WO2007045185A1

WO2007045185A1 - A channel realizing method for multi-carrier system cell

Info

Publication number: WO2007045185A1
Application number: PCT/CN2006/002802
Authority: WO
Inventors: Xuezhi Yang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2005-10-20
Filing date: 2006-10-20
Publication date: 2007-04-26
Also published as: CN1953364B; CN1953364A

Abstract

A channel realizing method for multi-carrier system cell, which retains the frequency multiplex factor to be 1 within the cell, and sets schedule indication channels for main carrier and subcarrier while reducing the interference between the cells at the edge of the cell by carrier grouping layout, wherein the schedule indication channel occupying the main carrier schedules the main carrier and the schedule indication channel schedules the subcarrier, therefore the time-frequency resource needed by each schedule indication channel is reduced due to the schedule indication channels set for the main carrier and the subcarrier, respectively, which greatly reduces main carrier resource allocated to the schedule indication channel, compared with the prior art. After setting different schedule indication channels for the main carrier and the subcarrier, respectively, the mobile terminal can monitor the schedule indication channels occupying corresponding carriers on the basis of current carriers occupied by itself, therefore the load for the mobile terminal receiving the schedule indication information is reduced, compared with prior art.

Description

Channel implementation method in multi-carrier system cell

The present invention relates to multi-carrier technology, and more particularly to a channel implementation method in a multi-carrier system cell. Background of the invention

Mobile communication technology needs to support a wide range of service types such as voice, data, audio, video, and image. In order to support multiple service types, mobile communication systems are required to support higher data rates, higher spectrum efficiency, and better quality of service (QoS). , Quality of Service) provides better mobility support and wireless network coverage, enabling users to provide communication services anytime, anywhere. At present, some mobile communication uses Time Division Multiple Access (TDMA) and narrowband code division multiple access (CDMA) as the main access technologies, such as Global System for Mobile (GSM, Global System for Mobile). Communication system and CDMA IS-95 mobile communication system, some mobile communication is based on Wideband CDMA (WCDMA), such as WCDMA mobile communication system. In CDMA technology, one user's data symbols will occupy all carrier frequency widths, and different user or user data will be distinguished by spreading codes. Since the multipath channel destroys the orthogonality between the spreading codes, the CDMA technology becomes a self-interference system, and therefore, the system capacity and the frequency efficiency cannot meet the requirements of the broadband wireless communication.

Multi-carrier technology has gradually become a hotspot technology for broadband wireless communication. The basic idea is to divide a wideband carrier into multiple subcarriers and simultaneously transmit data on multiple subcarriers. In most system applications, the bandwidth of subcarriers is smaller than that of the channel. Coherent bandwidth, so the frequency is selected On the selective channel, the fading on each subcarrier is flat fading, which reduces inter-symbol interference and does not require complex channel equalization, and is suitable for high-speed data transmission. Multi-carrier technology can take many forms, such as Orthogonal Frequency Division Multiplexing (OFDM), Multicarrier-Code Division Multiple Access (MC-CDMA), Multi-Carrier Direct Extension CDMA (MC-DS- CDMA (Multicarrier-Direct Sequence-Code Division Multiple Access), Multi-tone-Code Division Multiple Access (MT-CDMA), Multi-carrier-Time Division Multiple Access (MC-TDMA), Time-Frequency Domain Two-Dimensional Expansion, and a variety of extension technologies based on the above.

OFDM technology is a relatively representative technique in multi-carrier technology, which divides a given channel into a number of orthogonal sub-channels in the frequency domain, and allows sub-carrier spectrum to partially overlap, as long as the sub-carriers are orthogonal to each other. The data signal can be separated from the aliased subcarriers.

Since the frequency reuse factor is 1, in a CDMA system with limited interference, not only the spectrum efficiency is high, but also frequency planning is not required, which simplifies network planning. However, in a multi-carrier system, the frequency reuse factor of 1 does not achieve optimal spectral efficiency. Therefore, in a frequency soft multiplexing scheme, the entire frequency band of the system is divided into two segments, one of which is used as a frequency band. The primary carrier and the other frequency band serve as subcarriers. The user at the edge of the cell can use the primary carrier, and the user at the center of the cell can use the primary carrier and the secondary carrier at the same time. Since the primary carrier and the secondary carrier are different in each cell, the edge users in different cells may use different The primary carrier can reduce or avoid co-channel interference and improve the communication quality of the cell boundary. The frequency reuse factor is still reserved within the cell, and the interference between cells is reduced by carrier group planning at the cell boundary, and the communication quality and spectrum efficiency of the cell boundary are improved.

Since the downlink channel is multiplexed by multiple users according to certain rules, and this multiplexing is changed with time. The base station needs to pass this multiplexing rule through a dedicated channel. Knowing to each mobile terminal, the mobile terminal can extract only information related to itself for demodulation, and this dedicated channel can be referred to as a scheduling indication channel. The scheduling indication channel is shared by multiple users. Therefore, a certain resource needs to be specified in advance for the scheduling indication channel. For example, in the multi-carrier system, the scheduling indication channel can occupy different subcarriers at different symbol moments, so that the scheduling can be achieved. Good frequency diversity gain.

In the technical solution of frequency soft multiplexing, the mobile terminal located at the cell edge and inside the cell needs to use the scheduling indicator channel. Therefore, the scheduling indicator channel needs to be placed on the relatively rare primary carrier to occupy the primary carrier, that is, scheduling. The indication channel occupies the primary carrier occupied by the mobile terminal located at the edge of the cell. However, since the mobile terminal located at the edge of the cell and the mobile terminal located inside the cell occupy different carriers, the mobile terminal located at the edge of the cell does not care about the scheduling indication information of the mobile terminal located inside the cell. However, since there is only one scheduling indicator channel occupying the primary carrier, the mobile terminal located at the cell edge of the primary carrier also needs to simultaneously demodulate the scheduling indication information of the mobile terminal located inside the cell, so that the occupation of the primary carrier is very high, and the cell is located in the cell. The load of the edge mobile terminal receiving the scheduling indication information is also very high. Summary of the invention

The present invention provides a channel implementation method in a multi-carrier system cell to reduce the occupation of the primary carrier by the scheduling indicator channel.

The method for implementing a channel in a multi-carrier system cell provided by the present invention includes the following steps: setting a primary carrier and a secondary carrier;

A scheduling indication channel is respectively set on the primary carrier and the secondary carrier, and a scheduling indication channel occupying the primary carrier is used for scheduling the primary carrier, and a scheduling indication channel occupying the secondary carrier is used for scheduling the secondary carrier.

After the scheduling indication channel is separately set on the primary carrier and the secondary carrier, the method further includes: The mobile terminal monitors the scheduling indication channel occupying the corresponding carrier according to the carrier currently occupied by the mobile terminal.

The step of the mobile terminal to listen to the scheduling indication channel occupying the corresponding carrier according to the carrier currently occupied by the mobile terminal is: the mobile terminal monitors the scheduling indication channel occupying the primary carrier according to the primary carrier currently occupied by the mobile terminal.

The step of the mobile terminal locating the scheduling indicator channel occupying the corresponding carrier by the carrier currently occupied by the mobile terminal is: the mobile terminal monitors the scheduling indicator channel occupying the subcarrier according to the subcarrier currently occupied by the mobile terminal.

The step of the mobile terminal listening to the scheduling indicator channel occupying the corresponding carrier according to the carrier currently occupied by the mobile terminal is: the mobile terminal, according to the primary carrier and the secondary carrier currently occupied by the mobile terminal, the scheduling indicator channel occupying the primary carrier and the occupied subcarrier The scheduling indication channel is simultaneously monitored.

Before the step of the mobile terminal monitoring the scheduling indication channel occupying the corresponding carrier according to the carrier currently occupied by the mobile terminal, the method further includes: the base station notifying the mobile terminal that the mobile terminal currently occupies.

The scheduling indicator channel occupying the primary carrier occupies different subcarriers on each time symbol within one transmission time interval.

The scheduling indicator channel occupying the subcarriers occupies different subcarriers on each time symbol within one transmission time interval.

According to the method proposed by the present invention, the frequency reuse factor is reserved within the cell, and when the cell boundary is reduced by the carrier group planning, the scheduling indicator channel is set on the primary carrier and the secondary carrier, respectively. The scheduling indicator channel of the carrier is used for scheduling the primary carrier, and the scheduling indication channel occupying the secondary carrier is used for scheduling the subcarrier. Since different scheduling indication channels are respectively set for the primary carrier and the secondary carrier, the required required for each scheduling indication channel is reduced. Time-frequency resources, greatly reducing the main carrier resources allocated to the scheduling indicator channel compared to the prior art Less. After the different scheduling indicator channels are set for the primary carrier and the secondary carrier, the mobile terminal can monitor the scheduling indicator channel that occupies the corresponding carrier according to the carrier that is currently occupied by the mobile terminal, which reduces the receiving of the scheduling indication information by the mobile terminal compared with the prior art. load. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of an existing scheduling indicator channel occupying subcarriers on a time symbol. Fig. 2 is a diagram showing the subcarriers occupied by the scheduling indication channel on the time symbol in the present invention. Mode for carrying out the invention

The invention is further described in detail below with reference to the accompanying drawings.

In a multi-carrier system, the scheduling indicator channel can occupy different sub-carriers at different symbol moments, so that a better frequency diversity gain can be obtained, as shown in FIG. 1, where the gray square is the scheduling indication channel at the corresponding time. The resources occupied by the symbols on it.

In the technical solution of the frequency soft multiplexing, the scheduling indicator channel is respectively set on the primary carrier and the secondary carrier, the scheduling indication channel occupying the primary carrier is used for scheduling the primary carrier, and the scheduling indication channel occupying the secondary carrier is used for scheduling the secondary carrier. . The entire frequency band is divided into two segments, one of which is the primary carrier and the other is the secondary carrier. The user located at the edge of the cell can use the primary carrier, and the user at the center of the cell can use the primary carrier and the secondary carrier at the same time, so that the same-frequency interference can be reduced or avoided, and the communication quality at the cell boundary can be improved.

FIG. 2 is a schematic diagram showing the sub-carriers occupied by the scheduling indication channel in the time symbol in the present invention, and only shows a situation in which the scheduling indication channel occupies subcarriers on the time symbol, and the abscissa shown in the figure is time. The symbol, the ordinate is the frequency, the entire frequency band is divided into two segments of the main carrier and the subcarrier, and each of the blocks filling the vertical line is the corresponding subcarrier occupied on the corresponding time symbol, and is respectively set on the primary carrier and the subcarrier. One scheduling indicator channel, as long as one is guaranteed The subcarriers occupied by each time symbol in each transmission time interval (TTI, Transmission Time Interval) may be different. In order to obtain a better frequency diversity gain, the scheduling indicator channel occupying the primary carrier may occupy different subcarriers in each time symbol within one TTI, and each time symbol of the scheduling indicator channel occupying the subcarrier in one TTI may be used. Different subcarriers are occupied, as shown in Figure 2. In a practical application, the scheduling indicator channel occupying the primary carrier may also occupy the same subcarrier on each time symbol in one TTI, and the scheduling indication channel occupying the secondary carrier may also occupy each time symbol in one TTI. The same subcarrier.

After the scheduling indicator channel is set on the primary carrier and the secondary carrier, the mobile terminal can monitor the scheduling indicator channel occupying the corresponding carrier according to the carrier currently occupied by the mobile terminal, that is, if the mobile terminal currently occupies the primary carrier, such as the mobile terminal edge. The terminal and the high-speed mobile terminal, the mobile terminal monitors the scheduling indicator channel occupying the primary carrier; if the mobile terminal currently occupies a secondary carrier, such as a mobile terminal located inside the cell, the mobile terminal schedules the occupied subcarrier The channel is monitored; if the mobile terminal currently occupies both the primary carrier and the secondary carrier, the mobile terminal simultaneously monitors the scheduling indicator channel occupying the primary carrier and the scheduling indication channel occupying the secondary carrier.

When the mobile terminal accesses the network or the location moves, the base station can notify the mobile terminal of the currently occupied carrier according to the location of the mobile terminal, so that the mobile terminal can monitor the corresponding indication channel according to the carrier currently occupied by the mobile terminal. For example, the base station notifies the currently occupied carrier of the mobile terminal as the primary carrier according to the location of the mobile terminal, and the mobile terminal monitors the scheduling indication channel occupying the primary carrier; for example, the base station notifies the mobile terminal of the current occupation according to the location of the mobile terminal. If the carrier is a subcarrier, the mobile terminal monitors the scheduling indicator channel occupying the subcarrier; for example, if the base station notifies the current carrier of the mobile terminal as the primary carrier and the secondary carrier according to the location of the mobile terminal, the mobile terminal pairs The scheduling indicator channel occupying the primary carrier and the scheduling indication channel occupying the secondary carrier are simultaneously monitored. In the above description of the present invention, the inner area and the boundary area of the cell may be arbitrarily divided. For example, an area centered on the base station and having a radius not greater than 50% of the radius of the cell may be divided into an inner area of the cell, and the other area of the cell The area is divided into the boundary area of the cell; an area centered on the base station and having a radius not greater than 60% of the radius of the cell may be divided into an inner area of the cell, and other areas of the cell are divided into boundary areas of the cell; The area where the base station is centered and whose radius is not more than 35% of the radius of the cell is divided into the inner area of the cell, and the other area of the cell is divided into the boundary area of the cell.

In summary, the above description is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A method for implementing a channel in a multi-carrier system cell, the main carrier and the sub-carrier are set, wherein the method further includes:

The method according to claim 1, wherein after the scheduling indication channel is separately set on the primary carrier and the secondary carrier, the method further includes:

The mobile terminal monitors the scheduling indication channel occupying the corresponding carrier according to the carrier currently occupied by the mobile terminal.

The method according to claim 2, wherein the mobile terminal monitors the scheduling indicator channel occupying the corresponding carrier according to the carrier currently occupied by the mobile terminal: the mobile terminal uses the primary carrier that is occupied by the mobile terminal. The scheduling of the primary carrier indicates that the channel is listening.

The method according to claim 2, wherein the mobile terminal monitors the scheduling indication channel occupying the corresponding carrier according to the carrier currently occupied by the mobile terminal: the mobile terminal uses the subcarrier that is occupied by the mobile terminal. The scheduling of the subcarriers indicates that the channel is listening.

The method according to claim 2, wherein the mobile terminal monitors the scheduling indication channel occupying the corresponding carrier according to the carrier currently occupied by the mobile terminal: the mobile terminal according to the primary carrier and the subcarrier occupied by the mobile terminal And simultaneously monitoring the scheduling indication channel occupying the primary carrier and the scheduling indication channel occupying the secondary carrier.

The method according to any one of claims 2 to 5, wherein before the mobile terminal monitors the scheduling indicator channel occupying the corresponding carrier according to the carrier currently occupied by the mobile station, the method further includes: the base station notifying the mobile terminal that the mobile terminal is currently occupied. Carrier.

The method according to any one of claims 1 to 5, wherein the scheduling indicator channel occupying the primary carrier occupies different subcarriers on each time symbol in a transmission time interval.

The method according to any one of claims 1 to 5, wherein the scheduling indicator channel occupying the subcarrier occupies different subcarriers on each time symbol in a transmission time interval.