CN111787564B - An energy consumption assessment and optimization method - Google Patents

Abstract

The present invention relates to an energy consumption evaluation and optimization method of an extended discontinuous reception mechanism (eDRX). It belongs to the field of narrowband Internet of Things. The present invention includes the following steps: S1: when the terminal adopts the extended discontinuous reception mechanism (eDRX), establishes a Markov model with the terminal working state as a state variable; S2: when the terminal has data to transmit, it tries to randomly access the network; S3: When the random access of the terminal fails, the terminal needs to perform a backoff process, and the backoff value is determined by the number of re-access times and the initial backoff value; S4: When the backoff value increases linearly as mentioned above, the above energy evaluation model is used for verification. The invention can effectively and comprehensively evaluate the energy consumption of the terminal, effectively reduce the energy consumption of the terminal, improve the utilization rate of battery energy, and finally improve the life of the terminal.

Description

An energy consumption assessment and optimization method

technical field

The invention belongs to the field of narrowband Internet of Things, and relates to an energy consumption evaluation and optimization method of an extended discontinuous acceptance mechanism (eDRX).

Background technique

Narrowband Internet of Things (NB-IOT) aims to enhance indoor coverage, support a large number of low-throughput devices, low latency sensitivity, ultra-low-cost, low-power devices, and network architecture. In order to achieve its set target of low delay sensitivity and low power consumption, an extension to the power saving of the original DRX mechanism in LTE is adopted. The extended discontinuous reception mechanism (eDRX) has a longer paging cycle than the DRX mechanism. The eDRX mechanism stipulates that in each eDRX cycle, the terminal can receive downlink data only within the set paging time window, and the terminal is in a dormant state during the rest of the time and does not accept downlink data. In each eDRX cycle, there is a paging time window PTW, and the terminal always monitors the paging channel in this window in order to receive downlink data. In this mode, the terminal device can be considered to be reachable at any time.

The process of random access of NB-IoT is divided into four parts. ① Preamble sequence transmission, ② Random access response, ③ MSG3 sends (RRC Connection Request) ④ Conflict resolution message. In short, it can be described as after the access preamble sequence is sent, the UE monitors the PDCCH channel to see if there is an RAR message replied by the base station, if no RAR message or the preamble sequence index in the RAR message is received within the specified time range If it does not match its own, it is considered that the access has failed. If the access fails but the maximum number of attempts has not been reached, try sending the preamble again. However, the UE needs to delay for a period of time to perform the next preamble access, and the system design backoff time is a fixed value.

The extended discontinuous reception mechanism (eDRX) adopted by the Narrowband Internet of Things (NB-IOT) can theoretically save energy consumption, but at present, when testing the energy consumption of NB-IOT terminals, the established model is not comprehensive enough to be effective and objective. To estimate the energy consumption of the terminal during data transmission, it is very meaningful to design a model so that we can estimate the energy consumption of the NB-IoT terminal more comprehensively. Furthermore, the current energy optimization algorithm based on discontinuous acceptance mechanism is oriented to H2H and not suitable for M2M. Therefore, it is very meaningful to design an energy optimization mechanism to optimize the terminal life of NB-IoT.

SUMMARY OF THE INVENTION

In view of this, the present invention provides an energy consumption evaluation and optimization method of the extended discontinuous reception mechanism (eDRX), so as to solve the more accurate energy consumption evaluation of the narrowband Internet of Things terminal during data transmission and the problem based on excessive energy consumption. question.

To achieve the above object, the present invention provides the following technical solutions:

An energy consumption evaluation and optimization method involving extended discontinuous acceptance mechanism (eDRX), including the following steps:

S1: When the terminal adopts the extended discontinuous reception mechanism (eDRX), establish a Markov model with the terminal working state as the state variable;

S2: When the terminal has data to transmit, it tries to access the network randomly;

S3: When the random access of the terminal fails, the terminal needs to perform a back-off process, and the back-off value is determined by the number of re-access times and the initial back-off value;

S4: When the back-off value increases linearly as mentioned above, the above energy evaluation model is used for verification.

Further, in step S1, when the terminal adopts the extended discontinuous reception mechanism (eDRX), its working state is divided into an idle state, a PSM state, and a connected state. The connection state is further divided into the data transmission state and the random access state. In the random access state, (i,0)i∈[0,m] represents the ith attempt of the terminal device to access the network, i,ki∈0, m,k∈0,W _i -1, represents the k-th backoff of the i-th re-access. m represents the maximum number of re-access allowed, and _Wi represents the maximum time that the device can back off when encountering an access collision. The CR state indicates that the terminal performs a secure connection confirmation. The Markov model is composed of the above states for energy consumption analysis.

Further, in step S2, if the terminal detects that there is data to be transmitted, it enters a random access state, and attempts random access for the first time. This process includes two processes of accessing the network and confirming a secure connection.

Further, in step S3, when the device is in step S2, if it does not encounter a random access collision or a secure connection failure, it normally enters the data transmission phase, and if a collision occurs in the access process or an error occurs in the secure connection, the terminal Enter the backoff process. The maximum backoff time value follows a linear process, that is, W _i =i*W _min , where W _min is the minimum value randomly selected when the terminal performs the first back off and conforming to the narrowband Internet of Things system.

Further, in step S4, after the terminal performs the linear backoff process and successfully accesses the network, it estimates the current energy consumption according to the energy consumption model proposed in step S1.

The beneficial effects of the present invention are: compared with the existing energy evaluation model for Narrowband Internet of Things (NB-IOT) terminals during data transmission, the present invention is more comprehensive, and the specific analysis of the specific process of random access is more conducive to synthesis Evaluate energy consumption. In the energy optimization, the optimization-related parameters are adopted, that is, the back-off time is optimized to save energy consumption. At the same time, the back-off time is determined by linearly increasing, which also reduces the influence of the back-off time value on the energy consumption of the terminal.

Description of drawings

In order to make the purpose, technical solutions and beneficial effects of the present invention clearer, the present invention provides the following drawings for description:

1 is a schematic flowchart of an embodiment of the present invention;

Fig. 2 is a model diagram of energy consumption evaluation and optimization based on the extended discontinuous acceptance mechanism (eDRX);

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Aiming at the problem of energy consumption required by a narrowband Internet of Things terminal when transmitting data, the present invention proposes an energy consumption evaluation and optimization method involving an extended discontinuous reception mechanism (eDRX). Compared with the existing energy evaluation models, the proposed model can evaluate the energy consumption of equipment relatively comprehensively. The energy consumption evaluation and optimization model based on the extended discontinuous acceptance mechanism (eDRX) is shown in Figure 2.

The process of an energy consumption evaluation and optimization method of the extended discontinuous acceptance mechanism (eDRX) involved in the present invention is shown in FIG. 1 .

As shown in Figure 1, an energy consumption evaluation and optimization method involving the Extended Discontinuous Acceptance Mechanism (eDRX), the method includes the following steps:

S1: When the terminal adopts the extended discontinuous reception mechanism (eDRX), establish a Markov model with the terminal working state as the state variable;

S2: When the terminal has data to transmit, it tries to access the network randomly;

S3: When the random access of the terminal fails, the terminal needs to perform a back-off process, and the back-off value is determined by the number of re-access times and the initial back-off value;

S4: When the back-off value increases linearly as mentioned above, the above energy evaluation model is used for verification.

When the terminal adopts the extended discontinuous reception mechanism (eDRX), its working state is divided into an idle state, a PSM state, and a connected state. The connection state is further divided into the data transmission state and the random access state. In the random access state, (i,0)i∈[0,m] represents the ith attempt of the terminal device to access the network, i,ki∈0, m,k∈0,W _i -1, represents the k-th backoff of the i-th re-access. m represents the maximum number of re-access allowed, and _Wi represents the maximum time that the device can back off when encountering an access collision. The CR state indicates that the terminal performs a secure connection confirmation. The above states are composed of a Markov model for energy consumption analysis. The specific model is shown in Figure 2.

If the terminal detects that there is data to be transmitted, it enters the random access state and tries the first random access. This process includes two processes of accessing the network and confirming the secure connection.

When the device is in step S2, if it does not encounter random access collisions or secure connection failures, it normally enters the data transmission phase, and if the access process collides or security connection errors occur, the terminal enters the back-off process. The maximum backoff time value follows a linear process, that is, W _i =i*W _min , where W _min is the minimum value randomly selected when the terminal performs the first back off and conforming to the narrowband Internet of Things system.

After the terminal performs the linear backoff process and successfully accesses the network, it estimates the current energy consumption according to the energy consumption model proposed in step S1.

Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should Various changes may be made in details without departing from the scope of the invention as defined by the claims.

Claims (1)

1. An energy consumption evaluation and optimization method based on an extended discontinuous reception mechanism (eDRX), which is characterized in that: the specific steps of an NB-IoT terminal for effectively optimizing and evaluating the energy consumption of the NB-IoT terminal during data transmission are as follows:

s1: when the terminal adopts eDRX, establishing a Markov model taking the working state of the terminal as a state variable: the working states of the system are IDLE state IDLE, PSM state and connection state Connect, and the connection state is divided into data transmission state TX and random access state RA; in the random access state, (i,0) i ∈ [0, m ∈ >]Represents the ith attempt of the device to access the network, (i, k) i ∈ [0, m]，k∈[0，W _i -1]Denotes a k-th backoff of the ith re-access, m denotes a maximum number of re-accesses allowed, W _i Representing the maximum time that the device can back off when encountering an access collision; cr (i) status indicates that the terminal performs secure connection confirmation; p _c Indicating the probability of random access collision, P _e Indicating the probability of error in the secure connection, P _tx Indicating the possibility of data transmission at the time of Ti expiration, P _i Representing the probability of each data transmission failure;

s2: attempting random access to the network when the terminal has data to transmit: if the terminal detects that data is required to be transmitted, the terminal enters a random access state and tries a first random access, and the process comprises two processes of network access and safe connection confirmation;

s3: when the terminal fails in random access, the terminal executes a backoff process, and a backoff value is determined by the number of re-accesses and an initial backoff value: when the device is in step S2, if no random access collision or security connection failure is encountered, the device normally enters a data transmission phase, and if the access process has collision or security connection error, the terminal enters a backoff process; the maximum back-off time value follows a linear process, i.e. W _i ＝i*W _min Wherein W is _min Randomly selecting a minimum value which is in accordance with the narrow-band Internet of things system when the terminal is retreated for the first time;

s4: after the terminal completes the linear back-off process and successfully accesses the network, the terminal estimates the energy consumption at this time according to the energy consumption model proposed in step S1.

Images