjacent to the adjacent edge, and the unit power and the number of users defining the central coverage area are respectively Pc and x, and the unit in the edge coverage area The power and the number of users are Pe and y, respectively, and the unit power and the number of users outside the edge coverage area are Pe' and z, respectively, and Pta=xPc is defined. +yPe+zPe', and K=zPe'/Pta is defined, wherein when K is greater than an outer region critical coefficient Kmax, the power adjustment unit is controlled to reduce the use power outside the edge coverage region. The multi-input and multi-output wireless signal transmission and power control system as described in claim 1, wherein the base station is configured to transmit an inner region frequency band and at least two outer regional frequency bands, the inner regional frequency band and the at least two outer regions. The frequency bands of the regional frequency bands are not mutually exclusive, and the inner regional frequency bands are used by users located in the coverage area of the center, and the at least two outer regional frequency bands are used by users of the edge coverage area. The multi-input and multi-output wireless signal transmission and power control system according to claim 1, wherein the power adjustment unit is controlled to reduce the unit power outside the edge coverage area by ρ 1×Pe′, wherein . The multi-input multi-output wireless signal transmission and power control system described in claim 1, wherein when the Pta is greater than an inner region critical power Pmax, the power adjustment unit is controlled to reduce Pc, Pe, Pe' in equal proportions. Power. For example, the multi-input and multi-output wireless signal transmission and power control system described in claim 4, wherein the power adjustment unit is controlled to reduce the unit powers of Pc, Pe, and Pe' by ρ 2×Pc, ρ , respectively. 2 × Pe, ρ 2 ( ρ 1 × Pe'), where . For example, the multi-input and multi-output wireless signal transmission and power control system described in claim 2, wherein each of the base transmitting cell lines has a regular hexagon, and any three base transmitting cells adjacent to each other are defined as a first base transmitting cell, a second base transmitting cell, and a third base transmitting cell, wherein the base station of the first base transmitting cell transmits a first outer region frequency band and a second outer regional frequency band a base station of the second base transmitting cell for transmitting the second outer regional frequency band and a third outer regional frequency band, wherein the base station of the third base transmitting cell is configured to transmit the first outer regional frequency band and the first Three external regional frequency bands. The multi-input and multi-output wireless signal transmission and power control system according to claim 4, wherein the first outer region frequency band and the second outer region frequency band are respectively corresponding to the first base transmitting cell The three kite segments are spaced apart from each other; in the second base transmitting cell, the second outer region frequency band and the third outer region frequency band respectively correspond to three kite segments, and are spaced apart from each other; In the third base transmitting cell, the first outer region frequency band and the third outer region frequency band respectively correspond to three kite segments, and are spaced apart from each other. The multi-input and multi-output wireless signal transmission and power control system according to claim 5, wherein the first base transmitting cell, the second base transmitting cell, and the third base transmitting cell are adjacent to each other The kite segment uses frequency bands in different regions of different frequencies.