KR20110134730A - Transmission device for providing voice and data service in mobile telecommunication system and method for providing service thereby - Google Patents

Abstract

PURPOSE: A transmitting device and service supplying method using the same are provided to perform data scheduling in order to maximize the data throughput of a system. CONSTITUTION: A modulating and coding unit(215) receives first and second channel state information and information bit of a voice packet and a data packet. The modulating and coding unit modulates and encodes information bit according to the first and second channel state information. The modulating and coding unit outputs encoded data. A channel state information supplying unit(217) supplies the first and second channel state information to a voice scheduling unit and a data scheduling unit.

Description

Transmission device for providing voice and data service in mobile communication system and service providing method using the transmission device {Transmission Device for Providing Voice and Data Service in Mobile Telecommunication System and Method for Providing Service Thereby}

Embodiments of the present invention relate to a transmitter for providing voice and data services in a mobile communication system such as Long Term Evolution (LTE) and a service providing method using the transmitter. More specifically, since voice traffic is sensitive to time delay, voice traffic is scheduled first to satisfy the delay constraint of the voice packet and to keep the packet loss rate due to delay boundary violation as low as possible, and then the data throughput of the system. The present invention relates to a transmission apparatus for providing voice and data services in a mobile communication system for performing data scheduling in order to maximize throughput, and a service providing method using the transmission apparatus.

The generation of mobile communication is mainly divided into 1st generation mobile communication, 2nd generation mobile communication, and 3rd generation mobile communication according to how much the transmission speed has been improved. Such generation classification is international telecommunications, an international organization in the world electric and electronic field. It is administered by the International Telecommunication Union (ITU).

Looking at the characteristics of each generation, the first generation mobile communication is called analog mobile communication, it is characterized by only voice calls. That is, the speed of first generation mobile communication is 10 kbps and data transmission is impossible, and the frequency used is 200 to 900 MHz. The term analog is used in first generation mobile communication because the frequency modulation (FM) method used for transmitting voice is analog. The analog method has a disadvantage in that the call is confused and the frequency cannot be used efficiently.

On the other hand, the second generation mobile communication uses a digital method, and in addition to voice calls, it is possible to transmit data such as text messages and emails. At this time, the second generation mobile communication technology is diversified into European-style Global System for Mobile communications (GSM) and North American-style Code Division Multiple Access (CDMA).

GSM is a mobile communication method based on Time Division Multiple Access (TDMA) and asynchronous transmission network technology, which divides each frequency channel into time, and is connected with an Integrated Services Digital Network (ISDN). It is possible to access mobile data service by connecting directly to a phone, facsimile, computer, etc. without using. At this time, the transmission frequency of the base station is 935 ~ 960 MHz, the reception frequency of the base station is 890 ~ 915 MHz, the transmission and reception frequency interval is 45 MHz, it is not compatible with the conventional analog system.

CDMA is a type of multiple access method using spread-band communication technology. Since the user transmits and receives signals while sharing time and frequency, CDMA has more than 10 times the capacity, excellent call quality and security. It is characteristic. Here, spread-band communication refers to spreading and spreading a signal over a much wider bandwidth than a bandwidth of a signal to be transmitted. CDMA is difficult to detect the presence or absence of a signal due to the low power density of the signal, and because the receiver must know exactly the code used to spread the original signal in the process of despreading the received signal. Confidentiality is ensured and external disturbance signals do not interfere with communication because they are spread in the reverse process.

Third generation mobile communication is a next generation mobile communication technology that has evolved from existing CDMA and GSM such as Wideband Code Division Multiple Access (WCDMA) and High Speed Downlink Packet Access (HSDPA). The transmission speed is fast. In particular, HSDPA is theoretically able to achieve a maximum transmission rate of 14.4 Mbps and is seven times faster than WCDMA having a transmission rate of 2 Mbps. The HSDPA network can theoretically download three to four MP3 files per second.

The fourth generation mobile communication is by definition a mobile communication having a transmission speed of 1 Gbps during stop and 100 Mbps while moving, and theoretically, 1.4 GB video can be received in about 11 seconds from a mobile communication terminal. However, the frequency to be used for 4G mobile communication has not been determined yet, and research for standardization is in progress.

WiBro (Wireless Broadband Internet) is a wireless Internet technology that enables the use of high-speed Internet while moving, also called Mobile WiMAX, and serves as a bridge between 3rd generation mobile communication and 4th generation mobile communication. The WiBro features wireless internet access at speeds of 60 to 100 km, and up to 20 Mbps faster than HSDPA. WiBro is currently evolving to "WiBro Phase II" and the transfer rate is expected to increase to 30-50 Mbps.

LTE is a standard technology and advances in the standardization of 4G mobile naesewooneun camp in Europe after the GSM and WCDMA ^{communications, 3GPP (3 rd Generation Partnership Project} ) workgroup under (work group). LTE is a next-generation technology that overcomes the technical limitations of existing 3G mobile communication systems and meets the needs of users for the next 10 years or more.It will expand coverage, improve system capacity, reduce data rates and delays, and reduce costs. All measures to improve the quality of services provided while reducing costs are considered, and the mobile internet is strong.

As such, LTE has been attracting attention as a core technology for the next generation wireless communication by most mobile communication network operators. In particular, LTE has many technologies that include link adaptation, multiple-input multiple-output, etc. Among them, the scheduler and resource allocation are considered very important mechanisms. . Scheduler and resource allocation are essential considerations in design to improve data throughput, packet delay, delay jitter, and fairness among users.

Packet scheduling is the selection or determination of which packets can be transmitted in the current frame and is an important mechanism for providing Quality of Service (QoS) to other users of the Media Access Control (MAC) layer. Thus, there is a need for a well-designed scheduler to achieve high data rates and high cell data rates, and to maintain certain fairness among users.

While the scheduler provides QoS of the MAC layer, resource allocation of the PHY layer ensures the performance of the PHY layer. In LTE system, Orthogonal Frequency Division Multiplexing (OFDM) is adopted as a downlink transmission technology. Accordingly, the resource of the PHY layer in LTE is in the form of a resource block (RB), which is composed of 12 subcarriers and has a bandwidth of 180 kHz.

Scheduler and resource allocation are the hottest research topics in wireless communication. Reflecting this, many schedulers are designed to achieve different goals. Among them, round robin and maximum carrier-to-interference ratio (C / I) scheduling algorithms are well known. Round robin scheduling is a representative algorithm for scheduling without reflecting the wireless channel state, and provides maximum fairness among users by scheduling users one by one. The maximum C / I scheduling algorithm is a representative algorithm that improves system efficiency by reflecting a radio channel state that changes with time, and allocates resources to users having the best radio channel state. In this way, the system's data rate is maximized while fairness is compromised.

In addition to round robin and maximum C / I scheduling algorithms, so-called proportional fair scheduling has also been proposed to ensure a better tradeoff between data rates, i.e., wireless channel environment and user fairness. This has been widely adopted in other systems since its adoption in CDMA IS-386 systems.

1 is a diagram illustrating a structure of an eNodeB having a scheduler for LTE downlink according to the prior art.

As shown in FIG. 1, the eNodeB 100 having a scheduler for LTE downlink according to the prior art stores the traffic classified by the packet classifier 101 and the packet classifier 101 which classify downlink traffic, respectively. A buffer unit 103 and a scheduler 105 for scheduling to transmit the traffic provided from the buffer unit 103 to a plurality of user equipment (UE) (110). Here, the scheduler 105 for LTE downlink is N (0 ≤ i <N), the number of the types of traffic supported by the eNodeB 100, M (0) ≦ j <M).

Specifically, the eNodeB 100 has logical queues for N UEs 110 and M traffic types, and downlink traffic is classified by the packet classifier 101 and loaded in the corresponding queues. The scheduler 105 determines the transmission priority of the packet for each Transmission Time Interval (TTI) of 1 ms based on the supporting scheduling policy. The eNodeB 100 performs packet transmission by allocating the packet to a physical resource block (PRB), which is a physical layer transmission unit of the LTE system, according to the determined priority.

Service requirements according to traffic types can be classified into three categories: delay, packet loss rate, and bandwidth. Interactive RT services, such as Internet telephony, teleconferencing and interactive games, require strict time requirements for effective data transfer. Services such as e-mail, file and web document transfer, and e-commerce require reliable data transfer, i.e., no data loss. Services such as RT audio / video allow some amount of data loss, but file data or financial transaction data are constrained by packet loss rates. Bandwidth-sensitive services require a certain amount of bandwidth, while flexible services such as e-mail and file transfer can use less available bandwidth. In 3GPP TS 23.203, packets are classified into nine QoS Class Identifiers (QCIs) according to delay, data rate, and packet loss. The eNodeB 100 loads packets coming from the core network (or Evolved Packet Core (EPC)) into logical queues classified according to traffic types of the user according to 9 classified QCIs.

The scheduler 105 for the LTE downlink uses a dynamic scheduling scheme that allocates radio resources at a fast cycle of 1 ms for data transmission, and uses SPS to efficiently support a Voice over Internet Protocol (VolP) service. (Semi-Persistent Scheduling) mode is provided. The channel state information periodically fed back by the UE 110 is one of important factors reflected in the scheduling decision. In one PRB, four reference symbols used by the UE 110 to report channel status to the eNodeB 100 are inserted. The UE 110 periodically uses information of a plurality of reference symbols. Report the channel quality information CQI (Chanel Quality Indicator) to the eNodeB (100).

The scheduler 105 determines the priority of the packet by reflecting the factors considered in the scheduling policy including the channel state information of the UE 110 and allocates a head-of-line (HOL) packet to the PRB according to the determined priority. . The PRB is a physical layer transmission unit of an OFDMA-based LTE system and consists of 12 subcarriers during one slot. Each slot consists of six or seven OFDM symbols, each of which includes a Cyclic Prefix (CP) to mitigate interchannel interference caused by multipath fading. The total number of downlink subcarriers, Nsc, including DC (direct current) subcarriers, Nsc is equal to 12 · N _RB + 1, where N _RB means the number of PRBs. The LTE physical layer standard defines N _RBs to be dynamically configured from 6 to 100, so that downlink transmission bandwidth is applicable from 1 MHz to 20 MHz.

However, since the conventional LTE is designed to support only data services since most of its birth, the LTE system is designed as a plain IP architecture that supports only packet switching. As a result, there is a problem that LTE is not yet able to support the typical voice traffic through the circuit switch (circuit switch) which is the main source of revenue for the operators.

In addition, most research on current scheduling in LTE systems is mainly focused on data traffic, which is that voice packets are sensitive to time delays and are discarded as soon as they cross the boundaries of any delay, and data packets are resistant to delays, but data rates The more focus is on the different traffic characteristics that make them unsuitable in the context of heterogeneous / multi traffic, such as voice and data. In other words, there are many difficulties in devising a new scheduling mechanism due to heterogeneous / multiple traffic characteristics in LTE systems.

Furthermore, scheduling characteristics in OFDM systems differ from typical techniques such as WCDMA. OFDM is a completely different transmission technology than typical CDMA, WCDMA or HSPA. OFDM systems have unique characteristics. That is, in OFDM, RBs are allocated exclusively between users. This means that once an RB is assigned to one user, then it is not allowed to be used again by other users at the same time. This feature is different from CDMA technology in which resources in code form can be shared simultaneously among users. Thus, in terms of resource allocation, the unique characteristics of OFDM lead to different interests and different designs for OFDM and CDMA systems. The main purpose for resource allocation in CDMA is to minimize interference since CDMA is a self-interference system, whereas resource allocation in OFDM does not need to take this into account. The main purpose in OFDM depends on how you can finely allocate exclusively occupied (or occupied) resources to improve efficiency. Therefore, even in view of such resource allocation, there is a problem in that a mechanism for scheduling voice and data packets simultaneously cannot be easily devised.

Embodiments of the present invention are directed to scheduling voice traffic first in order to satisfy delay constraints of voice packets and to keep packet loss rates due to delay boundary violations as low as possible, and then to perform data scheduling to maximize data throughput of the system. An object of the present invention is to provide a transmission apparatus for providing a voice and data service in a mobile communication system and a service providing method using the transmission apparatus.

An apparatus for providing voice and data services in a mobile communication system according to an embodiment of the present invention receives a voice packet for voice service users and first channel state information (CSI) for the mobile terminal of the voice service users. Analyzes the voice packet, allocates Vmax resource blocks among the N _C resource blocks preferentially for the voice packet, and checks the length of the voice packet to which the Vmax resource blocks are allocated, The resource block may include a voice scheduling unit configured to allocate the resource block according to a priority determined according to the analysis result of the first channel state information and the voice packet; The receiving a second channel state information for the mobile terminal of the data packet and the data service user for the data service users, and taking the analysis of the Vmax of the resource blocks to locate the user with the largest channel gain for the user N _C Allocating remaining resource blocks except for Vmax resource blocks among the total resource blocks for the data packet, and checking the length of the data packet to which the remaining resource blocks are allocated, the remaining resource block is the second channel state information. A data scheduling unit in which an assignment is made according to the present invention; Receive a series of information bits for the voice packet and the data packet and the first and second channel state information, and receive the series of information bits in different ways according to the first and second channel state information. A modulation and coding unit for modulating and encoding and outputting encoded data; And a channel state information providing unit for providing the first and second channel state information to the voice scheduling unit, the data scheduling unit, and the modulation and coding unit, respectively.

In addition, a service providing method of a transmitting apparatus for providing voice and data services in a mobile communication system according to an embodiment of the present invention is a voice packet for voice service users and a first channel state for the mobile terminal of the voice service users. Receives the information (CSI), analyzes the voice packet, allocates Vmax resource blocks among the N _C resource blocks preferentially for the voice packet, and determines the length of the voice packet to which the Vmax resource blocks are allocated. Checking, wherein the Vmax resource blocks are allocated according to a priority determined according to the analysis result of the first channel state information and the voice packet; The receiving a second channel state information for the mobile terminal of the data packet and the data service user for the data service users, and taking the analysis of the Vmax of the resource blocks to locate the user with the largest channel gain for the user N _C Allocating remaining resource blocks except for Vmax resource blocks among the total resource blocks for the data packet, and checking the length of the data packet to which the remaining resource blocks are allocated, the remaining resource block is the second channel state information. A data packet scheduling step of allocating data according to the allocation; And receiving a series of information bits for the voice packet and the data packet and the first and second channel state information and in a different manner according to the first and second channel state information. And modulating and encoding to generate encoded data.

According to an embodiment of the present invention, a scheduling scheme that takes into account different QoS requirements and traffic characteristics between voice and data traffic by performing scheduling to ensure higher priority for voice QoS when scheduling voice and data traffic. Will be able to provide

As a result, it is possible to provide a service to voice service users who are sensitive to service quality among voice and data service users, thereby improving service.

In addition, the embodiment of the present invention considers not only the packet length but also the resources of the PHY layer. The main contributions are:

First, by considering the characteristics of voice packets such as fixed length and sensitivity to delay, it is possible to keep the packet loss rate of VolP traffic as small as possible and maximize the data rate of the data packet.

Second, some of the schemes according to embodiments of the present invention may be well suited to most existing scheduling algorithms for LTE systems. That is, the scheme according to the embodiment of the present invention will be an improvement and complement of other scheduling algorithms.

Third, by considering the potential impact that packet length can be placed on a resource, embodiments of the present invention may reduce the packet loss rate for both voice and data packets, and may also utilize RB resources efficiently.

Fourth, according to an embodiment of the present invention, an adjustable parameter Vmax is provided to provide a compromise of the allocated resource between voice and data traffic. Operators will be able to adjust the performance for voice and data through this parameter.

1 is a diagram illustrating a structure of an eNodeB having a scheduler for LTE downlink according to the prior art;
2 is a diagram showing the structure of a transmitting device for providing a voice and data service according to an embodiment of the present invention;
3 is a diagram illustrating a structure of a voice scheduling unit of FIG. 2;
4 is a diagram illustrating a first compensator of FIG. 3;
5 is a diagram illustrating a structure of a data scheduling unit of FIG. 2;
6 is a view illustrating an operation process of the voice scheduling unit of FIG. 3;
7 is a diagram illustrating an operation process of the data scheduling unit of FIG. 5.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected or connected to that other component, but between components It will be understood that may be "connected", "coupled" or "connected".

The focus of the embodiment of the present invention is on downlink transmission. Assume that there are Nv + Nd voice and data consumers in the system. Here, the first Nv users have voice traffic, and the remaining Nd users have data traffic. Each voice packet has a severe delay boundary. In other words, the voice packet is discarded from the buffer when the delay boundary is exceeded. It is assumed that the data packet has no delay constraint. It is assumed that voice packets have the same length while data packets have different lengths of bits. As in the general case, it is assumed that each user in the system has only one active session. In addition, it is assumed that as many resource blocks (RB) as Nc in the system.

FIG. 2 is a diagram illustrating a structure of a transmitter for providing a voice and data service according to an exemplary embodiment of the present invention, FIG. 3 is a diagram illustrating a structure of a voice scheduling unit of FIG. 2, and FIG. 4 is a first diagram of FIG. 3. It is a figure which shows a compensation part. 5 is a diagram illustrating a structure of the data scheduling unit of FIG. 2.

As shown in Figures 2 to 5, the transmission apparatus for providing voice and data services in LTE according to an embodiment of the present invention, as may be provided in the eNodeB, for example, at least scheduling and resource block allocation unit 210 ). In addition, the transmitting apparatus includes a buffer unit 200, a transmission data processing unit 220, and a transmission antenna 230 .

Here, the buffer unit 200 includes a first buffer unit 201 and a second buffer unit 203. The first buffer unit 201 is composed of a plurality of buffers and temporarily stores information provided from voice service users of Nv for a specific time. The second buffer unit 203 also includes a plurality of buffers, each of which temporarily stores information provided from Nd's data service users, such as data information service providers.

The serial information of the voice packet stored in the first buffer unit 201 has a severe delay boundary. In other words, the first buffer unit 201 may maintain the information of the voice packet stored in the memory for a predetermined time, but if the delay time is exceeded, the first buffer unit 201 discards the voice packet. That is, the stored voice information is output. At this time, the voice packet information stored in the first buffer unit 201 has the same length. On the other hand, since the information of the data packet stored in the second buffer unit 203 is not very sensitive to the delay compared to the voice packet, it does not receive a special delay constraint. Each data packet also has different lengths of information bits, unlike voice packets.

For example, a plurality of users who have a receiving device such as a mobile communication terminal receive voice information provided from a transmitting device and make a call, and may react very sensitively when the call is disconnected or the call quality is degraded. On the other hand, many users who use data services tend not to react sensitively even if some delay occurs. In other words, this may mean that users do not visually perceive the delay of data packets, but most users believe that the delay is due to the performance of the transmission line or their receiving device. You may tend to take it for granted.

In view of this, how long the first buffer unit 201 in the embodiment of the present invention should store the same length voice packet information provided from a plurality of voice service users in memory in order to determine the best QoS. Becomes important.

The scheduling and resource block allocator 210 may include a voice scheduling unit 211 for scheduling a voice packet to allocate a resource block, a data scheduling unit 213 for allocating a resource block by scheduling a data packet, and information on voice and data packets. A modulation and coding unit 215 for modulating and coding bits, and for example, channel state information (CSI) of a receiving apparatus such as a mobile communication terminal to receive a voice scheduling unit 211, a data scheduling unit 213, and modulation and coding And a channel state information providing unit 217 respectively provided to the unit 215.

Herein, the scheduling and resource block allocator 210 preferentially allocates Vmax resource blocks among all N _C resource blocks that can be allocated in the system for voice packets in order to reduce a time delay occurring during voice packet transmission. _The remaining resource blocks other than the Vmax resource blocks among the _C total resource blocks are allocated for the data packet. At this time, Nc and Vmax can be freely adjusted by the designer.

The scheduling and resource block allocation unit 210 according to an embodiment of the present invention is designed to schedule both packets as long as the QoS requirements of the voice and data packets are satisfied. At this time, the following two points are carefully considered.

The first is that voice and data packets have different characteristics. In other words, VolP packets are fixed in length while data packets are variable in size. In addition, voice packets are much more sensitive to time delay, which means that once a delay boundary is exceeded, voice packets are immediately discarded. However, data packets are usually tolerant of delay. Furthermore, the QoS requirements of voice and data packets are different. That is, packet delay and delay jitter are two major QoS indices for voice traffic, while data traffic is more focused on data rate.

The second is about the potential impact of packet length. In LTE, resource blocks are used to transmit (or carry) packets. Since packets have different lengths and resource blocks are allocated exclusively among users, the number of resource blocks can be different for different packets. This further relates to the fact that the capacity, i.e., the rate for different packets, is different.

When transmitting a body, i.e., a packet, there is no doubt that the resource block assigned to a particular packet must have sufficient "capacity" to transmit the corresponding (or corresponding) packet. On the other hand, the transmission capacity of the allocated resource block must not exceed the packet length too much. Otherwise, this will certainly be a waste.

To give a clearer way, assume that resource blocks are containers. Its role is to contain a certain amount of water. Suppose a packet is a certain amount of water. Therefore, different packets will correspond to different amounts of water. Then two things become clear.

In order to successfully send packets, the volume of water must not exceed the volume of the container. That is, the length of the packet must be less than or equal to the capacity of the allocated resource block.

On the other hand, the container should be able to hold as much water as possible for efficient use. This means that the difference between the length of the packet and the capacity of the resource blocks to which the packet is allocated should be kept as small as possible.

Considering these two points, if the length of the packet exceeds the capacity of the allocated resource block, it causes a packet transmission failure, and if the length difference between the packet length and the capacity of the resource blocks to which the packet is allocated is large. It will be appreciated that the efficiency of resource blocks, i.e., the efficient resource allocation is reduced.

The voice scheduling unit 211 performs scheduling of voice packets and selects and determines which packet should be transmitted in each time slot among a large number of candidate voice packets. More specifically, the voice scheduling unit 211 receives a voice packet for voice service users and first channel state information (CSI) of a mobile communication terminal of voice service users, analyzes the received voice packet, and N _C. The Vmax resource blocks are allocated among the total resource blocks first for the voice packet, and the length of the voice packet to which the Vmax resource blocks are allocated is checked. In this case, the Vmax resource blocks are allocated according to the priority determined according to the analysis result of the first channel state information and the voice packet when allocating the resource blocks.

To this end, the voice scheduler 211 includes an initial RB allocator 300 and a first compensator 310 as shown in FIG. 3. The initial RB allocator 300 allocates the RB based on the priority of the voice packet, and the first compensator 310 considers the influence of the packet length. As a result, it satisfies the delay constraint of the voice packet and at the same time keeps the packet loss rate due to the violation of the delay boundary as low as possible.

The widely adopted voice traffic model with respect to voice traffic in the initial RB allocator 300 is specified in the ITU P. 59 Recommendation. According to the model, speech consists of two stages: talk spurt and silence. One step alternates with the other. In the unvoiced phase, no voice packet is generated. Voice packets occur in the speech stage. Furthermore, voice packets are divided into two types, a common voice packet and a voice activity detection packet. Common voice packets contain almost all of the information in speech, whereas VAD packets contain little information.

Based on the speech model described above, the speech scheduling section 211 according to the embodiment of the present invention schedules the first speech since the common speech packet includes almost all information, and is much more than the VAD packet containing almost no information. It has a high priority.

The initial RB allocator 300 allocates a resource block (RB) for voice packets from voice service users provided by the first buffer unit 201. In this case, the resource block means to allocate a block of a size that is occupied in a specific time interval in one channel to transmit the packet as a unit, different packets may have different lengths. Therefore, resource blocks are allocated exclusively among users, the number of resource blocks may vary according to packets, and the capacity, that is, the transmission rates for packets, may vary. The initial RB allocator 300 according to an embodiment of the present invention analyzes a voice packet when allocating a resource block and allocates the resource block based on the priority.

For example, when each voice packet provided from the first buffer unit 201 is called i, and the resource block at that time is j, the initial RB allocator 300 gives priority P _ij , which is < It can be expressed as Equation 1>.

Where r _ij Is the data rate of user i for resource block j.

The brief description of each parameter in Equation 1 is as follows.

P _type is the priority of the voice packet. P _type = β indicates a common voice packet, and P _type = 1 indicates a VAD packet.

V _i (t) represents the number of packets dropped at the maximum time t due to the user's delay boundary violation.

W _i represents the time when the HOL (Head-of-Line) packet of the i-th user expires. The smaller W _i , the more urgent it is to send a packet.

Based on Equation 1, a process of assigning the initial RB allocation based on the priority in the initial RB allocation unit 300 will be described as follows.

의 식에 따라 내림차순으로 정렬한다. 여기서, h_ij는 리소스블록 j에 대한 이용자 i의 채널 이득을 나타낸다.Step 1: For each resource block j

Sort in descending order according to the equation. Where h _ij represents the channel gain of user i for resource block j.

Step 2: Select the V _max resource blocks. The set is represented by S _v . Where S _v is a set for speech traffic.

The parameter V _max indicates the maximum number of resource blocks that can be allocated to voice traffic. This parameter provides a compromise between voice and data users. At least Nc-V _max resource blocks are left for data traffic.

을 갖는 이용자를 선택한다. 그런 다음 i번째 음성 사용자에게 j 번째 RB를 할당한다.Step 3: If RB _j ∈ S _v , then the highest priority

Select a user who has Then assign the j th RB to the i th voice user.

In addition, the first compensator 310 compensates for the impact that the voice packet length has on the scheduling. As part of solving the problem, as illustrated in FIG. 4, the first compensation unit 310 may include a packet inspecting unit 400, a packet acknowledging unit 410, a resource releasing unit 420, a resource reassigning unit 430, and the like. The surplus resource release unit 440 and the surplus resource reallocation unit 450 are included.

The packet inspecting unit 400 checks whether the capacity of the resource allocated to the voice packet by the initial RB allocating unit 300 is greater than or equal to the length of the packet. That is, the packet inspecting unit 400 selects at least one of the received packets and checks whether the capacity of the resource allocated to the selected packet or the capacity of the resource block is greater than or equal to the length of the selected packet. In this case, the packet inspecting unit 400 may set an index to 1 for packets to which an arbitrary resource is allocated.

The packet acknowledgment unit 410 determines that the current packet is selected for the selected packet when the capacity of the resource allocated to the selected packet is greater than or equal to the length of the selected packet and the difference between the capacity of the resource allocated to the selected packet and the length of the selected packet is within a predetermined value. Approve the resource allocation result of. When the current resource allocation result for the selected packet is approved, the packet inspecting unit 400 preferably increases the index by one.

At this time, if the number of increased indexes is less than or equal to the number of candidate packets remaining to be transmitted, the packet inspecting unit 400 selects at least one of the candidate packets and checks whether the capacity of the resource allocated to the selected candidate packet is greater than or equal to the length of the selected candidate packet. It is preferable to check again.

If the length of the selected packet exceeds the capacity of the resource allocated to the selected packet, the resource release unit 420 releases the resource or resource block allocated to the selected packet provided by the packet inspecting unit 400.

At this time, the resource reassignment unit 430 reallocates the resources released by the resource release unit 420 among other packets, and provides the packets to the packet inspection unit 400.

In addition, when the difference between the capacity of the resource allocated to the selected packet and the length of the selected packet is greater than a predetermined value, the surplus resource release unit 440 releases the surplus resource among the resources allocated to the selected packet.

At this time, the surplus resource reassignment unit 450 reallocates among other candidate packets remaining to transmit the resources released by the surplus resource release unit 440. The packets are then provided to the packet acknowledgment unit 410.

Here, the reallocation may cause a change in the priority of scheduling among the remaining packets, and the surplus resource may be a resource in the latter half exceeding the length of the selected packet, and the first half by the length exceeding the length of the selected packet. It may be a resource of. However, the portion of the surplus resources for releasing is not limited to those described, and various portions may be selected as surplus resources according to the designer's selection.

On the other hand, after preferential scheduling of voice traffic, at least Nc-V _max resource blocks are left for data traffic. In this case, let S _{D be} a set of the remaining resource blocks. Since data packets have no delay constraints, data scheduling aims to maximize the data rate of the entire system. To this end, the data scheduling unit 213 according to the embodiment of the present invention applies a greedy approach. Here, the greedy approach means processing from the smallest processing time, that is, from the smallest completion time. Already given processing time of all processes, sort by processing time and process them sequentially.

As illustrated in FIG. 5, the data scheduling unit 213 receives data packets for data service users and second channel state information for mobile communication terminals of data service users, and analyzes Vmax resource blocks to maximize the maximum channel number. The user having a gain is found and the remaining resource blocks except for Vmax resource blocks among the N _C total resource blocks are allocated for the data packet, and the length of the data packet to which the remaining resource blocks are allocated is checked. At this time, the remaining resource blocks are allocated according to the second channel state information.

To this end, the data scheduling unit 213 analyzes the RBs of the voice packets provided by the voice scheduling unit 211 and performs RB analysis and RB reassignment for reallocating the RBs for the data packets provided by the second buffer unit 203. Part 500 and a second compensator 510 to compensate for the impact the packet length on the scheduling. Here, when the RB analysis and RB reassignment unit 500 satisfies each RB _j ∈ S _D , the RB analysis and the RB reassignment unit 500 find the user i having the maximum channel gain, and then allocate the j th resource block to the i th user.

In addition, the second compensation unit 510 performs a compensation step on the packets provided by the RB analysis and RB reassignment unit 500. The second compensator 510 is not significantly different from the structure of the first compensator 310 illustrated in FIG. 4. Therefore, the second compensator 510 is replaced with the contents of the first compensator 310 described with reference to FIG. 4, and further description thereof will be omitted.

Referring back to FIG. 2, the modulation and coding unit 215 receives a series of information bits for the voice and data packets from the data scheduling unit 213 and transfers the received information bits to the channel state information providing unit 217. The encoded data is output by encoding according to a coding scheme according to the control. In this case, the modulation and coding unit 215 performs modulation such as frequency conversion to contain a low frequency signal that transfers the information bits provided by the data scheduling unit 213 to a carrier of a predetermined form prior to coding. In this case, the modulation and coding unit 215 performs modulation with different characteristics based on the channel state information provided by the channel state information providing unit 217 for adaptive modulation.

The channel state information providing unit 217 controls the voice scheduling unit 211, the data scheduling unit 213, and the modulation and coding unit 215 and modulates and codes the MCS according to the determined modulation coding and scheme (MCS). 215 provides a coding scheme. Here, the channel state information may be provided from the receiving device, for example.

The transmission data processor 220 may include a fast Fourier inverse transform (IFFT) unit, a parallel / serial (P / S) converter, and a guard interval insertion unit. The fast Fourier inverse transform unit combines multiple subcarriers by performing inverse transform on the encoded data provided by the modulation and coding unit 215. The parallel / serial converter receives the signals of the multiple channels provided by the fast Fourier inverse converter, converts them in series, and outputs them. The guard interval insertion unit receives a signal provided by the parallel / serial conversion unit, inserts a guard interval signal, and outputs the guard interval signal. Here, the guard interval is inserted to remove interference between the OFDM symbol transmitted at the previous OFDM symbol time and the current OFDM symbol to be transmitted at the current OFDM symbol time when the OFDM symbol is transmitted in the OFDM communication system.

6 is a diagram illustrating an operation process of the voice scheduling unit of FIG. 3.

Referring to FIG. 6 together with FIGS. 3 and 4, the initial RB allocator 300 allocates resource blocks based on initial scheduling and priority to packets provided by the first buffer unit 201 (S601). .

At this time, if resources based on priorities are allocated to the packets, the packet inspecting unit 400 preferably sets the index i of the packets to 1 (S603).

The packet inspecting unit 400 selects at least one of the transmitted packets and checks whether the capacity of the resource allocated to the selected packet or the capacity Ci of the resource block is greater than or equal to the length Li of the selected packet (S605). In this case, the packet inspecting unit 400 may sequentially select packets with respect to the transmitted packets, or may randomly select the packets. Through this process, it is guaranteed that the capacity Ci of the resource allocated to the packet is sufficiently larger than the length Li of the packet.

If the capacity Ci of the resource allocated to the selected packet is greater than or equal to the length Li of the selected packet, the packet acknowledgment unit 410 may have a difference between the capacity Ci of the resource allocated to the selected packet and the length Li of the selected packet. If it is within the predetermined value δ (S607), the current resource allocation result for the selected packet is accepted (S609). This process ensures that the capacity of the resource allocated to the packet is not excessively exceeded.

Here, the variable δ representing a predetermined value functions as a limiting device applied to the difference between the packet length Li and its allocated capacity Ci. If the variable δ is set too small, it means that the restriction is very strictly applied, meaning that the capacity of the resource is almost completely used and there is little wasted capacity.

By adjusting such a variable δ, the data rate of the MAC layer can be minimized. If the variable δ is too large, the constraints are loose and it is easy to satisfy the condition. In this case, the data rate of the MAC layer is not very high, but the fairness of the compromise between users is increased.

If the current resource allocation result for the selected packet is approved, the packet inspecting unit 400 preferably increases the index of the packet by 1 (S611).

At this time, if the number of increased indexes is less than or equal to the number of candidate packets remaining to be transmitted (S613), the packet inspecting unit 400 selects at least one of the candidate packets and the capacity of the resource allocated to the selected candidate packet is selected from the selected candidate packets. It is preferable to check whether or not the length (S605). If the number of increased indexes is greater than the number of candidate packets remaining to be transmitted, the compensation step of the LTE system according to an embodiment of the present invention ends.

If the length of the selected packet or the length Li of the selected candidate packet exceeds the capacity Ci of the resource allocated to the selected packet or the selected candidate packet (S605), the resource release unit 420 may select the selected packet or the selected packet. The resource or resource block allocated to the candidate packet is released (S615). The resource reassignment unit 430 reallocates the resources released by the resource release unit 420 among other packets, and related packets are provided to the packet inspecting unit 400 to increase the index by one.

In addition, the surplus resource release unit 440 may determine that a difference between the capacity Ci of the resources allocated to the selected packet or the selected candidate packet and the length Li of the selected packet or the selected candidate packet is greater than the predetermined value δ (S607). In step S617, the excess resources of the resources allocated to the selected packet or the selected candidate packet are released. At this time, the surplus resource reassignment unit 450 may be reassigned among other candidate packets remaining to transmit the resources released by the surplus resource release unit 440. The relevant packets are provided to the packet acknowledgment unit 410 and approved.

As described above, the scheduling and resource allocation unit and the scheduling and resource allocation method according to an embodiment of the present invention can reduce the loss rate of the packet by considering the potential effect that the length of the packet can have on the resources. .

In addition, by trying to match the length of the packet and the resource for transmitting the packet it is possible to improve the MAC packet data rate and increase the spectral efficiency.

In addition, by adjusting the value of the variable δ, it is possible to control the compromise between the data rate and fairness of the system.

7 is a diagram illustrating an operation process of the data scheduling unit of FIG. 5.

Referring to FIG. 7 along with FIG. 5, the RB analysis and RB reassigner 500 analyzes the allocated RB based on the priority in the voice scheduling unit 211, finds a user having a good channel gain, and finds a second buffer. The resource for the data packet provided by the unit 203 is reallocated (S701).

In addition, the second compensation unit 510 compensates for the reallocated resource blocks by the RB analysis and RB reassignment unit 500 (S702 to S713). The operation process of the second compensator 510 is not significantly different from the operation process of the first compensator 310 illustrated in FIG. 6. Therefore, the second compensator 510 is replaced with the contents of the first compensator 310 described with reference to FIG. 6, and further description thereof will be omitted.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more. In addition, although all of the components may be implemented in one independent hardware, each or all of the components may be selectively combined to perform some or all functions combined in one or a plurality of hardware. It may be implemented as a computer program having a. Codes and code segments constituting the computer program may be easily inferred by those skilled in the art. Such a computer program is embodied in an embodiment of the present invention by being stored in a computer readable storage medium (Computer Readable Media) to be read and executed by a computer. The storage medium of the computer program may include a magnetic recording medium, an optical recording medium, a carrier wave medium, and the like.

In addition, the terms "comprise", "comprise" or "having" described above mean that the corresponding component may be inherent unless specifically stated otherwise, and thus excludes other components. It should be construed that it may further include other components instead. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. Terms used generally, such as terms defined in a dictionary, should be interpreted to coincide with the contextual meaning of the related art, and shall not be interpreted in an ideal or excessively formal sense unless explicitly defined in the present invention.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Embodiments of the present invention are applicable to a transmitting apparatus for providing a voice and data service in a mobile communication system and a service providing method using the transmitting apparatus. First, characteristics of a voice packet such as a fixed length and sensitivity to delay By considering this, it is possible to keep the packet loss rate of the VolP traffic as small as possible and maximize the data rate of the data packet. Second, some of the schemes according to embodiments of the present invention may be well suited to most existing scheduling algorithms for LTE systems. That is, the scheme according to the embodiment of the present invention will be improved and complemented with other scheduling algorithms. Third, by considering the potential impact that packet length can be placed on a resource, embodiments of the present invention may reduce the packet loss rate for both voice and data packets, and may also utilize RB resources efficiently. Fourth, according to an embodiment of the present invention, an adjustable parameter Vmax is provided to provide a compromise of the allocated resource between voice and data traffic. Operators will be able to adjust the performance for voice and data through this parameter.

100: eNodeB 101: packet classifier
103, 200: buffer section 105: scheduler
110: UE 201: first buffer unit
203: second buffer unit 210: scheduling and resource block allocation unit
211: voice scheduling unit 213: data scheduling unit
215: modulation and coding unit 217: channel state information providing unit
220: transmission data processing unit 230: transmission antenna

Claims (17)

Receives a voice packet for voice service users and first channel state information (CSI) of the mobile communication terminal of the voice service users to analyze the voice packet, and Vmax resource blocks of all N _C resource blocks to the voice Priority allocation for the packet, and checking the length of the voice packet to which the Vmax resource blocks are allocated, the Vmax resource blocks to the priority determined according to the analysis results of the first channel state information and the voice packet Voice scheduling unit is made according to the assignment;
Receiving a data packet for data service users and second channel state information of the mobile communication terminal of the data service users, analyzing the Vmax resource blocks to find a user having the maximum channel gain, and then providing the user with the N Allocating remaining resource blocks except for Vmax resource blocks among the _C total resource blocks for the data packet and checking a length of the data packet to which the remaining resource blocks are allocated, the remaining resource blocks are in the second channel state. A data scheduling unit in which allocation is made according to the information;
Receive a series of information bits for the voice packet and the data packet and the first and second channel state information, and receive the series of information bits in different ways according to the first and second channel state information. A modulation and coding unit for modulating and encoding and outputting encoded data; And
A channel state information providing unit providing the first and second channel state information to the voice scheduling unit, the data scheduling unit, and the modulation and coding unit, respectively.
Transmitter for providing voice and data services in a mobile communication system comprising a. The method of claim 1,
The transmitting device further includes a transmission data processing unit for receiving the encoded data, converting the encoded data, and providing the encoded data to the mobile communication terminal of the voice service users and the data service users.
The transmission data processing unit,
A fast Fourier inverse transform unit for receiving the encoded data and performing fast Fourier inverse transform to combine multiple subcarriers;
A parallel / serial converter for receiving signals of multiple channels provided by the fast Fourier inverse converter and converting the signals in series; And
A guard interval insertion unit receiving the signal provided by the parallel / serial converter and inserting a guard interval signal and outputting the guard interval signal to a transmitting antenna.
Transmitter for providing voice and data services in a mobile communication system comprising a. The method of claim 1,
The voice scheduling unit
An initial resource block allocator for analyzing the voice packet and allocating the Vmax resource blocks to the voice packet first; And a first compensator for checking a length of the voice packet and compensating the Vmax resource blocks allocated to the voice packet according to a result of the check.
Transmitter for providing voice and data services in a mobile communication system comprising a. The method of claim 1,
The data scheduling unit
A resource block analysis and resource block reassignment unit for analyzing the Vmax resource blocks and allocating the remaining resource blocks to the data packet according to a result of the analysis; And
A second compensator for checking a length of the data packet and compensating for the remaining resource block allocated to the data packet according to a result of the checking
Transmission apparatus for providing voice and data services in a mobile communication system, including. The method according to claim 3 or 4,
The first compensator and the second compensator
A packet inspecting unit checking whether a capacity of a resource block allocated to a transmitted packet is greater than or equal to the length of the packet; And
If the capacity of the resource block allocated to the packet is greater than or equal to the length of the packet, if the difference between the capacity of the resource block allocated to the packet and the length of the packet is within a predetermined value, the current allocation result for the packet is acknowledged. Packet acknowledgment
Transmitter for providing voice and data services in a mobile communication system comprising a. The method of claim 5,
The transmitting device further includes a resource release unit for releasing the resource block of the packet when the length of the packet exceeds the capacity of the resource block allocated to the packet. Transmission device for providing a. The method of claim 6,
The transmitting device further includes a resource reallocating unit for reallocating the released resource block among other packets. The method of claim 5,
And a redundant resource release unit for releasing excess resource blocks of the packet when the difference between the capacity of the resource block allocated to the packet and the length of the packet is greater than the predetermined value. Transmission apparatus for providing a data service. The method of claim 8,
And a surplus reallocation unit for reallocating the surplus resource block of the released packet among candidate packets. The method of claim 1,
The voice packet includes a common voice packet containing all information of a word and a VAD packet containing little information of the word,
And the voice scheduling unit schedules the common voice packet before the VAD, and has a priority over the VAD packet. Receives a voice packet for voice service users and first channel state information (CSI) of the mobile communication terminal of the voice service users to analyze the voice packet, and Vmax resource blocks of all N _C resource blocks to the voice Priority allocation for the packet, and checking the length of the voice packet to which the Vmax resource blocks are allocated, the Vmax resource blocks to the priority determined according to the analysis results of the first channel state information and the voice packet A voice packet scheduling step of assigning the voice packets;
The receiving a second channel state information for the mobile terminal of the data packet and the data service user for the data service users, and taking the analysis of the Vmax of the resource blocks to locate the user with the largest channel gain for the user N _C Allocating remaining resource blocks except for Vmax resource blocks among the total resource blocks for the data packet, and checking the length of the data packet to which the remaining resource blocks are allocated, the remaining resource block is the second channel state information. A data packet scheduling step of allocating data according to the allocation; And
Receive a series of information bits for the voice packet and the data packet and the first and second channel state information, and receive the series of information bits in different ways according to the first and second channel state information. Modulate and encode to generate encoded data.
A service providing method of a transmitting device for providing a voice and data service in a mobile communication system comprising a. The method of claim 11,
The voice packet scheduling step includes a first compensation step of checking a length of the voice packet to which the Vmax resource blocks have been allocated and performing compensation for the Vmax resource blocks allocated according to the result of the checking,
The data packet scheduling step includes a second compensation step of checking a length of the data packet to which the remaining resource blocks are allocated and performing compensation for the remaining resource blocks allocated according to the checked result.
A service providing method of a transmitting device for providing a voice and data service in a mobile communication system comprising a. The method of claim 12,
The first compensation step and the second compensation step are respectively
Checking whether the capacity of the resource block allocated to the packet to be transmitted is greater than or equal to the length of the packet; And
If the capacity of the resource block allocated to the packet is greater than or equal to the length of the packet, acknowledging a current allocation result for the packet when the difference between the capacity of the resource allocated to the packet and the length of the packet is within a predetermined value. To
A service providing method of a transmitting device for providing a voice and data service in a mobile communication system comprising a. The method of claim 13,
The service providing method further comprises releasing a resource of the packet when the length of the packet exceeds the capacity of the resource allocated to the packet. A service providing method of a transmitting device for performing. The method of claim 14,
The step of releasing the resource of the packet further comprises the step of reallocating the resource block of the released packet among other packets further comprising: How we deliver the service. The method of claim 13,
The service providing method further comprises the step of releasing the surplus resources of the packet when the difference between the capacity of the resource block allocated to the packet and the length of the packet is larger than the predetermined value. A service providing method of a transmitting device for providing a voice and data service. The method of claim 16,
Releasing the surplus resource of the packet further includes reallocating the surplus resource block of the released packet among candidate packets. How to service your device.

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