无线个人区域网与其它无线设备共存实践

802.15.2

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"802.15.2-2003是IEEE发布的一个标准，全称为‘IEEE Recommended Practice for Information technology—Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements Part 15.2: Coexistence of Wireless Personal Area Networks with Other Wireless Devices Operating in Unlicensed Frequency Bands’。该标准主要关注无线个人区域网络（WPANs）与其他在未授权频段运行的无线设备之间的共存问题。" 本文档详细阐述了802.15.2标准，该标准由IEEE计算机学会赞助，并由LAN/MAN标准委员会支持。该标准旨在促进不同无线技术在共享未授权频谱时的和谐共存，减少干扰并提高整体网络效率。802.15.2标准适用于各种无线个人区域网络，如蓝牙、Zigbee等，这些技术通常在免许可的频率范围内操作，例如2.4GHz ISM频段。 802.15.2标准包含了多个关键概念和技术，包括： 1. **频谱管理**：定义了如何在有限的未授权频段内有效地分配频谱资源，以确保多种无线设备能同时工作而不相互干扰。 2. **通信协议**：制定了协议层间的交互规范，确保不同WPAN技术之间能够进行可靠的数据传输。 3. **共存机制**：提出了多种策略来解决不同无线网络之间的冲突，比如时间分槽、跳频和功率控制。 4. **兼容性和互操作性**：规定了设备间的兼容性要求，使得不同制造商的产品能够在同一环境中无缝协同工作。 5. **安全与隐私**：虽然802.15.2主要关注物理层和媒体访问控制（MAC）层的共存问题，但也会提及一些安全措施，以保护无线通信免受未经授权的访问。 6. **测试和认证**：提供了测试方法和指标，以验证设备是否符合802.15.2标准的要求，确保其在实际部署中的性能。 7. **应用实例**：可能涵盖智能家居、工业自动化、医疗保健、物流跟踪等多个领域的应用案例，展示标准的实际应用场景和优势。 802.15.2标准的制定和实施对于推动无线个人区域网络的发展至关重要，它为设备制造商提供了统一的技术框架，促进了无线设备在复杂电磁环境下的稳定运行和互操作性。随着物联网技术的迅速发展，这个标准在现代无线通信系统中的作用日益凸显。

IEEE

WITH OTHER WIRELESS DEVICES OPERATING IN UNLICENSED FREQUENCY BANDS Std 802.15.2-2003

MLME MAC sublayer management entity

MPDU MAC protocol data unit

MSE medium sharing element

PCF point coordination function

PER packet error rate

PHY physical

PLCP physical layer convergence protocol

pseudorandom noise (e.g., PN code sequence)

PPDU physical protocol data unit

PSDU physical service data unit

PTA packet trafﬁc arbitration

QoS quality of service

QPSK quadrature phase shift keying

RF radio frequency

RLSL recursive least-squares lattice

RSSI

received signal strength indication

RX receive/receiver/receiving

SCO synchronous connection-oriented

SER symbol error rate

SINR signal to interference plus noise ratio (s/(i+n))

SIFS short interframe space

SIR signal to interference ratio (s/i)

SNR signal to noise ratio (s/n)

STA station

TBTT target beacon transmit time

TDMA time-division multiple access

TU time unit (as deﬁned in IEEE Std 802.11, 1999 Edition)

TX transmit/transmitter/transmission

UAP upper address parts

WLAN wireless local area network

WPAN wireless personal area network

3.3 Terminology and variables

Packet:

Is used consistently through this recommendation to mean “medium access control (MAC) frame”

in the context of IEEE 802.11 and “baseband packet” in the context of IEEE 802.15.1.

Packet error rate:

The probability of a packet being received with one or more uncorrected bit errors.

The terminology and variables listed in this subclause are only applicable within this recommended practice. Application of these out-

side of this recommended practice is not applicable. This is why they have their own subclause within this clause.

IEEE

Std 802.15.2-2003 LOCAL AND METROPOLITAN AREA NETWORKS—PART 15.2: COEXISTENCE OF WPANS

adp

next adapted hop-frequency,

adp

is an element of

adp

is an element of

hop

next hop-frequency from the IEEE 802.15.1 hop kernel,

hop

is indexed by an element of

[0, ..., 78]

hop

index that points to the next hop-frequency

number of “bad” channels (

= |

number of “bad” channels kept in the adapted hopping sequence (

= |

number of “bad” channels removed from the adapted hopping sequence (

= |

number of “good” channels (

= |

min

minimum number of hop channels (typically set by regulatory constraints)

p(k)

partition sequence

set of all channels =

union

set of “bad” channels (or indices pointing to the "bad"channels)

set of “bad” channels (or indices) kept in the adapted hopping sequence

(i)

-th channel of

is an element of [0, ...,

-1]

set of “bad” channels (or indices) removed from the adapted hopping sequence

set of “good” channels (or indices pointing to the “good” channels)

(i)

-th channel of

is an element of [0, ...,

-1]

time-out delay

slot time (i.e., 625

4. General descriptions

This clause describes in general terms 1) the issue that this recommended practice attempts to address; 2) the

coexistence mechanisms being recommended to reduce the problem and when to use each coexistence

mechanism; 3) the models used to evaluate the effects; and 4) an overview to the structure of this recom-

mended practice.

4.1 Description of the interference problem

Because both IEEE Std 802.11b-1999 and IEEE 802.15.1-2002 specify operations in the same 2.4 GHz unli-

censed frequency band, there is mutual interference between the two wireless systems that may result in

severe performance degradation. There are many factors that effect the level of interference, namely, the

separation between the WLAN and WPAN devices, the amount of data trafﬁc ﬂowing over each of the two

wireless networks, the power levels of the various devices, and the data rate of the WLAN. Also, different

types of information being sent over the wireless networks have different levels of sensitivity to the interfer-

ence. For example, a voice link may be more sensitive to interference than a data link being used to transfer

a data ﬁle. This subclause gives an overview of the mutual interference problem. Subsequent subclauses

describe the modeling of the mutual interference and give illustrations of the impact of this mutual interfer-

ence on both the WLAN and WPAN networks.

There are several versions of IEEE 802.11 physical (PHY) layer. All versions of IEEE 802.11 use a common

MAC sublayer. When implementing distributed coordination function (DCF) the 802.11 MAC uses carrier

sense multiple access with collision avoidance (CSMA/CA) for medium access control. The scope of this

recommended practice is limited to DCF implementations of IEEE 802.11, and does not include point

coordination function (PCF) implementations. Initially, 802.11 included both a 1- and 2-Mbit/s frequency-

hopping spread spectrum (FHSS) PHY layer, as well as a 1- and 2-Mbit/s direct sequence spread spectrum

(DSSS) PHY layer. The FHSS PHY layer uses a 1-MHz channel separation and hops pseudo-randomly over

79 channels. The DSSS PHY layer uses a 22 MHz channel and may support up to three non-overlapping

channels in the unlicensed band.

Subsequently, the IEEE 802.11 DSSS PHY layer was extended to include both 5.5 and 11 Mbit/s data rates

using complementary code keying (CCK). This high-rate PHY layer is standardized to be named IEEE

IEEE

WITH OTHER WIRELESS DEVICES OPERATING IN UNLICENSED FREQUENCY BANDS Std 802.15.2-2003

802.11b. This high-rate version includes four data rates: 1, 2, 5.5, and 11 Mbit/s. The channel bandwidth of

the IEEE 802.11b PHY layer is 22 MHz.

The WPAN covered in this recommended practice is IEEE Std 802.15.1-2002, which is a 1-Mbit/s FHSS

system. The IEEE 802.15.1 PHY layer uses the same 79, 1 MHz-wide channels that are used by the FHSS

version of IEEE 802.11. IEEE 802.15.1 hops pseudo-randomly at a nominal rate of 1600 hops/second. The

IEEE 802.15.1 MAC sublayer supports a master/slave topology referred to as a piconet. The master controls

medium access by polling the slaves for data and using scheduled periodic transmission for voice packets.

The following is a brief description of the interference problem for each of the three systems: IEEE 802.11

frequency-hopping (FH), IEEE 802.11b, and IEEE 802.15.1.

4.1.1 IEEE 802.11 FH WLAN in the presence of IEEE 802.15.1 interference

The IEEE 802.11 FH WLAN has the same hopping channels as the IEEE 802.15.1 WPAN. However, the

two systems operate at very different hopping rates. IEEE 802.11 FH speciﬁes a hopping rate of greater than

2.5 hops/second, with typical systems operating at 10 hops/second. IEEE 802.15.1 speciﬁes a maximum

hopping rate of 1600 hops/second for data transfer. So while IEEE 802.11 FH dwells on a given frequency

for approximately 100 ms, IEEE 802.15.1 will have hopped 160 times. So the odds are that IEEE 802.15.1

will hop into the frequency used by IEEE 802.11 FH several times while IEEE 802.11 FH is dwelling on a

given channel. IEEE 802.11 FH packets will be corrupted by the IEEE 802.15.1 interference whenever IEEE

802.15.1 hops into the channel used by IEEE 802.11 FH, assuming the IEEE 802.15.1 power level is high

enough to corrupt the IEEE 802.11 FH packet at the IEEE 802.11 FH receiver. It is also possible for the

IEEE 802.11 FH WLAN packet to be corrupted by the IEEE 802.15.1 interference if the IEEE 802.15.1

packet is sent in an adjacent channel to the IEEE 802.11 FH data. For example, if currently IEEE 802.11 FH

is using the 2440 MHz channel then the two adjacent channels are at 2439 and 2441 MHz. Usually, there is

only limited attenuation in adjacent channels. It is likely that there will be limited interference if the IEEE

802.15.1 WPAN is greater than one channel away from the current IEEE 802.11 FH channel. Whether an

IEEE 802.11 packet is corrupted or not depends on how close the IEEE 802.15.1 unit is to the IEEE 802.11

FH unit, because that effects the interference power level.

The IEEE 802.11 MAC sublayer incorporates automatic repeat request (ARQ) to insure reliable delivery of

data across the wireless link. So there is little chance that the data will be lost. The impact of interference on

the WLAN is that the delivered data throughput decreases and the network latency increases. The applica-

tion’s requirements determine if these degradations are tolerable.

4.1.2 IEEE 802.11b WLAN in the presence of IEEE 802.15.1 interference

The high-rate IEEE Std 802.11b-1999 deﬁnes a frequency-static WLAN that supports four data rates: 1, 2,

5.5, and 11 Mbit/s. Most implementations allow manual or automatic modiﬁcation of the data rate. The

higher rates are desirable for many applications but the distance of transmission using the higher rates is less

than that of the lower rates. Many implementations automatically scale the data rate to the highest data rate

that is sustainable to each WLAN mobile unit.

The bandwidth of IEEE 802.11b is up to 22 MHz. There is a potential packet collision between a WLAN

packet and an IEEE 802.15.1 packet when the WPAN hops into the WLAN passband. Since the bandwidth

of the IEEE 802.11b WLAN is 22 MHz, as the IEEE 802.15.1 WPAN hops around the unlicensed band, 22

of the 79 IEEE 802.15.1 channels fall within the WLAN passband.

Because there are four data rates deﬁned within IEEE 802.11b, the temporal duration of the WLAN packets

may vary signiﬁcantly for packets carrying the exact same data. The longer the duration of the WLAN

packet, the more likely that it may collide with an interfering WPAN packet.

IEEE

Std 802.15.2-2003 LOCAL AND METROPOLITAN AREA NETWORKS—PART 15.2: COEXISTENCE OF WPANS

One of the important issues that effects the level of interference is the WLAN automatic data rate scaling. If

it is implemented and enabled, it is possible for the WPAN interference to cause the WLAN to scale to a

lower data rate. At a lower data rate the temporal duration of the WLAN packets is increased. This increase

in packet duration may lead to an increase in packet collisions with the interfering WPAN packets. In some

implementations, this may lead to yet a further decrease in the WLAN data rate. This may result in the

WLAN scaling down its data rate to 1 Mbit/s.

The IEEE 802.11 MAC sublayer incorporates ARQ to insure reliable delivery of data across the wireless

link. So there is little chance that the data will be lost. The effect this has on the WLAN is that the delivered

data throughput decreases and the network latency increases. The application’s requirements determine if

these degradations are tolerable.

4.1.3 IEEE 802.15.1 in the presence of an IEEE 802.11 FH interferer

Both IEEE 802.15.1 and IEEE 802.11 FH use FHSS by using the same 79 channels. Both FH systems are

susceptible to interference on the channel in use and the two adjacent channels. Also, because IEEE 802.15.1

uses short packets the packet error rate (PER) in IEEE 802.15.1 in the presence of IEEE 802.11 FH is not

very signiﬁcant.

IEEE 802.15.1 uses two types of links between the piconet master and the piconet slave. For data transfer

IEEE 802.15.1 uses an asynchronous connectionless (ACL) link. The ACL link incorporates ARQ to ensure

reliable delivery of data. IEEE 802.15.1 voice communications use a synchronous connection-oriented

(SCO) link. On account of the SCO link does not support ARQ, there will be some perceivable degradation

in voice quality during periods of IEEE 802.11 FH interference. The detailed model described later quanti-

ﬁes the level of PER. The network throughput would decrease and the network latency would increase for

IEEE 802.11 FH interference. A large number of errors on a SCO link can cause voice quality degradation.

4.1.4 IEEE 802.15.1 in the presence of an IEEE 802.11b interferer

IEEE 802.15.1 uses FHSS, while IEEE 802.11b uses DSSS and CCK. The bandwidth of IEEE 802.11b is 22

MHz. 22 of the 79 hopping channels available to IEEE 802.15.1 hops are subject to interference. A FH sys-

tem is susceptible to interference from the adjacent channels as well. This increases the total number of

interference channels from 22 to 24. The detailed model, which is described later, quantiﬁes the level of PER

based on these assumptions. The IEEE 802.11b is used because it represents a worse interferer than the

IEEE 802.11 FH. The results from this scenario for data transfers are that the network throughput would

decrease and the network latency would increase, in the presence of IEEE 802.11b interference. The PER for

a SCO link may cause voice quality degradation.

4.2 Overview of the coexistence mechanisms

There are two categories of coexistence mechanisms: collaborative and non-collaborative. Collaborative

coexistence mechanisms exchange information between two wireless networks. That is in this case a collab-

orative coexistence mechanism requires communication between the IEEE 802.11 WLAN and the IEEE

802.15 WPAN. Non-collaborative mechanisms do not exchange information between two wireless net-

works. These coexistence mechanisms are only applicable after a WLAN or WPAN are established and user

data is to be sent. These coexistence mechanisms will not help in the process for establishing a WLAN or

WPAN.

Both types of coexistence mechanisms are designed to mitigate interference resulting from the operation of

IEEE 802.15.1 devices in the presence of frequency static or slow-hopping WLAN devices (for example

IEEE 802.11b). Note that interference due to multiple IEEE 802.15.1 devices is mitigated by frequency-hop-

ping. All collaborative coexistence mechanism described in this recommended practice are intended to be

used when at least one WLAN station and WPAN device are collocated within the same physical unit.

IEEE

WITH OTHER WIRELESS DEVICES OPERATING IN UNLICENSED FREQUENCY BANDS Std 802.15.2-2003

When collocated, there needs to be a communication link between the WLAN and WPAN devices within

this physical unit, which could be a wired connection between these devices or an integrated solution. The

exact implementation of this communication link is outside the scope of this recommended practice.

Non-collaborative coexistence mechanisms are intended to be used when there is no communication link

between the WLAN and WPAN.

Table 1 shows the coexistence mechanisms listed in this recommend practice. The “Name” column assigns

the name of the coexistence mechanism. The “Type” column lists whether it is collaborative or non-collabo-

rative. The “Clause/Annex” column gives the location within this recommended practice where the descrip-

tion of this mechanism may be found.

4.2.1 Collaborative coexistence mechanisms

The three collaborative coexistence mechanisms deﬁned in this recommended practice consist of two MAC

sublayer techniques (see Clause 5 and Clause 6) and one PHY layer technique (see Clause 7). Both MAC

sublayer techniques involve coordinated scheduling of packet transmission between the two wireless

(WLAN and WPAN) networks. The PHY layer technique is a programmable notch ﬁlter in the IEEE

802.11b receiver to notch out the narrow-band IEEE 802.15.1 interferer. These collaborative mechanisms

may be used separately or combined with others to provide a better coexistence mechanism.

The collaborative coexistence mechanism provides coexistence of a WLAN (in particular IEEE 802.11b)

and a WPAN (in particular IEEE 802.15.1

) by sharing information between collocated IEEE 802.11b and

IEEE 802.15.1 radios and locally controlling transmissions to avoid interference. These mechanisms are

interoperable with legacy devices that do not include these features.

There are two modes of operation and the mode is chosen depending on the network topology and supported

trafﬁc. In the ﬁrst mode, both IEEE 802.15.1 SCO and ACL trafﬁc are supported where SCO trafﬁc is given

higher priority than the ACL trafﬁc in scheduling. The second mode is based on time-division multiple

Table 1—Listing of the coexistence mechanisms

Name Type Clause/Annex

Alternating wireless medium access collaborative Clause 5

Packet trafﬁc arbitration collaborative Clause 6

Deterministic interference suppression collaborative Clause 7

Adaptive interference suppression non-collaborative Clause 8

Adaptive packet selection non-collaborative Clause 9

Packet scheduling for ACL links non-collaborative Clause 10

Packet scheduling for SCO links non-collaborative Annex A

Adaptive frequency-hopping non-collaborative Annex B

Although this recommended practice consistently references IEEE 802.15.1, and not Bluetooth®, the mechanism is equally applica-

ble to both IEEE 802.15.1 and Bluetooth®.

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无线个人区域网与其它无线设备共存实践

802.15标准合集

802.15.2-coexistence of wpan with wlan in 2.4G band

802.15.4-2015.pdf

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