KR100754935B1 - A resource management method for multiple channel wireless communication system - Google Patents

Abstract

The present invention provides a resource allocation method of a multi-channel wireless communication system for allocating resources through interworking between different resources in a multi-channel and optimizing the signal-to-interference noise ratio or channel capacity at the cell edge.

The present invention divides a resource region by dividing a frequency band of each channel in a multi-channel, but divides one cell locally, such as an inner cell and an outer cell, and allocates an arbitrary multichannel to the inner cell or region, and assigns the outer cell. Or by sharing the allocated multi-channel in the region and allocating the remaining portion, this invention can be achieved by converting the resource allocation locally in a given multi-channel frequency band and using the internal and external cells By interlocking and adjusting the resource allocation of the channel used only in the cell, the signal-to-interference noise ratio (SINR) in the cell is converted to reduce the reception error rate in the cell and maximize the cell capacity.

Wireless communication, multichannel, resource allocation, SINR, cell total capacity

Description

A RESOURCE MANAGEMENT METHOD FOR MULTIPLE CHANNEL WIRELESS COMMUNICATION SYSTEM}

1 is a diagram illustrating a typical multi-channel usage.

2 is an explanatory diagram of resource division for resource allocation in the present invention.

3 is a distribution diagram of a resource structure and a user for dividing a multi-channel resource in the present invention.

4 is a diagram illustrating interference in adjacent cells.

The present invention relates to a resource allocation method of a wireless communication system, and more particularly, to a resource allocation method of a multi-channel wireless communication system for allocating resources through interworking between different resources when allocating resources in a multi-channel.

The rapid development of digital wireless communications in the last decade has given end users the opportunity to easily access a lot of information from anywhere. Wireless communication technology is now evolving into third generation IMT2000 (WCDMA, CDMA2000) after the second generation CDMA.

Next-generation wireless communication technologies such as 3G evolution technology and wireless access technologies such as WiMax / WiBro are expected to be commercialized through standardization. In addition, the next generation wireless communication (4G) technology, which is scheduled for commercialization after 2010, will be standardized in 2007.

In the rapidly developing various types of wireless communication technologies, the usable frequency bands are saturated, and the use of multiple channels to overcome the frequency band saturation requires a method for efficiently operating various frequency resources given in one cell.

FIG. 1 illustrates the concept of multiple channels, in which two frequency division duplex (FDD) combinations and two time division duplex (TDD) frequency bands are used in multiple channels. As described above, a method called a hierarchical cell structure (HCS) having a cell structure using a different frequency in one cell has been proposed in a cellular system.

Currently, more efficient resource allocation schemes for the case of using such multiple channels are being sought.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to allocate resources through interworking between different resources in a multi-channel and to optimize a signal-to-interference noise ratio or cell capacity at the cell edge when allocating resources. A resource allocation method of a wireless communication system is provided.

The resource allocation method of the multi-channel wireless communication system according to the present invention for achieving the object of the present invention, in the downlink resource allocation method in a wireless communication system using a multi-channel, each of the predetermined number of multi-channel Divide the resource region by dividing a frequency band of a channel, and divide one cell locally, such as an inner cell and an outer cell, and allocate an arbitrary multichannel to the inner cell or region, and assign the multiple to the outer cell or region. It shares the channel and allocates the rest.

The SINR can be adjusted by changing the radius of the inner cell and changing the resource allocation ratio in the multi-channel, thereby reducing the outage or gaining cell capacity.

In the resource allocation method of the multi-channel wireless communication system of the present invention for achieving the above object, in the resource allocation method in a wireless communication system using a multi-channel, the frequency band of each channel is allocated to different resources, In the band, the user in a cell in the same region is allocated with resources in cooperation with each other.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following examples are merely to illustrate the present invention is not limited to the contents of the present invention.

2 is a road illustrating a method of using resources using multiple channels according to the present invention. In the present invention, a method of using one downlink channel and another downlink one channel in order to use the minimum multi-bandwidth is shown. Considered. This can be extended to a larger number of multi-channels, and the present invention considers a method for improving downlink performance of uplink / downlink, and the present invention is directed to a transmitter (base station) of a conventional OFDM wireless communication system. Can be implemented.

If more than one channel can be used by the BS, it is preferable to allocate resources by interworking two channels in order to increase trunk efficiency between each channel.

Thus, if resources are efficiently divided and operated according to regions in uplink communication, gains in terms of Outage Probability, etc. can be obtained by adjusting the Signal to Interference and Noise Ratio (SINR), which is the same resource, with the same resources. have.

As shown in FIG. 2, by dividing one channel CH 1 in two downlink channels into three channel regions such as the p portion of the CH 1 channel, the q portion of the CH 2 channel, and the 1-q portion of the CH 2 channel. Use separately.

As shown in FIG. 3, another cell is formed in one cell so that resources are allocated to an inner cell (p 1 of CH 1 downlink (hereinafter, referred to as CH A) in CH 1 downlink). Allocate a portion of the downlink q (the ratio of allocating resources to an inner cell in CH 2: hereinafter referred to as CH B), and allocate the remaining portion of the CH 2 downlink to an outer cell (hereinafter referred to as CH C). Is assigned).

Therefore, one cell becomes an HCS (Hieratical Cell Structure) structure having two cells at the same time. The BS divides the cells into concentric circles to aid conceptual understanding without using sectored cell structures. This method can be extended to a sectored cell structure.

The CH 1 band can also be partitioned for more adaptive resource allocation to a given channel.

The Gaussian shape in FIG. 3 indicates that the distribution of users is a large number of users near the BS, and the farther away from the BS, the more the number of users is in the hot spot. The distribution for this is also as shown in FIG. 3.

In the present invention, if the resource allocation is allocated to the user a small unit of a constant OFDM subcarrier and all users require a uniform amount, as shown in FIG. The amount of resource allocation of p (CH A) of CH 1, q (CH B) of CH 2, CH 2 1-q (CH C), and also once By adjusting p and q in r, the overall cell SINR can be adjusted, thereby gaining benefits in terms of outage and cell capacity growth.

The multi-channel resource allocation method of the present invention can be optimized separately using the following two methods according to the intended use.

First, since the SINR is high at the edge of the inner cell and the outer cell from the user's point of view, the reception error (outage) is less likely to occur.

If this is expressed as an equation, it is the same as Equation (1). Here, r, p, and q may be selected to optimize SINR.

0≤p≤1, 0≤q≤1, 0≤p + q≤1,

Here, 1 is a value normalized to the number of subcarriers available in CH 1 and CH 2, respectively.

As shown in FIG. 4, SINR may be expressed as a ratio of the sum of the power transmitted from its BS1 to the interference signal transmitted from another BSk (k ≠ 1) as follows.

Here, the amount of interference varies according to path loss and shadowing according to the transmission power and distance of another BS, and the power of the signal is the reception power of the signal transmitted from the BS.

Second, the sum capacity in the cell is designed to be the maximum.

This can be expressed as:

p _opt2 , q _opt2 , r _opt2 = argmax C _total (p, q, r) (3)

0≤p≤1, 0≤q≤1, 0≤p + q≤1,

C _total = C _{CH A} + C _{CH B} + C _{CH C} (4)

C _{CH A} is the cell capacity of _{CH A} in FIG. 3, C _{CH B} and C _{CH C} are the cell capacity of _{CH B} and _{CH C} in FIG. 3, and the sum capacity of the cells is the sum of their respective cell capacities. .

To satisfy this, p, which is a ratio of resource allocation in CH 1 of the multi-channel shown in FIG. 2, q, which is a ratio of resource allocation to internal cells in CH 2, and a radius r of the inner cell are changed to have an optimal value.

The above values can be adjusted to optimize the radius r of the inner cell as described above, q, the ratio of resource allocation to the inner cell at CH 2, and p, the resource allocation ratio at CH 1, and q <loading _outer ≤1-q 1-q of CH 2 determined by.

Looking at the experimental example of the present invention as described above are as follows.

First, the user's distribution was modeled as a Gaussian distribution for the experiment. Where the cell is close to the BS, there are a lot of users like hot spots, and the number of users decreases out of the city.

The parameter value used in 802.22 is used to measure the change in SINR according to the change in resource allocation of the two channels shown above. The power used by the BS is 200W, and the BS antenna has a height of 20m and an outer cell radius of 33km.

It is assumed that there is no mutual interference between the two channels. In the present invention, the gain of the transmit / receive antenna is not considered.

The amount of interference by BS of the second tier is very small because the cell radius is 33km, so the SINR of the inner cell radius r and 33km cell edge was measured using the amount of interference in the first tier.

The modulation scheme used is OFDMA, and the OFDMA scheme assumes an OFDMA frequency hopping system with a frequency reuse ratio of 1 because of the interference average effect. The total amount of multi-channels was set to 200% (TDD: 100%, FDD: 100%), and the total amount required in the cell was set to 80%.

In addition, in order to analyze the effect of SINR, only the radio wave attenuation is considered in the interference signal transmitted from the neighbor BS. 1225, "Guidelines for Evaluation of Radio Transmission Technologies for IMT-2000," ITU, 1997).

PL (r) = 40 × (1-4 × 10 ^-3 Δh _b ) × log ₁₀ (r)-18 × log ₁₀ (Δh _b ) + 21 × log ₁₀ (f _c ) + 80 (5)

Here, D is the distance (Km) between the user and the BS, Δh _b is the height (m) of the base station, f is the carrier frequency (MHz).

From this, the change in SINR was measured while changing the amount of two resource allocations at 5Km, 10Km, 20Km, and 33Km of the inner cell. And this is shown in following [Table 1]-[Table 4], respectively. The value of LF (Loading Factor, Resource Allocation Amount) shown here is a percentage which indicates the ratio of the number of subcarriers used in one frequency band.

TABLE 1

SINR change according to LF change when r = 5km (data requirement: inner cell = 10%, outer cell = 90%)

LF (%) SINR (dB) CH A CH B CH C CH A CH B CH C 5 5 70 21.72 21.93 -19.48 6 4 70 20.95 22.86 -19.51 7 3 70 20.26 24.17 -19.62 8 2 70 19.56 25.88 -19.41 9 One 70 19.07 28.93 -19.44 10 0 70 18.62 non -19.35

TABLE 2

SINR change due to LF change at r = 10km (data requirement: inner cell = 30%, outer cell = 70%)

LF (%) SINR (dB) CH A CH B CH C CH A CH B CH C 15 15 50 5.91 6.02 -19.28 20 10 50 4.65 7.74 -19.00 25 5 50 3.68 10.85 -18.56 30 0 50 2.88 non -18.26

TABLE 3

SINR change due to LF change at r = 20km (data requirement: inner cell = 70%, outer cell = 30%)

LF (%) SINR (dB) CH A CH B CH C CH A CH B CH C 35 35 30 -8.82 -8.63 -17.78 40 30 30 -9.43 -7.99 -17.28 45 25 30 -9.91 -7.24 -16.66 50 20 30 -10.41 -6.24 -15.97 55 15 30 -10.80 -5.06 -15.12 60 10 30 -11.21 -3.34 -14.31 65 5 30 -11.44 -0.18 -13.19 70 0 30 -11.82 non -11.48

TABLE 4

SINR change due to LF change when r = 33km (data requirement: inner cell = 100%, outer cell = 0%)

LF (%) SINR (dB) CH A CH B CH C CH A CH B CH C 40 40 0 -17.41 -17.16 non 50 30 0 -18.47 -15.91 non 60 20 0 -19.11 -14.24 non 70 10 0 -19.92 -11.47 non 80 0 0 -20.26 non non

In the above table, in order to secure high SINR at the cell edge, which is the first method of resource allocation, the resource allocation in the CH 2 inner cell should be reduced as much as possible. In other words, it is necessary to supply data required for all internal cells in the CH 1 frequency band. In this way, the cell's outage can be reduced.

However, if the second method is designed to increase the cell capacity, the equation (3) should be used to adjust the inner cell radius r and the LF of CH A and CH B.

Maximizing the total capacity of the cells is to obtain the sum of the capacity for all users, so the SINR of the edge is increased to reduce the outage probability. This is a large value to obtain a capacity by keeping the three SINR values similar.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art various modifications of the present invention without departing from the spirit and scope of the invention described in the claims below Or it may be modified.

As described above, the resource allocation method of the multi-channel wireless communication system according to the present invention converts the SINR in the cell by locally converting the resource allocation in the given multi-channel frequency band and converting the resource allocation ratio, thereby converting the SINR in the cell. This can reduce outage probability or maximize cell capacity.

Claims (8)

In a downlink resource allocation method in a wireless communication system using multiple channels, Divide a frequency region of each channel in a predetermined number of multi-channels, and divide a resource region, divide one cell into an inner cell and an outer cell according to a distance from a base station, and assign an arbitrary multichannel to the inner cell, And allocating the remaining portion of the partial channels not allocated to the inner cell to the outer cell so as to share some channels of the plurality of channels with the inner cell. The method of claim 1, wherein the base station forming the cell divides the cell into concentric circles. The method of claim 1, wherein a signal-to-interference noise ratio (SINR) is adjusted by changing a radius of the inner cell. The method of claim 1, wherein the ratio of resource allocation to the inner cell in the channel used only in the inner cell of the multiple channels is p, the ratio of resource allocation to the inner cell in the channels used in the inner cell and the outer cell is q When the radius of the cell is r, 1 is normalized to the size of the channel available in each channel, and 0≤p≤1, 0≤q≤1, 0≤p + q≤1,

And minimizing the probability of outage of the user at the edge of the cell by selecting the optimal r, p, q for optimizing the signal-to-interference noise ratio (SINR). The method of claim 1, wherein the ratio of resource allocation to the inner cell in the channel used only in the inner cell of the multiple channels is p, the ratio of resource allocation to the inner cell in the channels used in the inner cell and the outer cell is q When the radius of the inner cell is r, 1 is normalized to the size of the available channels in each channel, and 0 ≤ p ≤ 1, 0 ≤ q ≤ 1, 0 ≤ p + q ≤ 1, p _opt2 , q _opt2 , r _opt2 = argmaxC A resource allocation method for a multi-channel wireless communication system, characterized in that it maximizes the capacity of a channel such as _total (p, q, r). A resource allocation method in a wireless communication system using multiple channels, It allocates resources by dividing the frequency bands of each channel, and allocates resources to users in cells of the same region even in different frequency bands, but divides one cell into an inner cell and an outer cell and is used in the inner cell and the outer cell. A method for allocating resources in a multi-channel wireless communication system, characterized in that allocating resources by interworking and coordinating resource allocation of a channel used only in a channel and an internal cell. delete 7. The multi-channel wireless communication system of claim 6, wherein the radius of the inner cell is varied to change the signal-to-interference noise ratio (SINR), thereby reducing the outtage or increasing the cell capacity. Resource allocation method.

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