TWI411317B - Radio Resource Management Architecture and Method in Base Station in Wireless Communication System - Google Patents

Abstract

The invention relates to wireless resource management framework and method inside the base station of wireless communication system. A sector frequency coordination and a distributed scheduling framework in the base station are utilized to enhance the transmission probability and information throughput of users in the sector edge. The framework and the method are specially applied to the down link of OFDMA mobile communication system and include: (1) all usable frequency band information is divided into two subbands with dividing rates &bgr;where the wireless resource of one subband is provided to the users of the sector outside the sector edge and the wireless resource from the other subband is preferentially offered to the users in the sector edge; and (2) a sector edge proprietary scheduler is independently set in the base station and dedicated to scheduling all users from the sector edge.

Description

Radio resource management architecture and method in base station in wireless communication system

The present invention relates to a radio resource management architecture and method in a base station in a wireless communication system, in particular to a radio resource management architecture for a base station in a downlink of an OFDMA mobile communication system, utilizing a frequency coordination and decentralized scheduling architecture in a base station and method.

At present, OFDMA (Orthogonal Frequency Division Multiplexing Access (OFDMA)) is regarded as a modulation and multiple access technology for the next generation of mobile communication systems (4G). In addition to Mobile WiMAX, 3GPP (The 3rd Generation Partnership) is still under development. Under the LTE (Long Term Evolution) standard, the OFDMA technology will also be adopted.

The existing WCDMA (Wideband Code Division Multiple Access (WCDMA) system uses processing gain and soft handover to combat inter-cell interference, although soft handover can effectively solve most of the problems. Intercellular interference, but when the number of users in the handover area increases, soft handover has the disadvantage of wasted system resources and reduced capacity.

The handover method implemented by the mobile WiMAX system is hard handover, while the fast cell selection and soft handover are classified as selective functions. The handover method considered by the 3GPP LTE system currently under development is fast cell selection. The so-called rapid cell selection means that the user can quickly select and convert the servo cells in the active set cells, which can be regarded as an optimized hard handover. The above-mentioned Pre-4G system delivery methods are based on the concept of hard handover. It can be seen that hard handover will become the mainstream technology for the so-called 4G system to be used for handover. However, in the OFDMA mobile communication system to achieve hard handover, there is a problem of inter-cell interference, especially in the system deployment mode with a frequency reuse factor of 1.

Considering the chain below the OFDMA system, severe inter-sector interference will result in poor channel quality, making it difficult for sector edge users to obtain high-priority transmission order in each sector scheduler, thus affecting sector edge users. The throughput of the data.

It can be seen that there are still many shortcomings in the above-mentioned methods of use, which is not a good design, but needs to be improved.

In view of the shortcomings derived from the above-mentioned conventional methods, the inventor of the present invention has improved and innovated, and after years of painstaking research, he finally successfully developed and completed the wireless resource management device and method based on the fast sector selection technology.

[Object of the Invention]

The object of the present invention is to provide a radio resource management architecture and method in a base station in a wireless communication system, which is to improve the transmission rate of sector edge users, thereby improving the data throughput of sector edge users, and providing an effective and particularly applicable A radio resource management architecture and method in a base station of an OFDMA mobile communication system.

The radio resource management architecture and method in the base station in the wireless communication system for achieving the above object of the present invention utilizes the sector frequency coordination and distributed scheduling architecture in the base station to increase the transmission rate of the sector edge users, thereby achieving the improvement of the sector edge user. Data circulation. The method uses the sector frequency coordination method in the base station to divide all available frequency band resources into two sub-bands, the division ratio of the two sub-bands is β value, and one sub-band is used by non-sector edge users in the sector, and A sub-band is preferentially supplied to sector edge users in the base station for use. The distributed scheduling architecture is used to independently generate a sector edge exclusive scheduler, which specializes the scheduling of all sector edge users in the base station to improve the scheduling probability of the sector edge users, and the so-called scheduling probability refers to obtaining The highest priority transmission order probability.

The present invention is to improve the radio resource management architecture and method in a base station in a conventional OFDMA wireless communication system, so that the data throughput of the sector edge users can be improved. Since the sectors causing inter-cell interference are controlled by the same base station and do not involve cross-base station resource control, the coordination of the sector resources in the base station and the appropriate scheduling architecture can be pre-transmitted by increasing the sector edge. The user's scheduling probability to increase the data throughput of the sector edge users.

Intercellular interference can be divided into two cases: Inter-base station inter-cell interference: means that inter-cell interference is caused by cells under the control of multiple (or different) base stations; Intra-base station Inter-cell interference: Also known as inter-sector interference, means that inter-cell interference is caused by sectors under the control of the same base station.

A base station can control multiple sectors, but the most common configuration is that one base station contains three sectors. Without loss of generality, assuming that a base station has three sectors, as shown in Figure 1, user k is at the edge of the sector, and if user k's data is transmitted in sector 1, then sector 2 is utilized. The same channel serving other users (such as the general user M) will cause interference to the sector edge user k.

Referring to FIG. 2, FIG. 2 is a schematic diagram of a scheduler implemented in a base station, and includes schedulers 11, 12, and 13 located in sector 1, sector 2, and sector 3. Each sector scheduler assigns radio resources to different users based on the data priority message. The information used in the scheduler to determine the transmission priority includes information such as channel quality, upper buffer status, and service priority indicators.

The present invention utilizes this concept, and utilizes a frequency coordination mechanism and a distributed scheduling architecture in a base station to provide an effective radio resource management architecture and method for an intra-base station of an OFDMA system.

In an OFDMA system, if its radio resource is in a sub-frame in the time domain, and the frequency domain is a resource block in units of m sub-carriers, then in terms of a sub-code frame, The time-frequency 2D resource configuration will only have the frequency domain left. That is to say, the scheduler of the OFDMA system will perform frequency domain resource block configuration in units of one subcode frame.

Consider a downlink transmission of an OFDMA system with a frequency coverage factor of 1. Referring to FIG. 3, it is a diagram of a sector frequency coordination mechanism in a base station of a radio resource management architecture and method in a base station in the wireless communication system of the present invention. Suppose a base station has three sectors, and the number of available subcarriers per sector is N _u , where P _B subcarriers are reserved for sector edge users, and the remaining (N _{u -} P _B ) times The carrier is used by the general user in the sector (ie, the non-sector edge user), that is, the shared ( β × 100)% of the spectrum resources are preferentially configured for the sector edge users, where β = P _B / N _u , and the remaining The 1-( β × 100)% of the spectrum resources are allocated for use by non-sector edge users. The P _B subcarriers form a frequency band B 20 (ie, a hatched portion), and (N _{u -} P _B ) subcarriers form a frequency band A 30, and all resource blocks located in the frequency band B 20 are preferentially supplied to the sector edge user for use, if When a resource block located in Band B 20 is not used by a sector edge user, it will be included in Band A 30 to provide general user use in the sector. Since the sector edge user has priority usage rights in the frequency band B 20, the transmission rate (or scheduling probability) of the sector edge users can be increased, and the transmission rate refers to the probability of obtaining the highest priority transmission order in the scheduler.

Without losing the generality, a base station has three sectors. Referring to FIG. 4, it is a schematic diagram of a distributed scheduling in a base station of a radio resource management architecture and method in a base station in a wireless communication system according to the present invention. This architecture is divided into two parts: Band A Scheduler 40 and Band B Scheduler 50.

Band A Scheduler 40: Band A Scheduler 40 contains schedulers 41, 42 and 43 located in Sector 1, Sector 2 and Sector 3, which are dedicated to the scheduling of Band A 30 resource blocks. Since the resource blocks located in band A 30 are only used by non-sector edge users, for a resource block located in band A 30, the schedulers 41, 42 and 43 of sector 1, sector 2 and sector 3 will Scheduling only for general users (ie, all non-sector edge users) in each sector.

Band B Scheduler 50: The Band B Scheduler 50 is composed of a sector edge exclusive scheduler 51, which does not belong to Sector 1, Sector 2 or Sector 3, and is dedicated to the Band B 20 resource block. schedule. Since the sector edge users in the base station are controlled by the same base station, a sector-specific exclusive scheduler 51 can be additionally provided, which is dedicated to the scheduling of all sector edge users. That is to say, all the sector edge users under the control of the base station are scheduled by the sector edge exclusive scheduler 51 to determine the transmission priority order.

All resource blocks located in Band B 20 will be preferentially served to the sector edge user, but when a resource block located in Band B 20 is not used by the Sector Edge user, it will notify Band A Scheduler 40 via control message S1. This resource block is included in Band A 30 for use by the general user in the sector.

The sector edge-specific scheduler 51 is only responsible for the scheduling of sector edge users in all base stations, because the competition of non-sector edge users is reduced, so that the transmission rate of each user at the sector edge is increased. The traditional non-distributed scheduling architecture will add sector edge users to the scheduler of its corresponding servo sector (ie, scheduler 11, scheduler 12 or scheduler 13 of Figure 2), due to the scheduler. The competitors include non-sector edge users, so it is difficult for sector edge users to achieve higher transmission priority in this scheduling architecture (usually the channel quality of the sector edge users will be poor).

Since the operating environment of each base station may be different, for example, there is a highway passing through the edge of the sector or the density of the sector edge user is increased due to the problem of the location of the base station. At this time, the value of β must be increased to meet the needs of the user at the edge of the sector; If the sector edge users covered by the base station are scarce, the value of β must be lowered to increase the system performance. Therefore, the beta value setting of each base station may be different.

Furthermore, since the distribution of users in the base station may change drastically, for example, there is a large gathering at the edge of the sector, or because there are multiple high-volume users (such as video and audio users) requesting services at the edge of the sector (at a time), at this time, β The value has to be increased. Therefore, the beta value setting of a base station can be dynamically adjusted (in time) according to the user distribution status and the application service type in the base station at each time.

[Features and effects]

The radio resource management architecture and method in the base station in the wireless communication system provided by the present invention has the following advantages when compared with other conventional technologies: 1. The present invention provides a frequency band by using a sector frequency coordination mechanism in a base station. Priority is given to sector edge users to increase the transmission rate of the sector edge users, thereby increasing the data throughput of the sector edge users.

2. The present invention achieves an increase in the transmission rate of the sector edge users by separately distributing a sector edge exclusive scheduler by the distributed scheduling architecture, thereby increasing the data throughput of the sector edge users.

The detailed description of the present invention is intended to be illustrative of a preferred embodiment of the invention, and is not intended to limit the scope of the invention. The patent scope of this case.

To sum up, this case is not only innovative in terms of technical thinking, but also has many of the above-mentioned functions that are not in the traditional methods of the past. It has fully complied with the statutory invention patent requirements of novelty and progressiveness, and applied for it according to law. Approved this invention patent application, in order to invent invention, to the sense of virtue.

1. . . Sector 1

2. . . Sector 2

3. . . Sector 3

4. . . Base station

5. . . User k

6. . . User M

7. . . Channel

8. . . Other users

9. . . Control message S1

11. . . Sector 1 scheduler

12. . . Sector 2 scheduler

13. . . Sector 3 scheduler

20. . . Band B

30. . . Band A

40. . . Band A scheduler

41. . . Band A sector 1 scheduler

42. . . Band A sector 2 scheduler

43. . . Band A sector 3 scheduler

50. . . Band B scheduler

51. . . Sector edge exclusive scheduler

FIG. 1 is a schematic diagram showing inter-sector interference in a base station; FIG. 2 is a schematic diagram of a scheduler implemented in a base station; FIG. 3 is a block diagram of a base station in a radio resource management architecture and method in a radio communication system according to the present invention; Frequency coordination mechanism diagram; FIG. 4 is a diagram of a distributed scheduling architecture in a base station of a radio resource management architecture and method in a base station in the wireless communication system.

1. . . Sector 1

2. . . Sector 2

3. . . Sector 3

4. . . Base station

20. . . Band B

Claims (8)

A method for managing radio resources in a base station in a wireless communication system is to increase the transmission rate of a sector edge user by providing a frequency band to preferentially use a sector edge user by using a sector frequency coordination mechanism in the base station, thereby increasing a sector. The data flow of the edge user includes the following steps: a. dividing two sub-bands by all frequency bands, the division ratio of the two sub-bands is β value; b. supplying the radio resources to which one sub-band belongs to the sector The mid-range sector edge user uses; c. preferentially supplies the radio resource to which the other sub-band belongs to the sector edge user. The radio resource management method in the base station in the wireless communication system according to the first aspect of the invention, wherein the ratio of the two sub-bands is β , and according to different operating environments of the base stations in the system, different ratios of beta values between the base stations are used. Distribution. The radio resource management method in the base station in the wireless communication system according to the first aspect of the invention, wherein the division ratio β value of the two sub-bands is dynamically adjusted according to the user distribution status and the application service type in the base station. A radio resource management architecture in a base station in a wireless communication system is a distributed scheduling architecture for implementing a frequency coordination mechanism of a radio resource management method, which includes: a. a plurality of schedulers located in sectors of the base station, Responsible for the scheduling of non-sector edge users in each sector, the number of subcarriers used by each sector is N _u , wherein P _B subcarriers are reserved for the sector edge users, and the rest (N _u -P _B The subcarriers are used by the non-sector edge user in the sector, where β = P _B / N _u ; b. a dedicated scheduler located in the base station, responsible for scheduling of all sector edge users in the base station, The number of subcarriers used by each sector is N _u , wherein P _B subcarriers are reserved for the sector edge user, and the remaining (N _{u -} P _B ) subcarriers are used by the non-sector edge user in the sector. Where β = P _B / N _u . The intra-base station radio resource management architecture in the radio communication system according to claim 4, wherein the scheduler of each sector in the base station is responsible for scheduling of non-sector edge users in the sector, and using 1 - ( β × 100)% of the spectrum resource. The intra-base station radio resource management architecture in the radio communication system according to claim 4, wherein the dedicated scheduler in the base station is responsible for scheduling the sector edge users in the base station, and uses ( β × 100) )% of the spectrum resources. The base in the wireless communication system as described in claim 4 The in-station radio resource management architecture, wherein the dedicated scheduler in the base station releases the associated radio resource to the scheduler of each sector in the base station by the control message S1 for use by the non-sector edge user in the sector. The intra-base station radio resource management architecture in the radio communication system according to claim 7, wherein the transmission condition of the control message S1 comprises: a. no sector edge user in the base station; b. all sector edges in the base station The user has no data to transmit; c. The channel quality of all sector edge users in the base station cannot meet the minimum requirements.