CN113853029A

CN113853029A - Multi-element machine type communication random access method based on enhanced PRACH

Info

Publication number: CN113853029A
Application number: CN202110996612.0A
Authority: CN
Inventors: 邵羽丰; 徐忠胜; 董唱
Original assignee: Tianyi Digital Life Technology Co Ltd
Current assignee: Tianyi Digital Life Technology Co Ltd
Priority date: 2021-08-27
Filing date: 2021-08-27
Publication date: 2021-12-28

Abstract

The invention provides a multivariate machine type communication random access method based on an enhanced PRACH. The method comprises the following steps: determining a priority of the MTC device, wherein the priority is divided based on latency sensitivity of the MTC device and comprises at least a high priority, a medium priority and a low priority; receiving broadcasted access control forbidden ACB factors and a Physical Random Access Channel (PRACH) and Physical Uplink Shared Channel (PUSCH) resource allocation scheme which maximizes the access capacity of equipment from a base station; determining whether to initiate a random access procedure based on the priority of the MTC device and the ACB factor.

Description

Multi-element machine type communication random access method based on enhanced PRACH

Technical Field

The invention relates to wireless communication, in particular to a multivariate machine type communication random access method based on an enhanced Physical Random Access Channel (PRACH).

Background

In recent years, with the rapid development of wireless communication, communication services have been developed from conventional person-to-person communication to object-to-object communication. Machine type communication is a key technology for developing the internet of things, during the takeoff of the technology, a new era of communication governs a new open business market, and each Machine Type Communication (MTC) device is no longer an isolated product, but forms an atom of an interconnected, humanized and intelligent era. The third Generation Partnership Project (3rd Generation Partnership Project, 3GPP for short) divides the application field of MTC into 7 major classes, which respectively include: safety monitoring, tracking and positioning, intelligent payment, electronic medical care, remote monitoring, intelligent metering and electronic consumption. For example, the MTC can be applied to the meter reading business of water, electricity and gas, the manual meter reading which is troublesome and laborious is replaced by the intelligent meter reading, and the intelligent meter reading can realize the timed reading of data through a connecting network, so that the automatic detection and control are realized. In addition, the MTC can also be applied to the Internet of vehicles to realize intelligent traffic, the MTC equipment can detect road conditions in real time, monitor and control traffic flow, realize the connection of vehicles and the network and provide an optimal driving path for drivers, so that the problem of traffic jam is relieved, and users can conveniently go out. In addition, emerging industries such as smart homes, wearable devices, smart medicine and the like in the future can be developed rapidly, and machine type communication plays an important role.

The MTC equipment is greatly different from the conventional H2H, the most important feature of MTC communication is that the number of equipment is large, and according to 3GPP, the number of MTC equipment is at least two orders of magnitude of the number of H2H equipment, so that when a large number of MTC equipment simultaneously initiate access requests, access congestion is greatly likely to be caused, thereby causing intolerable delay, packet loss, and service interruption problems, which are not only detrimental to the service quality of MTC communication, but also may affect the communication performance between people, and therefore, a corresponding solution is designed by analyzing the problems and challenges faced by MTC communication, and has a very important meaning for the development of MTC communication.

Therefore, in order to effectively reduce the probability of collision of preambles and improve the access capacity and resource utilization rate of the devices while ensuring the quality of service (QoS) requirements of the MTC devices, it is desirable to provide an improved random access method for multi-component machine type communication.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

The invention provides a random access scheme of multi-element machine equipment based on an enhanced PRACH, wherein the PRACH is a key link for accessing MTC equipment into a network, the enhanced PRACH has the technical advantages that equipment Identity (ID) information and cyclic Redundancy check codes (CRC) for verifying the equipment ID information are mapped onto partial subcarriers of a PRACH protection interval, and the PRACH not only bears a lead code sent by the equipment, but also bears the equipment identity information. And if the base station can correctly detect the equipment identity ID, the base station feeds back random access response information, otherwise, the base station does not transmit the random access response. In addition, the enhanced PRACH technique may assist the base station to detect whether a preamble is selected for use by multiple devices before receiving the scheduling information sent by the devices, thereby avoiding resource waste caused by preamble collision as much as possible and improving resource utilization. In addition, the base station may utilize an Access Control Barring (ACB) mechanism to limit the number of devices initiating access per access slot by broadcasting an ACB control factor prior to device access. The invention considers the different requirements of the multi-element service on the equipment access priority in the machine type communication scene of the multi-element service, uses the ACB mechanism to respectively configure proper control factors for system access control, and designs a new random access method based on the enhanced PRACH technology.

According to an aspect of the present invention, there is provided a wireless communication method performed by a Machine Type Communication (MTC) device, the method comprising:

determining a priority of the MTC device, wherein the priority is divided based on latency sensitivity of the MTC device and comprises at least a high priority, a medium priority and a low priority;

receiving broadcasted access control forbidden ACB factors and a Physical Random Access Channel (PRACH) and Physical Uplink Shared Channel (PUSCH) resource allocation scheme which maximizes the access capacity of equipment from a base station;

determining whether to initiate a random access procedure based on the priority of the MTC device and the ACB factor.

According to one embodiment of the invention, the ACB factor is a value in the range [0,1] determined based on the QoS index of the high priority device.

According to a further embodiment of the present invention, determining whether to initiate a random access procedure based on the priority of the MTC device and the ACB factor further comprises:

if the MTC equipment is high-priority equipment, initiating a random access procedure; and

if the MTC equipment is medium-priority or low-priority equipment, generating a random number between 0 and 1, comparing the generated random number with an ACB factor corresponding to the priority of the MTC equipment, and if the random number is smaller than the ACB factor corresponding to the priority of the MTC equipment, initiating a random access procedure.

According to a further embodiment of the invention, the method further comprises: in response to initiating the random access procedure, performing the following:

transmitting a preamble and a device Identity (ID) to the base station using PRACH resources allocated for the MTC device;

receiving a random access response, RAR, message from the base station in response to the base station successfully decoding the device identity, ID, wherein the RAR message includes a preamble identification corresponding to the transmitted preamble;

transmitting data to the base station using PUSCH resources allocated for the MTC device in response to the RAR message; and receiving an acknowledgement, ACK, from the base station in response to the base station successfully receiving the data.

According to another aspect of the present invention, there is provided a wireless communication method performed by a base station, the method including:

broadcasting an access control barring, ACB, factor corresponding to a priority of a machine type communication, MTC, device, and a physical random access channel, PRACH, and physical uplink shared channel, PUSCH, resource allocation scheme that maximizes device access capacity, wherein the priority is divided based on latency sensitivity of the MTC device and includes at least a high priority, a medium priority, and a low priority;

responding to the MTC device initiating a random access procedure based on the priority of the MTC device and the ACB factor.

According to an embodiment of the present invention, responding to the MTC device initiating a random access procedure based on the priority of the MTC device and the ACB factor further comprises:

receiving a preamble and a device identity, ID, from the MTC device in response to the MTC device initiating a random access procedure;

decoding the device identity ID in response to the received preamble being valid;

transmitting a Random Access Response (RAR) message to the MTC device in response to successfully decoding the device Identity (ID), wherein the RAR message comprises a preamble identification corresponding to the received preamble;

receiving data from the MTC device in response to the RAR message; and

transmitting an acknowledgement ACK to the MTC device in response to successfully receiving the data.

According to a further embodiment of the invention, the ACB factor is a value in the range [0,1] determined based on the QoS index of the high priority device.

According to a further embodiment of the present invention, the PRACH and PUSCH resource allocation schemes are determined with the goal of maximizing device access capacity, with high priority QoS requirements as constraints, where the number of resources scheduled to the PUSCH matches the number of preambles successfully transmitted.

According to yet another aspect of the present invention, there is provided an apparatus for wireless communication, comprising:

a transceiver;

a memory configured to store instructions; and

one or more processors communicatively coupled with the transceiver and the memory, wherein the instructions, when executed, may cause the one or more processors to:

determining a priority of the device, wherein the priority is divided based on latency sensitivity of the device and includes at least a high priority, a medium priority, and a low priority;

determining whether to initiate a random access procedure based on a priority of the device and the ACB factor;

in response to initiating the random access procedure, performing the following:

transmitting a preamble and a device Identity (ID) to the base station using PRACH resources allocated for the device;

transmitting data to the base station using the PUSCH resources allocated for the device in response to the RAR message; and

receiving an Acknowledgement (ACK) from the base station in response to the base station successfully receiving the data.

According to still another aspect of the present invention, there is provided an apparatus for wireless communication, including:

a transceiver;

a memory configured to store instructions; and

receiving a preamble and a device identity ID from the MTC device in response to the MTC device initiating a random access procedure based on a priority of the MTC device and the ACB factor;

receiving data from the MTC device in response to the RAR message; and

Compared with the scheme in the prior art, the enhanced PRACH-based multivariate machine type communication random access method provided by the invention at least has the following advantages:

(1) different from the traditional random access process, the PRACH not only bears the lead code information, but also bears the equipment identity information, if the base station can detect the equipment identity information, the base station transmits the random access response, otherwise, the random access response is not transmitted, thereby avoiding the problem of insufficient utilization of Physical Uplink Shared Channel (PUSCH) resources caused by lead code collision; and

(2) the invention adopts an ACB access control mechanism, carries out priority division on the equipment according to MTC service characteristics, optimizes the resource allocation of the PRACH and the PUSCH by taking the QoS index of the high-priority equipment as constraint and the access capacity as a target, thereby effectively relieving the congestion problem caused by random access of the equipment in a multi-element service scene.

These and other features and advantages will become apparent upon reading the following detailed description and upon reference to the accompanying drawings. It is to be understood that both the foregoing general description and the following detailed description are explanatory only and are not restrictive of aspects as claimed.

Drawings

So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only some typical aspects of this invention and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

Fig. 1 shows a distribution diagram of prioritized MTC devices in a single cell application scenario in a cellular network, according to an embodiment of the invention.

Fig. 2A-2B illustrate the impact of an ACB factor on high priority device QoS according to one embodiment of the invention.

Fig. 3 shows a process flow diagram of an enhanced PRACH-based multivariate machine-type communication random access method according to an embodiment of the present invention.

Fig. 4 shows a flowchart of an enhanced PRACH-based multi-element machine type communication random access method performed by an MTC device according to an embodiment of the present invention.

Fig. 5 shows a diagram of a system including a device supporting enhanced PRACH-based multi-element machine type communication random access according to one embodiment of the present invention.

Fig. 6 shows a flowchart of an enhanced PRACH-based multivariate machine-type communication random access method performed by a base station according to an embodiment of the present invention.

Fig. 7 shows a diagram of a system including a device supporting enhanced PRACH-based multi-element machine type communication random access according to one embodiment of the present invention.

Detailed Description

The present invention will be described in detail below with reference to the attached drawings, and the features of the present invention will be further apparent from the following detailed description.

Fig. 1 illustrates a distribution diagram 100 of prioritized MTC devices in a single cell application scenario in a cellular network, according to an embodiment of the invention. In fig. 1, a cellular base station is located at the center of a cell with a radius of 200m, and large-scale MTC devices are uniformly distributed inside the cell. MTC may refer to a data communication technique that allows devices to communicate with each other or with a base station without human intervention. In some examples, MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay the information to a central server or application that may utilize the information or present the information to a person interacting with the program or application. Examples of applications for MTC devices include: smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, field survival monitoring, weather and geographic event monitoring, queue management and tracking, remote security sensing, physical access control, and transaction-based business charging. The MTC devices in fig. 1 are divided into high priority devices (denoted by asterisks), medium priority devices (denoted by triangles) and low priority devices (denoted by circles). In some cases, the priority classification may be performed according to QoS indicators of the MTC devices, where the QoS indicators may include, for example, average delay and average data packet loss rate. In some cases, different priority devices may access with different probabilities according to the ACB access control factor broadcast by the base station.

The design of ACB access control factors is discussed further below. Different priority devices can access with different ACB control factors, wherein the access probability and the ACB factors have positive correlation. Specifically, if the ACB factor value is small, the access probability will decrease and a limited number of devices may pass the ACB check, thereby resulting in an increased access delay. If the ACB factor value is large, the access probability will increase, which may lead to access congestion. Therefore, in addition to meeting QoS requirements, it is also important to adapt the ACB factor to the traffic load.

Herein, the ACB factor setting may be determined based on the QoS requirements of the high priority device, and benefit hereofPacket loss rate P by average data_dAnd an average delay T_mAs a QoS index. The two index values are determined according to the ACB factor value and the traffic load, wherein the collision probability of the high-priority equipment is shown as the formula 1:

N_i＝N_1,i+p_2,iN_2,i+p_3,iN_3,i (2)

wherein N in formula 2_iRepresenting the average traffic load per time slot, N_j,iIndicating the number of devices waiting for access in the ith time slot of the j-type devices, p_j,iRepresenting the ACB factor of the ith slot of a class j device.

Based on this, the average delay T_mAs shown in equation 3:

wherein N is_maxRepresents the maximum number of retransmissions of the preamble, T₁Indicates the duration of the random access procedure, T₂Indicating the time of the retry when the preamble collision occurs.

Finally, the average data packet loss rate P_dDepending on the collision probability P_collAnd a maximum number of retransmissions N_maxAs shown in formula 4:

in one example, assuming that the total traffic of MTC devices in a slot is 100, where the high, medium and low priority devices are 10, 40, 50, respectively, and T1 and T2 are 17ms and 9ms, respectively, this can be calculated by a complete PRACH procedure (including random access response, contention resolution procedure, average back-off time when preamble collision occurs). Fig. 2A and fig. 2B show the influence of the ACB factor of the medium-low priority on the average data packet loss rate and the average access delay, respectively. As shown in fig. 2A-2B, the packet loss rate and the average access delay value increase as the ACB factor of the medium-low priority device increases. Therefore, the flow of the medium and low priority equipment can be adjusted through the ACB factor, so that the QoS requirement of the high priority equipment is ensured. As can be seen from fig. 2A-2B, the ACB factor can be determined by QoS requirements (e.g., packet loss rate, delay requirement), and by dynamically updating the ACB factor of each slot, the number of medium and low priority devices sending access requests can be limited, thereby controlling congestion.

In addition, the MTC device needs to complete one complete communication through two phases, namely, network access and data transmission, where PRACH channel resources are used for network access and a Physical Uplink Shared Channel (PUSCH) is used for data transmission. At present, a great deal of research on MTC congestion control relates to optimizing distribution of PRACH resources, improving success rate of random access by reducing lead code collision probability and defaulting to the condition that data transmission resources are sufficient. However, in an actual system, the PRACH channel resource and the PUSCH channel resource belong to the same uplink channel resource, the uplink resource is limited, and both the PRACH and PUSCH resources affect the random access performance of the MTC device. Therefore, the invention obtains the optimal allocation proportion of the uplink resource PRACH and the PUSCH channel resource under the condition of taking the maximum access capacity of the service as the target and taking the high-priority QoS requirement as the constraint. The details of the PRACH and PUSCH channel resource allocation will be analyzed in detail below.

As is known, when devices transmitting the same preamble sequence transmit through the same PRACH resource, preamble collision may be caused, resulting in a failure of random access. If the base station allocates a large amount of resources to the PRACH channel, the preamble collision rate may be reduced, but the remaining PUSCH resources of the system are small, which results in that the base station cannot allocate PUSCH resources to all devices that successfully transmit preambles, and the devices cannot successfully access. On the contrary, if the base station allocates a large amount of resources to the PUSCH channel, a large number of devices cannot successfully transmit the preamble, which results in a waste of PUSCH channel resources. Therefore, there is a need for a reasonable allocation scheme of PRACH and PUSCH channel resources in order to maximize the utilization of uplink resources and increase the number of devices that successfully access the network.

Before the random access period starts, the base station allocates uplink resources to PRACH and PUSCH and broadcasts the PRACH configuration to all devices over a broadcast or control channel. Assuming that the total number of Resource Blocks (RBs) per slot is q, the number of RBs allocated to PRACH is l, the number of RBs allocated to PUSCH is u, and assuming that n RBs are required to constitute one PUSCH and b RBs are required to transmit one preamble, u RBs may be constituted

One PUSCH, l RBs can be transmitted

A preamble. Thus, the overall resource efficiency r is defined as the ratio of the number of RBs used for successful random access for machine-type communication to the total number of RBs, as shown in equation 5:

where C denotes the number of devices successfully randomly accessed, b + n denotes the total number of RBs required for one successful random access, and q denotes the total number of RBs per slot.

H and I represent the number of available PUSCHs and the number of successfully transmitted preambles, respectively, as shown in equations 6 and 7:

the resource allocation efficiency is maximum when the number of PUSCHs is equal to the number of successfully transmitted preambles. The attestation process is described in detail below. As described above, assuming that n RBs constitute one PUSCH, u RBs may constitute

One PUSCH, b RBs transmit one preamble sequence, then l RBs can transmit

A preamble. P_sFor the probability of successful transmission of the preamble, the number of successfully transmitted preambles is

Thus, the value of u/n can be shown as the following equation 8:

P_sthe value of l/b can be shown as the following formula 9:

where dec () represents the fractional part in parentheses. In practical applications, the number of available PUSCHs and the number of successfully transmitted preambles are much larger than 1, so the integer part is much larger than the fractional part, and therefore the fractional part is negligible.

Therefore, when the number of PUSCHs is equal to the number of preambles successfully transmitted, i.e., H ═ I, the following is obtained and the like

Formula 10:

neglecting the fractional part followed by u/n ═ P_sl/b, therefore, the resource allocation efficiency can be as shown in equation 11:

if H < I, u/n < P_sl/b, the resource allocation efficiency is shown as formula 12:

similarly, if H > I, u/n > P_sl/b, the resource allocation efficiency is shown as formula 13:

in summary, when H ═ I, i.e. the number of PUSCHs is equal to the number of successfully transmitted preambles, the resource allocation efficiency r takes a maximum value.

Since the objective of the optimization model of the resource allocation scheme of the present invention is to maximize the overall access capacity of the traffic, the uplink PRACH and PUSCH channel resource allocation problem can be expressed as an optimization problem as shown in equation 14 below:

constraint 1: n is a radical of_i＝N_1,i+p_2,iN_2,i+p_3,iN_3,i

Constraint 2: p is more than or equal to 0_j,i≤1 (14)

Assuming that the random access request can be reinitiated in the next period after the random access of the device in the current period fails until the access is successful, the number of retransmissions is infinite, and thus the delay can be as shown in the following equation 15:

and when the equipment successfully sends the preamble and has a corresponding PUSCH for service data information transmission, the equipment is successfully accessed to the network. In order to maximize the resource allocation efficiency, the number of resources scheduled to the PUSCH should match the number of successfully transmitted preambles under the condition that the total resources are limited, i.e., as follows

Formula 16:

since the left side of the equation 16 is a nonlinear function, it is difficult to directly solve the optimal solution l, since l is [1, q-1 ]]So that the optimal solution l can be obtained by exhaustive search_opt，l_optMay be represented by the following formula 17:

thus, the number of devices C that have been successfully accessed last_optThe minimum value of the PUSCH number and the successfully transmitted preamble number is as shown in equation 18 below:

fig. 3 shows a process flow diagram of an enhanced PRACH-based multi-element machine-type communication random access method 300 according to an embodiment of the present invention. The random access procedure of method 300 includes the following steps:

step S1: a plurality of MTC devices to be accessed may be divided into high priority devices, medium priority devices, and low priority devices according to QoS metrics (e.g., latency sensitivity requirements), as shown in fig. 1.

Step S2: the base station may calculate the ACB control factor p based on the high priority QoS index_j,iAnd channel resource allocation between PRACH and PUSCH. For example, the base station may determine the ACB control factor p based on the QoS requirements of the MTC devices using the aforementioned design method of the ACB access control factor_j,i. In addition, the base station may obtain the optimal allocation ratio of the uplink resource PRACH and the PUSCH channel resource under the condition that the maximum access capacity of the service is targeted and the high priority QoS requirement is a constraint as described above. Subsequently, the ACB control factor p is determined_j,iAnd PRACH andafter channel resource allocation between PUSCHs, a base station may broadcast p to multiple MTC devices to be accessed_j,iAnd an uplink channel resource allocation result.

Step S3: the high priority device may have direct access. The medium priority device can generate a random number alpha between 0 and 1₂If α is₂＜p_2,iIf not, waiting for the next random access time slot to initiate access again. The low priority device can generate a random number alpha between 0 and 1₃If α is₃＜p_3,iIf not, waiting for the next random access time slot to initiate access again.

Step S4: the MTC device to be accessed can randomly and equally select a preamble from an available preamble set, and send the preamble and a device Identity (ID) to the base station through the PRACH channel resource allocated by the base station.

Step S5: the base station may first calculate a Power Delay Profile (PDP) of the preamble to detect whether the preamble is valid. If the preamble is valid, the base station starts decoding the device ID. If the device ID can be successfully decoded, indicating that there is no co-channel interference of the device at this time, the base station may consider that the preamble is selected by only one device, and the base station may then schedule the PUSCH and send a corresponding random access response RAR message. Otherwise, the preamble is regarded as a collision by the base station, the preamble is simultaneously selected by the multiple devices, the base station stops sending the corresponding random access response RAR message, and returns to step S3 to wait for the next random access slot to initiate access again. The RAR message may include, for example, a preamble identification, Timing Advance (TA), uplink grant, etc., corresponding to the received preamble. TA generally refers to the offset between the start of a received downlink subframe and the start of a transmitted uplink subframe, which is used to ensure that the downlink and uplink subframes are synchronized at the base station.

Step S6: the MTC device to be accessed may find a random access response RAR message including a preamble identifier matching with the preamble transmitted by the MTC device, adjust its own signal transmission time according to the TA value in the RAR message, and transmit traffic data information on a PUSCH channel scheduled by the base station for the MTC device.

Step S7: the base station can monitor the service data information on all PUSCHs, and if the service data information is successfully monitored, the base station sends an Acknowledgement (ACK) to the corresponding MTC equipment. And if the MTC equipment receives the ACK, the MTC equipment successfully sends the service data information. If the MTC device does not receive the ACK, it indicates that the transmission of the service data information in the current period fails, and returns to step S3 to wait for the next random access slot to initiate access again.

Fig. 4 shows a flowchart of an enhanced PRACH-based multi-element machine type communication random access method 400 performed by an MTC device according to one embodiment of the present invention. The method 400 begins at step 401 by determining a priority of MTC devices to be accessed, wherein the priority is divided based on latency sensitivity of the MTC devices and comprises at least a high priority, a medium priority and a low priority. The QoS metrics may include, for example, average delay and average data packet loss rate.

In step 402, an access control barring, ACB, factor corresponding to the priority of the MTC device and a PRACH and PUSCH resource allocation scheme that maximizes device access capacity are received from a base station. In some cases, the PRACH and PUSCH optimal resource allocation schemes may be determined by the base station under constraints of high priority QoS requirements targeting the traffic maximum access capacity, where the number of resources scheduled to the PUSCH matches the number of preambles successfully transmitted.

In step 403, it is determined whether to initiate a random access procedure based on the received ACB factor. In some cases, different priority devices may access with different probabilities depending on the ACB factor broadcast by the base station. For example, a high priority device may access directly, a medium-low priority device may generate a random number, and access may be performed if the ACB factor corresponding to the device is greater than the random number.

At step 404, in response to initiating the random access procedure, a preamble and a device Identity (ID) are transmitted to a base station using PRACH resources allocated for the MTC device.

In step 405, a random access response, RAR, message is received from the base station in response to the base station successfully decoding the device ID, wherein the RAR message includes a preamble identification corresponding to the transmitted preamble.

In step 406, data is transmitted to the base station using the PUSCH resources allocated for the MTC device in response to receiving the RAR message.

In step 407, an acknowledgement ACK is received from the base station in response to the base station successfully receiving the data.

Fig. 5 shows a diagram of a system 500 comprising a device 501 supporting enhanced PRACH-based multi-element machine-type communication random access according to one embodiment of the present invention. The device 501 may be an MTC device as described herein. The device 501 may include components for two-way voice and data communications, including components for transmitting and receiving communications, including an MTC device communication manager 502, an I/O controller 503, a transceiver 504, an antenna 505, a memory 506, and a processor 507. These components may be in electronic communication via one or more buses, such as bus 509.

The MTC device communication manager 502 may determine a priority of MTC devices to be accessed, wherein the priority is divided based on a quality of service, QoS, index of the MTC devices. The MTC device communication manager 502 may receive from the base station an access control barring, ACB, factor corresponding to the priority of the MTC device and a PRACH and PUSCH resource allocation scheme that maximizes device access capacity. The MTC device communication manager 502 may determine whether to initiate a random access procedure based on the received ACB factor and transmit a preamble and a device ID to the base station in response to initiating the random access procedure. The MTC device communication manager 502 may receive a random access response, RAR, message from a base station in response to the base station successfully decoding a device ID, transmit data to the base station using PUSCH resources allocated for the MTC device, and receive an acknowledgement, ACK, from the base station in response to the base station successfully receiving the data.

The I/O controller 503 may manage input and output signals of the device 501. In some cases, I/O controller 503 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. The transceiver 504 may communicate bi-directionally via one or more antennas, wired or wireless links. In some cases, the wireless device may include a single antenna 505. However, in some cases, the device may have more than one antenna 505, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The memory 2430 may include Random Access Memory (RAM) and Read Only Memory (ROM). The memory 506 may store computer-executable code 508 comprising instructions that, when executed, cause the processor to perform various functions described herein. The processor 507 may include, for example, a general purpose processor, a DSP, a Central Processing Unit (CPU), a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof. In some cases, the processor 507 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into processor 507. The processor 507 may be configured to execute computer readable instructions stored in a memory (e.g., memory 506) to cause the device 501 to perform various functions to support enhanced PRACH-based multi-component machine-type communication random access. Code 508 may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communications. Code 508 may be stored in a non-transitory computer-readable medium, such as a system memory or other type of memory. In some cases, code 508 may not be directly executable by processor 507, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

Fig. 6 shows a flow diagram of an enhanced PRACH-based multi-element machine type communication random access method 600 performed by a base station according to one embodiment of the present invention. The method 600 begins at step 601 by broadcasting an ACB factor corresponding to a priority of MTC devices, wherein the priority is divided based on latency sensitivity of the MTC devices and includes at least a high priority, a medium priority, and a low priority, and a PRACH and PUSCH resource allocation scheme that maximizes device access capacity.

In step 602, a preamble and a device ID are received from an MTC device in response to the MTC device initiating a random access procedure based on an ACB factor.

In step 603, the device ID is decoded in response to the received preamble being valid. In some cases, if the base station successfully decodes the device ID, it may determine that the preamble is selected by only one device, the base station may then schedule the PUSCH and transmit the corresponding RAR message, otherwise it may determine that the preamble is selected by multiple devices simultaneously, a preamble collision occurs, and the base station will stop transmitting the corresponding RAR message.

In step 604, a RAR message is transmitted to the MTC device in response to successfully decoding the device identity ID, wherein the RAR message includes a preamble identification corresponding to the received preamble.

In step 605, data is received from the MTC device in response to the RAR message.

At step 606, an acknowledgement ACK is transmitted to the MTC device in response to successfully receiving the data.

Fig. 7 shows a diagram of a system 700 including a device 701 supporting enhanced PRACH-based multi-element machine type communication random access, according to an embodiment of the present invention. Device 701 may be a base station as described herein. Device 701 may include components for two-way voice and data communications, including components for transmitting and receiving communications, including a base station communications manager 702, a transceiver 703, an antenna 704, a memory 705, and a processor 706. These components may be in electronic communication via one or more buses, such as bus 707.

The base station communication manager 702 may broadcast an ACB factor corresponding to a priority of MTC devices, wherein the priority is divided based on a quality of service, QoS, indicator of the MTC devices, and a PRACH and PUSCH resource allocation scheme that maximizes device access capacity. The base station communication manager 702 may receive a preamble and a device ID from an MTC device in response to the MTC device initiating a random access procedure based on an ACB factor. The base station communications manager 702 may determine that the received preamble is valid and decode the device ID. The base station communication manager 702 may transmit a RAR message to the MTC device upon successful decoding, receive data from the MTC device, and transmit an acknowledgement ACK to the MTC device in response to successfully receiving the data.

The transceiver 703 may communicate bi-directionally via one or more antennas, wired or wireless links. In some cases, the wireless device may include a single antenna 704. However, in some cases, the device may have more than one antenna 704, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The memory 705 may include Random Access Memory (RAM) and read-only memory (ROM). The memory 705 may store computer-executable code 708 comprising instructions that, when executed, cause the processor to perform various functions described herein. The processor 706 may include, for example, a general purpose processor, a DSP, a Central Processing Unit (CPU), a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof. In some cases, the processor 706 may be configured to operate the memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 706. The processor 706 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 705) to cause the apparatus 701 to perform various functions in support of enhanced PRACH-based multi-component machine-type communication random access. Code 708 may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communications. Code 708 may be stored in a non-transitory computer-readable medium, such as a system memory or other type of memory. In some cases, the code 708 may not be directly executable by the processor 706, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

What has been described above includes examples of aspects of the claimed subject matter. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the claimed subject matter, but one of ordinary skill in the art may recognize that many further combinations and permutations of the claimed subject matter are possible. Accordingly, the disclosed subject matter is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.

Claims

1. A method of wireless communication performed by a Machine Type Communication (MTC) device, the method comprising:

2. The method of claim 1, wherein the ACB factor is a value in the range [0,1] determined based on a QoS metric of a high priority device.

3. The method of claim 2, wherein determining whether to initiate a random access procedure based on the priority of the MTC device and the ACB factor further comprises:

4. The method of claim 1, wherein the method further comprises: in response to initiating the random access procedure, performing the following:

5. A method of wireless communication performed by a base station, the method comprising:

6. The method of claim 5, wherein responding to the MTC device initiating a random access procedure based on the priority of the MTC device and the ACB factor further comprises:

receiving data from the MTC device in response to the RAR message; and

7. The method of claim 5, wherein the ACB factor is a value in the range [0,1] determined based on a QoS metric of a high priority device.

8. The method of claim 5, wherein the PRACH and PUSCH resource allocation scheme is determined with a target of maximizing device access capacity, constrained by high priority QoS requirements, wherein a number of resources scheduled to the PUSCH matches a number of successfully transmitted preambles.

9. An apparatus for wireless communication, comprising:

a transceiver;

a memory configured to store instructions; and

10. An apparatus for wireless communication, comprising:

a transceiver;

a memory configured to store instructions; and

receiving data from the MTC device in response to the RAR message; and