WO2016175684A1

WO2016175684A1 - Method for providing transmission and/or reception time coordination between piconets

Info

Publication number: WO2016175684A1
Application number: PCT/SE2015/050469
Authority: WO
Inventors: Leif Wilhelmsson; Bo Hagerman; Per Skillermark; Pontus ARVIDSON; Yi-Pin Eric Wang
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2015-04-27
Filing date: 2015-04-27
Publication date: 2016-11-03

Abstract

A First Primary Device (FPD) 612, and a method therein, for providing transmission and/or reception time coordination during concurrent operation with a Second Primary Device (SPD) 622. The FPD 612 and SPD 622 are collocated and arranged in communication with a First Secondary Device (FSD) 614 and a Second Secondary Device (SSD) 624, respectively. The FPD 612 and the FSD 614 are operating in a first piconet 610 using a first communication mode. The SPD 622 and the SSD 624 are operating in a second piconet 620. The method comprises receiving, from the SPD 622, information relating to a length of a data packet to be transmitted from or that is received by the SPD 622; and transmitting a FPD data packet to the FSD 614 in accordance with the received information, whereby transmission and/or reception time coordination during concurrent operation of the FPD 612 and the SPD 622 is provided.

Description

METHOD FOR PROVIDING TRANSMISSION AND/OR RECEPTION TIME COORDINATION BETWEEN PICONETS

TECHNICAL FIELD

Embodiments herein relate generally to a First Primary Device (FPD), a First

Secondary Device (FSD), and to methods therein. In particular, they relate to providing transmission and/or reception time coordination during concurrent operation with a second primary device. BACKGROUND

Communication devices such as terminals are also known as e.g. User

Equipments (UE), mobile terminals, wireless devices, wireless terminals and/or mobile stations. Terminals are enabled to communicate wirelessly in a wireless communications network such as a Wireless Local Area Network (WLAN), or a cellular communications network, sometimes also referred to as a cellular radio system or cellular networks. The communication may be performed e.g. between two terminals, between a terminal and a regular telephone and/or between a terminal and a server via a Radio Access Network (RAN) and possibly one or more core networks, comprised within the wireless

communications network.

Terminals may further be referred to as mobile telephones, cellular telephones, laptops, or tablets with wireless capability, just to mention some further examples. The terminals in the present context may be, for example, portable, pocket-storable, handheld, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the RAN, with another entity, such as another terminal or a server.

The cellular communications network covers a geographical area which is divided into cell areas, wherein each cell area being served by an access node such as a base station, e.g. a Radio Base Station (RBS), which sometimes may be referred to as e.g. "eNB", "eNodeB", "NodeB", "B node", or BTS (Base Transceiver Station), depending on the technology and terminology used. The base stations may be of different classes such as e.g. macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size. A cell is the geographical area where radio coverage is provided by the base station at a base station site. One base station, situated on the base station site, may serve one or several cells. Further, each base station may support one or several communication technologies. The base stations communicate over the air interface operating on radio frequencies with the terminals within range of the base stations. In the context of this disclosure, the expression Downlink (DL) is used for the transmission path from the base station to the mobile station. The expression Uplink (UL) is used for the transmission path in the opposite direction i.e., from the mobile station to the base station.

In 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), base stations, which may be referred to as eNodeBs or even eNBs, may be directly connected to one or more core networks.

3GPP LTE radio access standard has been written in order to support high bitrates and low latency both for uplink and downlink traffic. All data transmission is in LTE controlled by the radio base station.

With a vision of 50 billion connected devices by the year 2020, a very large fraction of these connections will be between a sensor and a gateway. For example, the sensor may be a temperature sensor, a humidity sensor, a velocity sensor, etc. configured to register data such as temperature, humidity, velocity, etc., which typically comprises very little data that needs to be transmitted relatively seldom and at irregular intervals. The gateway may for instance be a mobile phone, a laptop, or a fixed mounted Access Point (AP). The backhaul for the gateway may either be a wireless communications network e.g. a cellular communications network based on 3GPP technologies, such as LTE or WCDMA, or it could be a wired communications network.

The description herein is based on the assumption that the transmissions largely follow the principles used in a Bluetooth Low Energy (BLE) transmission. Following the terminology in BLE, it is assumed that the network topology comprises a master device and one or more slave devices. The master device and the one or more slave devices are herein sometimes referred to as just master and slaves, respectively. When master and slave devices are connected, they are said to belong to the same piconet. By the term piconet when used herein is meant a network which links a number of wireless devices using a wireless communication technology protocol such as Bluetooth wireless technology protocols. The piconet may comprise two or more wireless devices occupying the same physical channel, e.g. the two or more devices may be synchronized to a common clock and hopping sequence. The piconet allows one master device to interconnect with a number of slave devices. Up to for example 255 slave devices may be inactive, or parked in the piconet, and the master device may bring one or more of the inactive or parked devices into active status at any time. Some examples of a piconet comprise a communication device, such as a mobile phone, connected to a computer, a laptop, a Bluetooth-enabled digital camera, and/or comprise several Personal Digital Assistants (PDAs) that are connected to each other.

Figure 1 schematically illustrates a piconet comprising one master device denoted Master and two slave devices denoted Slavel and Slave2, respectively.

The transmission in a BLE communication is based on Time Division Duplexing (TDD), i.e., the master device is alternating between transmitting to and receiving from the different slave devices. The switching time from transmission to reception is referred to as an Inter Frame Space (IFS), and is sometimes denoted T_IFS. In BLE the T_IFS is fixed to 150 microseconds (με). Figure 2 schematically illustrates the transmissions between the master device and the slave devices. As schematically illustrated, the master device Master is first transmitting a packet M1 during a period of time t_M 1 to the slave device Slavel . After a period of time longer or equal to the IFS T_IFS the slave device Slavel transmits a packet S1 during a period of time t_S1 back to the master device Master. After yet another period of time T_IFS, the master device Master transmits a packet M2 during a period of time t_M2 to the slave device Slave2, and after another period of time T_IFS the slave device Slave2 transmits a packet S2 during a period of time t_S2 back to the master device Master, and so on.

Since the symbol rate used in BLE is 1 Msymbol/s, it means that the number of slave devices which may be supported is rather limited unless the activity in the piconet is small. As previously mentioned, it is envisioned that the number of connected devices, e.g. sensors, will increase drastically. Therefore, it is envisioned to be a problem also if the average data rate for a slave device is very small, say only a hundred bytes per hour. The problem may be expected to be even further pronounced with the introduction of a long range mode for BLE, herein sometimes referred to as Bluetooth Long Range (BLR). With a significantly longer range, the number of slave devices within coverage for a master device may easily be several thousand.

Now, since BLE is operating in the unlicensed 2.4 GHz Industrial Science and

Medical (ISM) radio band, there is about 80 MHz spectrum available. BLE uses frequency hopping, which means that it is rather robust against interference and also that several piconets may be partially overlapping and only marginally degrade the performance for one another. Typically, a transmission within one piconet will only cause problem for a transmission in another piconet if both piconets happen to use the same channel or possibly adjacent channels. In case the interference is further apart, it is typically sufficiently suppressed by the Channel Selective Filter (CSF), which has a bandwidth of approximately 1 MHz.

The reason why only co-channel interference or interference from the first adjacent channel will cause problem for a link is that the Signal-to-lnterference Ratio (SIR), or Carrier-to-interference (C/l) that may be handled are significantly smaller when the interferer is further away from the desired signal. According to the required interference performance in the BLE specification it is stated that C/l = 21 dB for co-channel interference, C/l = 15 dB for adjacent (1 MHz) interference, C/l = -17 dB for adjacent (2MHz) interference, and C/l = -27 dB for adjacent (> 2 MHz) interference. To appreciate the difference these numbers make, consider a simple model for the distance dependent pathloss given by PL(d) = 40 + 30 · Iog10(d), wherein d is the distance in meters and the PL(d) is the pathloss in dB.

Figure 3 schematically illustrates pathloss versus distance between a transmitter and a receiver. It should be understood that the transmitter may be the master device and the receiver may be the slave device, or vice versa. Suppose that the desired signal and the interfering signal are transmitted with the same power, and that a reasonable estimation of the C/l may be obtained by comparing the distance dependent pathloss for the desired signal and the interfering signal, respectively. In practice there is also frequency selective fading which means that some of the channels within the ISM band may be received at significantly lower power, but for the ease of this description it is omitted herein. Moreover, suppose that the distance between the transmitter and the receiver for the desired signal is about 50 meters. Then, as illustrated in Figure 3, the distance of 50 meters corresponds to a path loss of 90 dB. For a co-channel interferer, the C/l needs to be 21 dB, which corresponds to that the pathloss for the interference needs to be 90+21 = 1 11 dB. Referring again to Figure 3, this implies that the interferer, i.e. the transmitter, needs to be more than 200 meters away from the receiver of the desired signal.

If instead the interfering signal would be using a channel 2 MHz away, it would suffice that the interferer is about 10 meters from the receiver of the desired signal not to cause any degradation. Therefore, if it may be assumed that the interferers would be distributed evenly throughout the area, there would be about (200/10)^Λ2 = 400 times more potential co-channel interferers.

In case the interferer would be more than 2 MHz away, it may very well be so that it may be as close as 1 meter without degrading the performance as many products on the market have significantly better C/l performance than required by the specification, especially when the frequency separation between the desired signal and the interfering signal is, say, 5MHz or more.

The discussion above has essentially been assuming that the interferer is in another device, which potentially may be rather close, say, 1 meter. However, a much more challenging situation appears in case the interferer would actually be collocated within the same device. If this would be the case, the received power from the interferer may easily be 80-100 dB stronger than the received power from the desired signal. To handle such large difference in signal power is rather challenging, especially if the solution needs to be implemented in a cost efficient way. When the interfering device, e.g. the transmitter, is collocated with the victim, all channels within the band rather than just the closest ones are typically severely degraded due to saturation effects in the front-end of the receiver.

It is often referred to as In-Device Coexistence (IDC) when two or more systems that are potentially interfering with one another are located within the same device, or even within the same chip. When filtering is found unfeasible for IDC, one has to resort to Time Division Multiplexing (TDM). That is, the two or more systems cannot work independently of one another but has to properly adjust their timing for transmission and reception.

An example of TDM for solving coexistence issues in the ISM band is when

Bluetooth and WLAN are collocated in a device, e.g. in a communication device. If WLAN is also using the 2.4 GHz ISM band, Bluetooth and WLAN cannot operate at the same time. Therefore, when Bluetooth and WLAN are collocated coexistence is ensured by means of Packet Traffic Arbitration (PTA), as e.g. disclosed in IEEE 802.15.2.

In its simplest form of TDM, only one standard at a time may be active. However, typically the problem with concurrent operation is only present when one of the systems is transmitting while the other system is receiving. That is, when two systems are transmitting at the same time or receiving at the same time, both systems are typically working properly. Therefore, if it is possible to align the operation of the different transceivers, two or more transceivers may operate in close vicinity. This kind of alignment is possible if all the involved systems use a fixed Time Division Duplex (TDD) frame structure, as then it is known long in advance when a system may be transmitting or when the system potentially may be receiving.

For systems like WLAN or BLE, no such fixed TDD structure exists. Instead, as in BLE, there is a predetermined time between reception and transmission, which means that the start of the transmission is dependent on the length of the received packet, which in turn may be highly variable.

Figure 4 schematically shows an example with two collocated BLE master devices Masterl and Master2, respectively. By the term collocated is meant that the two master devices Masterl and Master2 are arranged in or at a common device, e.g. a single device, such as a communications device. As further illustrated in Figure 4, the two master devices Masterl and Master2 are connected to a respective slave device Slavel and Slave2. An illustration of a packet exchange using a fixed IFS is schematically illustrated in Figure 5. Referring to Figure 5, the master devices Masterl and Master2 both start to transmit at the same time, and the two packets M 1 and M2 are both received successfully at the slave devices Slavel and Slave2, respectively. Then, the slave devices Slavel and Slave2 respond to their respective master device. The packet S1 from slave device Slavel is successfully received by master device Masterl The packet S2 from slave device Slave2 is longer than the packet S1. For this reason packet S2 will be severely interfered at the end of the packet as the master device Masterl will start to transmit a new packet M1 a period of time T_IFS after its reception of the packet S1. This is schematically illustrated in Figure 5 with the arrow from the slave device Slave2 to the master device Master2 being crossed out. The master device Master2 knows the duration of packet S2, since it is here assumed that the first part of S2 comprises that information and is correctly received, and then sends a new packet M2 including a negative acknowledgement (NACK) of the packet from the slave device Slave2. Now, the transmission from the master device Master2 will interfere with the packet S1 sent from Slavel . This is schematically illustrated in Figure 5 with the arrow from the slave device Slavel to the master device Masterl being crossed out. The transmission from the slave device Slavel will however not cause a problem for the slave device Slave2, as these two slave devices are assumed to be sufficiently far apart. The packet M2 from the master device Master2 is thus acknowledged by the slave device Slave2 and the previous data packet S2 from the slave device Slave2 to the master device Master2 is retransmitted. However, this will now be corrupted due to the transmission from the master device Masterl . This is schematically illustrated in Figure 5 with the arrow from the slave device Slave2 to the master device Master2 being crossed out.

As explained above, a drawback with wireless systems that uses a fixed IFS is that they under typical conditions, severely interfere with each other if more than one master device is active within a single device such as a communications device, whereby the performance in the wireless communications network is deteriorated. SUMMARY

Therefore, an object of embodiments herein is to provide a way of improving the performance in a wireless communications network, e.g. in a piconet.

According to a first aspect of embodiments herein, the object is achieved by a method in a first primary device for providing transmission and/or reception time coordination during concurrent operation with a second primary device. The first and second primary devices are collocated and arranged in communication with a first secondary device and a second secondary device, respectively. The first primary device and the first secondary device are operating in a first piconet using a first communication mode based on Time Division Duplexing (TDD) using an Inter Frame Space (IFS), and the second primary device and the second secondary device are operating in a second piconet.

The first primary device receives information from the second primary device which information relates to a length of a data packet to be transmitted from or that is received by the second primary device.

Further, the first primary device transmits a first primary device data packet to the first secondary device in accordance with the received information. Thereby, transmission and/or reception time coordination during concurrent operation of the first primary device and the second primary device is provided.

According to a second aspect of embodiments herein, the object is achieved by a first primary device for providing transmission and/or reception time coordination during concurrent operation with a second primary device. The first and second primary devices are collocated and arranged in communication with a first secondary device and a second secondary device, respectively. The first primary device and the first secondary device are operating in a first piconet using a first communication mode based on Time Division Duplexing (TDD) using an Inter Frame Space (IFS). The second primary device and the second secondary device are operating in a second piconet.

The first primary device is configured to receive information from the second primary device which information relates to a length of a data packet to be transmitted from or that is received by the second primary device. Further, the first primary device is configured to transmit a first primary device data packet to the first secondary device in accordance with the received information. Thereby, transmission and/or reception time coordination during concurrent operation of the first primary device and the second primary device is provided.

According to a third aspect of embodiments herein, the object is achieved by a method in a first secondary device for providing transmission and/or reception time coordination during concurrent operation of a first primary device and a second primary device. The first and second primary devices are collocated and arranged in

communication with the first secondary device and a second secondary device, respectively. The first primary device and the first secondary device are operating in a first piconet using a first communication mode based on Time Division Duplexing (TDD) using an Inter Frame Space (IFS). The second primary device and the second secondary device are operating in a second piconet.

The first secondary device receives a first primary device data packet from the first primary device, which first primary device data packet comprises information relating to a length of a data packet to be transmitted from or that is received by the second primary device.

Further, the first secondary device transmits a first secondary device data packet to the first primary device in accordance with the information comprised in the first primary device data packet. Thereby, transmission and/or reception time coordination during concurrent operation of the first primary device and the second primary device is provided. According to a fourth aspect of embodiments herein, the object is achieved by a first secondary device for providing transmission and/or reception time coordination during concurrent operation of a first primary device and a second primary device. The first and second primary devices are collocated and arranged in communication with the first secondary device and a second secondary device, respectively. The first primary device and the first secondary device are operating in a first piconet using a first communication mode based on Time Division Duplexing (TDD) using an Inter Frame Space (IFS). The second primary device and the second secondary device are operating in a second piconet.

The first secondary device is configured to receive a first primary device data packet from the first primary device, which first primary device data packet comprises information relating to a length of a data packet to be transmitted from or received by the second primary device.

Further, the first secondary device is configured to transmit a first secondary device data packet to the first primary device in accordance with the information comprised in the first primary device data packet. Thereby, transmission and/or reception time coordination during concurrent operation of the first primary device and the second primary device is provided.

According to a fifth aspect of embodiments herein, the object is achieved by a computer program, comprising instructions which, when executed on at least one processor, causes the at least one processor to carry out the method in the first primary device.

According to a sixth aspect of embodiments herein, the object is achieved by a computer program, comprising instructions which, when executed on at least one processor, causes the at least one processor to carry out the method in the first secondary device.

According to a seventh aspect of embodiments herein, the object is achieved by a carrier comprising the computer program, wherein the carrier is one of an electronic signal, optical signal, radio signal or computer readable storage medium.

Since the first primary device receives information from the second primary device which information relates to a length of a data packet to be transmitted from or received by the second primary device, and since the first primary device transmits a first primary device data packet to the first secondary device in accordance with the received information, the transmission and/or reception time coordination during concurrent operation of the first primary device and the second primary device is provided. Thereby, problems with interference, the loss of data packets and/or the need of retransmitting data packets is avoided or reduced. This results in an improved performance in the wireless communications network.

An advantage by embodiments herein is that they largely increase the number of slave devices that may be effectively supported by a first primary device collocated with a second primary device in or at a communications device. This effectively means that the same area, e.g. the same coverage area, and the same number of communications devices may be supported by a reduced number of network nodes, e.g. APs and/or base stations as each network node may comprise more than one primary device, e.g. a first primary device and a second primary device, each with its own piconet. This, in turn, implies that the installation cost as well as the cost for maintenance is reduced.

BRIEF DESCRIPTION OF DRAWINGS

Examples of embodiments herein are described in more detail with reference to attached drawings in which:

Figure 1 schematically illustrates a piconet comprising one master device and two slave devices;

Figure 2 schematically illustrates exemplifying transmissions between the master device and the slave devices comprised in the piconet of Figure 1 ;

Figure 3 schematically illustrates pathloss versus distance;

Figure 4 schematically illustrates a piconet comprising two collocated BLE master devices connected to a respective slave device;

Figure 5 schematically illustrates exemplifying transmissions between the collocated master devices and the slave devices comprised in the piconet of Figure 4;

Figure 6 schematically illustrates embodiments of a communications network;

Figure 7 is a flowchart depicting embodiments of a method in a First Primary Device (FPD);

Figure 8 is a schematic block diagram illustrating embodiments of a First Primary Device (FPD);

Figure 9 is a flowchart depicting embodiments of a method in a First Secondary Device (FSD);

Figure 10 is a schematic block diagram illustrating embodiments of a First Secondary Device (FSD);

Figure 11 schematically illustrates first exemplifying transmissions in embodiments of a communication network;

Figure 12 schematically illustrates second exemplifying transmissions in embodiments of a communication network;

Figure 13 schematically illustrates third exemplifying transmissions in embodiments of a communication network; and Figure 14 schematically illustrates fourth exemplifying transmissions in embodiments of a communication network.

DETAILED DESCRIPTION

As part of developing embodiments herein, some problems will first be identified and discussed.

As previously mentioned, wireless systems that use a fixed IFS rather than a fixed frame structure will under typical conditions severely interfere with one another if more than one unit, e.g. more than one master device, is active within the same device, e.g. the same communications device. The situation with more than one master device in the same device, e.g. the same communications device, is expected to be emerging with an increased number of sensor devices, e.g. slave devices, and thus the present standards, like BLE, are not suitable for this kind of installation.

Therefore, according to embodiments herein, a way of improving the performance in a wireless communications network is provided by transmission and/or reception time coordination during concurrent operation of two master devices, herein referred to as a first primary device and a second primary device. The first and second primary devices are collocated and arranged in communication with a respective slave device, herein referred to as a first secondary device and a second secondary device, respectively. The first primary device and the first secondary device are operating in a first piconet using a first communication mode based on TDD using an IFS. The second primary device and the second secondary device are operating in a second piconet.

Embodiments herein are based on effective means to avoid that a node comprising more than one collocated device, e.g. the first primary device and the second primary device, has to both transmit and receive simultaneously, still allowing concurrent transmission or reception to multiple devices, such as slave devices and collocated master devices, to enhance spectrum efficiency.

It should be understood that even if embodiments herein are described with reference to two collocated primary devices, e.g. the first and second primary device, more than two primary devices may be collocated within a node, e.g. a single node, such as a communications device. Below, embodiments herein will be illustrated in more detail by a number of exemplary embodiments. It should be noted that these embodiments are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments.

Figure 6 schematically illustrates a communications network 600 in which embodiments herein may be implemented. The communications network 600 may be or may comprise a wireless communications network such as a Wireless Local Area

Network (WLAN), a wireless network using Bluetooth wireless technology such as BLE or BLR, and/or a cellular communications network.

The WLAN may be any wireless computer network that by means of a wireless distribution method links two or more devices within a limited area such as a home, a school, a shopping mall, a coffee shop, a computer laboratory, or an office building. The wireless distribution method may be a spread-spectrum method or an Orthogonal Frequency-Division Multiplexing (OFDM) radio method. For example, the WLAN may be implemented according to the IEEE 802.11 standard. The IEEE 802.1 1 standard comprises a set of Media Access Control (MAC) and PHYsical layer (PHY) specifications for implementing WLAN computer communication in the 2.4, 3.6, 5 and 60 GHz frequency bands.

The cellular communications network or sub-networks may be a LTE network, any other 3GPP cellular network, WMAX, or any other cellular network or system. The communications network 600 comprises a first sub-network having a first coverage area, e.g. a first Radio Frequency (RF) coverage area, and a second subnetwork having a second coverage area, e.g. a second RF coverage area. The first and second sub-networks may for example be a first piconet 610 and a second piconet 620. Further, the first and second sub-networks may be overlapping sub-networks, i.e. the first and second coverage areas may be overlapping as schematically illustrated in Figure 6.

A first master device, e.g. a First Primary Device (FPD) 612 operates in the communications network 600. Further, the First Primary Device 612 may be located in the communications network 600. Furthermore, the First Primary device 612 is configured to operate in the first sub-network having the first coverage area. A second master device, e.g. a Second Primary Device (SPD) 622 operates in the communications network 600. Further, the Second Primary Device 622 may be located in the communications network 600. Furthermore, the Second Primary device 622 is configured to operate in the second sub-network having the second coverage area. 5 The first primary device 612 and the second primary device 622 are collocated, i.e. they are arranged within a predefined area. For example, the first primary device 612 and the second primary device 622 may be collocated within or at the same communications device (not shown). The first primary device 612 and the second primary device 622 may be a WLAN device or a BLE device.

10 The communications device may be a wireless device such as a User Equipment

(UE), a mobile terminal or a wireless terminal, a mobile phone, a computer such as e.g. a laptop, a Personal Digital Assistant (PDA) or a tablet computer, with wireless capability, or any other radio network units capable to communicate over a communication link, e.g. a radio link, in the communications network 600. Please note that the term user equipment

15 used in this document also covers other wireless devices such as Machine to Machine (M2M) devices, even though they do not have any user.

A first slave device, e.g. a First Secondary Device (FSD) 614 operates in the communications network 600. Further, the first Secondary Device 614 may be located in the communications network 600. Furthermore, the First Secondary device 614 is

20 configured to operate with the first primary device 612 in the first sub-network having the first coverage area.

A second slave device, e.g. a Second Secondary Device (SSD) 624 operates in the communications network 600. Further, the Second Secondary Device 624 may be located in the communications network 600. Furthermore, the Second Secondary device 25 624 is configured to operate with the second primary device 622 in the second subnetwork having the second coverage area. The first secondary device 614 and the second secondary device 624 may be sensors, such as temperature sensors, humidity sensors, velocity sensors, etc.

A method performed in embodiments of the first primary device 612 for providing transmission and/or reception time coordination during concurrent operation with the second primary device 622 will now be described with reference to Figure 7. Reference will sometimes also be made to Figures 11 -14 which schematically illustrate some exemplifying transmissions in embodiments of a communication network. However, the Figures 1 1-14 will be described in more detailed in the section relating to exemplifying embodiments, As mentioned above, the first primary device 612 and the second primary device 622 are collocated and arranged in communication with the first secondary device 614 and the second secondary device 624, respectively. Further, the first primary device 5 612 and the first secondary device 614 are operating in the first piconet 610 using a first communication mode based on TDD using an IFS. In some embodiments, the first communication mode is based on TDD using a variable IFS. Furthermore, the second primary device 622 and the second secondary device 624 are operating in the second piconet 620. In some embodiments, the second primary device 622 and the second

10 secondary device 624 are operating using the first communication mode. However, it should be understood that the second primary device 622 and the second secondary device 624 may be legacy devices operating using a communication mode, e.g. a legacy communication mode, different from the first communication mode. Thereby coexistence, e.g. transmission and/or reception time coordination during concurrent operation with the

15 second primary device 622, is ensured by the first primary device 612 on its own. The legacy communication mode may for example be an old BLE device not capable of varying the IFS.

The method comprises one or more of the following actions. It should be understood that some actions are optional, that actions may be taken in another suitable

20 order and that actions may be combined. In the description below, a general embodiment comprises Actions 701 and 708, but reference will also be made to some first

embodiments comprising Actions 701 , 702 and 708; some second embodiments comprising Actions 701 , 703, and 708; some third and fourth embodiments comprising Actions 701 , 704, 705 and 708; some fifth embodiments comprising Actions 701 , 706 and

25 708; and some sixth embodiments comprising Actions 701 , 707 and 708. However, it should be understood that even if embodiments herein are described below with reference to some first, second, third, fourth, fifth and sixth embodiments, two or more of these embodiments may be combined in a suitable way. Further, some of the described embodiments relate to both the first primary device's 612 direct and indirect control of the

30 transmission and/or reception time coordination. By direct control of the transmission and/or reception time coordination is meant that the first primary device adjusts and/or adapts a data packet it is to transmit or the transmission thereof in order to obtain transmission and/or reception time coordination. By indirect control of the transmission and/or reception time coordination is meant that the first primary device controls the first

35 secondary device to adjust and/or adapt a data packet it is to transmit or the transmission thereof in order to obtain the transmission and/or reception time coordination. Sometimes herein the expressions "direct control" and "indirect control" will be used. Further, the direct control may be seen as the adjustment and/or adaptation of the data packet at the first primary device side, while the indirect control may be seen as the adjustment and/or 5 adaptation of the data packet at the first secondary device side.

Action 701

In order to obtain information about a data packet M2 to be transmitted from or a data packet S2 that is received at the second primary device 622, the first primary device 10 612 receives information from the second primary device 622 which information relates to a length of the data packet M2,S2 to be transmitted from or received by the second primary device 622.

In some first embodiments, the received information comprises information about the length of a second secondary device data packet S2 transmitted from the second

15 secondary device 624 to the second primary device 622, cf. e.g. Figure 11. In Action 702 below it will be described how this information may be used.

In some second, third and fourth embodiments, the received information comprises information about the length of a second primary device data packet M2 to be transmitted from the second primary device 622 to the second secondary device 624, cf.

20 e.g. Figures 12 and 13. In Action 703 below it will be described how this information may be used in some second embodiments. Further, in Action 704 below it will be described how this information may be used in some third and fourth embodiments.

In some fifth embodiments, the received information comprises information about an agreed data packet length, cf. e.g. Figure 14.

25 In some sixth embodiments, the received information comprises information about the length of a data packet to be transmitted or that is received by the second primary device 622.

Action 702

30 In some of the first embodiments, when the received information comprises

information about the length of the second secondary device data packet S2 transmitted from the second secondary device 624 to the second primary device 622, the first primary device 612 determines an IFS value based on the length of the second secondary device data packet S2. As will be described in Action 708 below, the determined IFS value may

35 be used to delay the transmission of the first primary device data packet M1 which data packet M1 is to be transmitted from the first primary device 612 to the first secondary device 614. This is schematically illustrated in Figure 11 which will be described in more detailed below. Action 703

In some of the second embodiments, when the received information comprises information about the length of a second primary device data packet M2 to be transmitted from the second primary device 622 to the second secondary device 624, the first primary device 612 determines, based on the received information, whether the first secondary device 614 needs to delay its transmission of a first secondary device data packet S1 to the first primary device 612. This is schematically illustrated in Figure 12 which will be described in more detailed below.

Action 704

In some of the third and fourth embodiments relating to direct control, the received information comprises information about the length of the second primary device data packet M2 to be transmitted from the second primary device 622 to the second secondary device 624. In such embodiments, the first primary device 612 determines, based on the received information, whether the second primary device data packet M2 has a length that is longer than the length of the first primary device data packet M1 to be transmitted from the first primary device 612 to the first secondary device 614. As will be described in Action 705 below, the length of the first primary device data packet M1 may then be adjusted. This is schematically illustrated in Figure 13 which will be described in more detailed below.

Action 705

In some of the third and fourth embodiments relating to direct control and when the length of the second primary device data packet M2 has been determined in Action 704 above to be longer than the length of the first primary device data packet M1 , the first primary device 612 adjusts the length of the first primary device data packet M1 in dependence of the received information.

In some of the third embodiments, the first primary device 612 adjusts the length of the first primary device data packet M 1 in dependence of the received information by adjusting the length of the first primary device data packet M1 to become equal or almost equal to the length of the second primary device packet M2 by means of zero-padding. In some of the fourth embodiments, the first primary device 612 adjusts the length of the first primary device data packet M 1 in dependence of the received information by selecting a Modulation and Coding Scheme (MCS) that adjusts the length of the first primary device data packet M1 to become equal or almost equal to the length of the 5 second primary device packet M2. By the expression "equal or almost equal" when used herein is meant that the length of the primary device data packet M1 and the second primary device packet M2 should be sufficient similar to avoid that one of the first primary device 612 and the second primary device 622 is receiving while the other is transmitting.

10 Action 706

In some of the third and fourth embodiments relating to indirect control, the received information comprises information about the length of the second secondary device data packet S2 transmitted from the second secondary device 624 to the second primary device 622. In such embodiments, the first primary device 612 determines, based

15 on the received information, whether the second secondary device data packet S2 has a length that is longer than a length of the first secondary device data packet S1 transmitted from the first secondary device 614 to the first primary device 612.

Thus, as will be described in Action 708, in such embodiments comprising indirect control, the first primary device 612 may instruct the first secondary device 614 to adjust

20 the length of the first secondary device data packet S1 to become equal or almost equal to the length of the second secondary device data packet S2. This is schematically illustrated in Figure 13 which will be described in more detailed below.

Action 707

25 In some of the sixth embodiments, the first primary device 612 determines, based on the received information, that a second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration.

30 Action 708

The first primary device 612 transmits a first primary device data packet M1 to the first secondary device 614 in accordance with the received information, i.e. in accordance with the received information described in Action 701 above. Thereby, transmission and/or reception time coordination during concurrent operation of the first primary device 35 612 and the second primary device 622 is provided. As will be described with reference to the first to sixth embodiments below, by the expression that the first primary device 612 transmits a first primary device data packet M1 to the first secondary device 614 in accordance with the received information is meant that the first primary device 612 adjusts and/or adapts a transmission of the first primary device data packet M 1 based on the received information.

As previously mentioned, in some of the first embodiments, the received information comprises information about the length of the second secondary device data packet S2 transmitted from the second secondary device 624 to the second primary device 622. In such first embodiments relating to direct control and in order to transmit the first primary device data packet M1 in accordance with the received information, the first primary device 612 delays the transmission of the first primary device data packet M 1 until the second primary device 614 has received the second secondary device data packet S2, when the second secondary device data packet S2 has a length that is longer than the length of the first secondary device data packet S1 transmitted from the first secondary device 614 to the first primary device 612. In some embodiments, the first primary device 612 delays the transmission of the first primary device data packet M1 by the IFS value determined in Action 702 above.

As mentioned above, in some of the second embodiments, the received information comprises information about the length of the second primary device data packet M2 to be transmitted from the second primary device 622 to the second secondary device 624. In such second embodiments and in order to transmit the first primary device data packet M 1 in accordance with the received information, the first primary device 612 transmits to the first secondary device 614 the first primary device data packet M 1 comprising information relating to the needed transmission delay. This may be seen as the first primary device 612 instructs the first secondary device 614 to delay its

transmission, and thus it relates to indirect control. In some embodiments, the needed transmission delay is determined in Action 703 above.

As mentioned previously, in some of the third and fourth embodiments relating to direct control, the received information comprises information about the length of the second primary device data packet M2 to be transmitted from the second primary device 622 to the second secondary device 624. Such third and fourth embodiments relates to direct control and in order to transmit the first primary device data packet M1 in

accordance with the received information, the first primary device 612 transmits the adjusted first primary device data packet M 1 to the first secondary device 614. In some embodiments, the adjusted first primary device data packet M2 is adjusted as described in Action 705 above.

As mentioned above, in some of the third and fourth embodiments relating to indirect control, the received information comprises information about the length of the second secondary device data packet S2 transmitted from the second secondary device 624 to the second primary device 622. Such third and fourth embodiments relate to indirect control and in order to transmit the first primary device data packet M1 in accordance with the received information, the first primary device 612 transmits to the first secondary device 614 the first primary device data packet M 1 comprising information instructing the first secondary device 614 to adjust the length of the first secondary device data packet S1 , when the length of the second secondary device data packet S2 is longer than the length of the first secondary device data packet S1.

As previously mentioned, in some of the fifth embodiments which may relate to both direct control and indirect control, the received information comprises information about an agreed data packet length.

In such embodiments relating to direct control and in order to transmit the first primary device data packet M1 in accordance with the received information, the first primary device 612, when a first sub-packet M11 comprised in the first primary device data packet M1 is determined to relate to a voice packet based on a comparison with the agreed data packet length, transmits a first sub-packet M1 1 on a first logical link corresponding to a voice connection, and transmits a second sub-packet M12 comprised in the first primary device data packet M1 on a second logical link corresponding to a data connection. This is schematically illustrated in Figure 14 which will be described in more detail below.

In some of the fifth embodiments relating to indirect control and in order to transmit the first primary device data packet M1 in accordance with the received information, the first primary device 612 transmits to the first secondary device 614 the first primary device data packet M1 comprising information relating to the agreed data packet length.

In some of the sixth embodiments relating to direct control, and in order to transmit the first primary device data packet M1 in accordance with the received information, the first primary device 612 transmits the first primary device data packet M1 during the fixed time slot duration using the second communication mode determined in Action 706 above. In some embodiments and in order to transmit the first primary device data packet M1 in accordance with the received information, the first primary device 612 transmits to the first secondary device 614 the first primary device data packet M 1 comprising information instructing the first secondary device 714 that a second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with the fixed time slot duration.

To perform the method for providing transmission and/or reception time coordination during concurrent operation with the second primary device 622, the first primary device 612 may comprise an arrangement depicted in Figure 8. As previously mentioned, the first primary device 612 and the second primary device 622 are collocated and arranged in communication with the first secondary device 614 and the second secondary device 624, respectively. Further, the first primary device 612 and the first secondary device 614 are operating in the first piconet 610 using a first communication mode based on Time Division Duplexing (TDD) using an Inter Frame Space (IFS). In some embodiments, the first communication mode is based on TDD using a variable IFS. Furthermore, the second primary device 622 and the second secondary device 624 are operating in the second piconet 620. As previously mentioned, in some embodiments, the second primary device 622 and the second secondary device 624 are operating using the first communication mode. However, it should be understood that the second primary device 622 and the second secondary device 624 may be legacy devices operating using a communication mode, e.g. a legacy communication mode, different from the first communication mode. Thereby coexistence, e.g. transmission and/or reception time coordination during concurrent operation with the second primary device 622, is ensured by the first primary device 612 on its own. The legacy communication mode may for example be the communication mode used by an old BLE device not capable of varying the IFS.

In some embodiments, the first primary device 612 comprises an input and/or output interface 800 configured to communicate with one or more other primary devices, such as the second primary device 622, one or more secondary devices, such as the primary secondary device 614. The input and/or output interface 800 may comprise a wireless receiver and a wireless transmitter.

The first primary device 612 is configured to receive, e.g. by means of a receiving module 801 configured to receive, information from the second primary device 622, which information relates to a length of a data packet M2,S2 to be transmitted from or that is received by the second primary device 622. The first primary device 612 may further be configured to receive, e.g. by means of the receiving module 801 configured to receive, the first secondary device data packet S1 transmitted from the first secondary device 614. The receiving module 801 may be the wireless receiver or a processor 806 of the first primary device 612. The processor 806 will be described in more detail below.

As previously described, in some of the first embodiments, the received information comprises information about the length of a second secondary device data packet S2 transmitted from the second secondary device 624 to the second primary device 622. In Action 702 below it will be described how this information may be used.

Further, as described above, in some of the second, third and fourth

embodiments, the received information comprises information about the length of a second primary device data packet M2 to be transmitted from the second primary device 622 to the second secondary device 624.

Furthermore, as previously described in some of the third and fourth embodiments relating to indirect control, the received information comprises information about the length of the second secondary device data packet S2 transmitted from the second secondary device 624 to the second primary device 422.

Yet further, as previously described, in some of the fifth embodiments, the received information comprises information about the length of the second primary device data packet M2 to be transmitted from the second primary device 622.

In some of the sixth embodiments, and as previously described, the received information comprises information about the length of a data packet to be transmitted or that is received by the second primary device 622. The first primary device 612 is configured to transmit, e.g. by means of a transmitting module 802 configured to transmit, the first primary device data packet M1 to the first secondary device 614 in accordance with the received information. Thereby, transmission and/or reception time coordination during concurrent operation of the first primary device 612 and the second primary device 622 is provided. The transmitting module 802 may be the wireless transmitter or the processor 805 of the first primary device 612.

In some of the first embodiments, when the received information comprises information about the length of the second secondary device data packet S2 transmitted from the second secondary device 424 to the second primary device 622, and in order to transmit the first primary device data packet M 1 in accordance with the received information, the first primary device may be configured to delay transmission of the first primary device data packet M 1 until the second primary device 622 has received the second secondary device data packet S2. This may be the case when the second secondary device data packet S2 has a length that is longer than the length of the first secondary device data packet S1 transmitted from the first secondary device 614 to the first primary device 612.

In some of the first embodiments relating to direct control, wherein the first primary device 612 has determined an IFS value as will be described below, the first primary device 612 may be configured to delay the transmission of the first primary device data packet M1 by the determined IFS value.

As previously mentioned, in some of the second embodiments relating to indirect control, the received information comprises information about the length of the second primary device data packet M2 to be transmitted from the second primary device 622 to the second secondary device 624. When the first primary device 612 has determined, based on the received information, that the first secondary device 614 needs to delay its transmission of the first secondary device data packet S1 to the first primary device 612, and in order to transmit the first primary device data packet M 1 in accordance with the received information, the first primary device 612 is configured to transmit to the first secondary device 612 the first primary device data packet M1 comprising information relating to the needed transmission delay.

As mentioned above, in some of the third and fourth embodiments relating to direct control, the received information comprises information about the length of the second primary device data packet M2 to be transmitted from the second primary device 622 to the second secondary device 624. When the length of the first primary device data packet M1 has been adjusted in dependence of the received information, the first primary device 612 is configured to transmit the adjusted first primary device data packet M 1 to the first secondary device 614.

As mentioned previously, in some of the third and fourth embodiments relating to indirect control, the received information comprises information about the length of the second secondary device data packet S2 transmitted from the second secondary device 624 to the second primary device 622. When the second secondary device data packet S2 has a length that is longer than a length of the first secondary device data packet S1 transmitted from the first secondary device 614 to the first primary device 612; and in order to transmit the first primary device data packet M 1 in accordance with the received information, the first primary device 612 is configured to, the first primary device 612 is configured to transmit to the first secondary device 614 the first primary device data packet M1 comprising information instructing the first secondary device 614 to adjust the length of the first secondary device data packet S1.

As mentioned previously, in some of the fifth embodiments which may relate to both direct control and indirect control, the received information comprises information about an agreed data packet length.

In such fifth embodiments relating to direct control and in order to transmit the first primary device data packet M 1 in accordance with the received information, the first primary device 612 is configured to, when a first sub-packet M11 comprised in the first primary device data packet M1 is determined to relate to a voice packet based on a comparison with the agreed data packet length, transmit a first sub-packet M1 1 on a first logical link corresponding to a voice connection, otherwise the first primary device 612 is configured to transmit a second sub-packet M12 comprised in the first primary device data packet M1 on a second logical link corresponding to a data connection. This is

schematically illustrated in Figure 14, which will be described in more detail below.

In some fifth embodiments relating to indirect control and in order to transmit the first primary device data packet M1 in accordance with the received information, the first primary device 612 is configured to transmit to the first secondary device 614 the first primary device data packet M1 comprising information relating to the agreed data packet length.

In some of the sixth embodiments relating to direct control, when the first primary device 612 has determined, based on the received information, that a second

communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration, and in order to transmit the first primary device data packet M1 to the first secondary device 614 in accordance with the received information, the first primary device 612 is configured to transmit the first primary device data packet M1 during the fixed time slot duration.

Further, in some sixth embodiments relating to indirect control and in order to transmit the first primary device data packet M 1 in accordance with the received information, the first primary device 612 is configured to transmit to the first secondary device 614 the first primary device data packet M1 comprising information instructing the first secondary device 614 that a second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration. The first primary device 612 may further be configured to determine, e.g. by means of a determining module 803 configured to determine, one or more of the IFS value, the need of a transmission delay, the length of one or more data packets, the difference in length between two data packets, the communication mode, or other information relating thereto, etc.

The determining module 803 may be the processor 806 of the first primary device

612.

In some of the first embodiments, when the received information comprises information about the length of the second secondary device data packet S2 transmitted from the second secondary device 424 to the second primary device 622, the first primary device 612 may further be configured to determine an IFS value based on the length of the second secondary device data packet S2.

In some of the second embodiments relating to indirect control, when the received information comprises information about the length of the second primary device data packet M2 to be transmitted from the second primary device 622 to the second secondary device 624, the first primary device 612 may further be configured to determine, based on the received information, whether the first secondary device 614 needs to delay its transmission of the first secondary device data packet S1 to the first primary device 612.

In some of the third and fourth embodiments relating to direct control, when the received information comprises information about the length of the second primary device data packet M2 to be transmitted from the second primary device 622 to the second secondary device 624, the first primary device 612 is configured to determine, based on the received information, whether the second primary device data packet M2 has a length that is longer than the length of the first primary device data packet M1 to be transmitted from the first primary device 612 to the first secondary device 622.

In some of the third and fourth embodiments relating to indirect control, when the received information comprises information about the length of the second secondary device data packet S2 transmitted from the second secondary device 624 to the second primary device 622, the first primary device 612 is configured to determine, based on the received information, whether the second secondary device data packet S2 has a length that is longer than a length of the first secondary device data packet S1 transmitted from the first secondary device 614 to the first primary device 612.

In some of the sixth embodiments, the first primary device 612 is configured to determine, based on the received information, that a second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration.

The first primary device 612 may further be configured to adjust, e.g. by means of an adjusting module 804, adjust the length of a data packet.

The adjusting module 804 may be the processor 806 of the first primary device

612.

In some of the third and fourth embodiments relating to direct control, when the received information comprises information about the length of the second primary device data packet M2 to be transmitted from the second primary device 622 to the second secondary device 624, and when the length of the second primary device data packet M2 is longer than the length of the first primary device data packet M1 , the first primary device 612 is configured to adjust the length of the first primary device data packet M1 in dependence of the received information.

In some of the third embodiments, the first primary device 612 is configured to adjust the length of the first primary device data packet M1 in dependence of the received information by further being configured to adjust the length of the first primary device data packet M1 to become equal or almost equal to the length of the second primary device packet M2 by means of zero-padding.

In some of the fourth embodiments, the first primary device 612 is configured to adjust the length of the first primary device data packet M 1 in dependence of the received information by further being configured to adjust the length of the first primary device data packet M1 to become equal or almost equal to the length of the second primary device packet M2 by selecting a suitable Modulation and Coding Scheme (MCS).

The first primary device 612 may also comprise means for storing data such as user code data, e.g. information relating to one or more primary devices such as the first primary device 612 and the second primary device 622, to one or more secondary devices such as the first secondary device 614 and the second secondary device 624, and relating to IFS values, e.g. determined IFS values, transmission delays, data packet lengths and communications modes, etc. In some embodiments, the first primary device 612 comprises a memory 805 configured to store the data. The user code data may be processed or non-processed user code data and/or information relating thereto. The memory 805 may comprise one or more memory units. Further, the memory 805 may be a computer data storage or a semiconductor memory such as a computer memory, a read-only memory, a volatile memory or a non-volatile memory. The memory 805 is arranged to be used to store obtained and/or determined information in order to perform the methods herein when being executed in the first primary device 612. Embodiments herein for providing transmission and/or reception time coordination during concurrent operation with the second primary device 622 may be implemented through one or more processors, such as the processor 806 in the arrangement depicted in Fig. 8, together with computer program code for performing the functions and/or method actions of embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the first primary device 612. One such carrier may be in the form of an electronic signal, optical signal, radio signal or computer readable storage medium. The computer readable storage medium may be a CD ROM disc or a memory stick.

The computer program code may furthermore be provided as pure program code on a server and downloaded to the first primary device 612.

Those skilled in the art will also appreciate that the receiving module, the transmitting module, the determining module and the adjusting module described above may refer to a combination of analog and digital circuits, and/or one or more processors configured with software and/or firmware, e.g. stored in the memory, that when executed by the one or more processors such as the processors in the first primary device 612 perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuitry (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a- Chip (SoC).

A method performed in embodiments of the first secondary device 614 for providing transmission and/or reception time coordination during concurrent operation of the first primary device and the second primary device 622 will now be described with reference to Figure 9. As mentioned above, the first primary device 612 and the second primary device 622 are collocated and arranged in communication with the first secondary device 614 and the second secondary device 624, respectively. Further, the first primary device 612 and the first secondary device 614 are operating in the first piconet 610 using a first communication mode based on Time Division Duplexing (TDD) using an Inter Frame Space (IFS). In some embodiments, the first communication mode is based on TDD using a variable IFS. Furthermore, the second primary device 622 and the second secondary device 624 are operating in the second piconet 620. As previously mentioned, in some embodiments, the second primary device 622 and the second secondary device 624 are operating using the first communication mode. However, it should be understood that the second primary device 622 and the second secondary device 624 may be legacy devices operating using a communication mode, e.g. a legacy communication mode, different from the first communication mode. Thereby coexistence, e.g. transmission and/or reception time coordination during concurrent operation with the second primary device 622, is ensured by the first primary device 612 on its own. As previously mentioned, the legacy communication mode may for example be the communication mode used by an old BLE device not capable of varying the IFS

The method comprises one or more of the following actions. It should be understood that some actions are optional, that actions may be taken in another suitable order and that actions may be combined.

Action 901

The first secondary device 614 receives a first primary device data packet M1 from the first primary device 612, which first primary device data packet M1 comprises information relating to a length of the data packet M2,S2 to be transmitted from or that is received by the second primary device 614.

In some of the second embodiments relating to indirect control, the first primary device data packet M1 comprises information relating to whether the first secondary device 614 needs to delay its transmission of the first secondary device data packet S1 to the first primary device 612.

In some of the third and fourth embodiments relating to indirect control, the first primary device data packet M 1 comprises information instructing the first secondary device 614 to adjust the length of the first secondary device data packet S1 by means of zero-padding or by selecting a Modulation and Coding Scheme (MCS) that adjusts the length of the first secondary device data packet S1. Thereby, the length of the first secondary device data packet S1 becomes equal or almost equal to the length of the second secondary device data packet S2.

In some of the sixth embodiments relating to indirect control, the first primary device data packet M 1 comprises information instructing the first secondary device 614 that a second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration.

5 Action 902

The first secondary device 614 transmits the first secondary device data packet S1 to the first primary device 612 in accordance with the information comprised in the first primary device data packet M1 , whereby transmission and/or reception time coordination during concurrent operation of the first primary device 612 and the second primary device

10 622 is provided.

In some sixth embodiments relating to indirect control, when the first primary device data packet M 1 comprises information instructing the first secondary device 614 that the second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot

15 duration, the first secondary device 614 is configured to transmit the first secondary

device data packet S1 to the first primary device 612 in accordance with the received information by further being configured to transmit the first secondary device data packet S1 using the second communication mode.

20

To perform the method for providing transmission and/or reception time coordination during concurrent operation of the first primary device 612 and the second primary device 622, the first secondary device 614 may comprise an arrangement depicted in Figure 10. As previously mentioned, the first primary device 612 and the

25 second primary device 622 are collocated and arranged in communication with the first secondary device 614 and the second secondary device 624, respectively. Further, the first primary device 612 and the first secondary device 614 are operating in the first piconet 610 using a first communication mode based on Time Division Duplexing (TDD) using an Inter Frame Space (IFS). In some embodiments, the first communication mode is

30 based on TDD using a variable IFS. Furthermore, the second primary device 622 and the second secondary device 624 are operating in the second piconet 620. As previously mentioned, in some embodiments, the second primary device 622 and the second secondary device 624 are operating using the first communication mode. However, it should be understood that the second primary device 622 and the second secondary

35 device 624 may be legacy devices operating using a communication mode, e.g. a legacy communication mode, different from the first communication mode. Thereby coexistence, e.g. transmission and/or reception time coordination during concurrent operation with the second primary device 622, is ensured by the first primary device 612 on its own. As previously mentioned, the legacy communication mode may for example be the communication mode used by an old BLE device not capable of varying the IFS

In some embodiments, the first secondary device 614 comprises an input and/or output interface 1000 configured to communicate with one or more primary devices, such as the first primary device 612. The input and/or output interface 1000 may comprise a wireless receiver and a wireless transmitter.

The first secondary device 614 is configured to receive, e.g. by means of a receiving module 1001 configured to receive, a first primary device data packet M1 from the first primary device 612. The receiving module 1001 may be the wireless receiver or a processor 1004 of the first secondary device 614. The processor 1004 will be described in more detail below.

As previously mentioned and in some of the second embodiments relating to indirect control, the first primary device data packet M1 comprises information relating to whether the first secondary device 614 needs to delay its transmission of the first secondary device data packet S1 to the first primary device 612.

As mentioned above, in some of the third and fourth embodiments relating to indirect control, the first primary device data packet M1 comprises information instructing the first secondary device 614 to adjust the length of the first secondary device data packet S1 by means of zero-padding or by selecting a Modulation and Coding Scheme (MCS) that adjusts the length of the first secondary device data packet S1. Thereby, the length of the first secondary device data packet S1 becomes equal or almost equal to the length of the second secondary device data packet S2.

As previously mentioned, in some of the sixth embodiments relating to indirect control, the first primary device data packet M1 comprises information instructing the first secondary device 614 that a second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration. The first secondary device 614 is configured to transmit, e.g. by means of a transmitting module 1002 configured to transmit, a first secondary device data packet S1 to the first primary device 612 in accordance with information comprised in the received first primary device data packet M1. Thereby, transmission and/or reception time coordination during concurrent operation of the first primary device 612 and the second primary device 622 is provided. The transmitting module 1002 may be the wireless transmitter or the processor 1004 of the first secondary device 614.

As previously mentioned, in some of the sixth embodiments relating to indirect control, the first primary device data packet M1 comprises information instructing the first secondary device 614 that a second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration. In such embodiments, the first secondary device 614 is configured to transmit the first secondary device data packet S1 to the first primary device 612 in accordance with the received information by being configured to transmit the first secondary device data packet S1 using the second communication mode.

The first secondary device 614 may also comprise means for storing data such as user code data, e.g. information relating to one or more primary devices such as the first primary device 612 and the second primary device 622, to one or more secondary devices such as the first secondary device 614 and the second secondary device 624, and relating to IFS values, e.g. determined IFS values, transmission delays, data packet lengths and communications modes, etc. In some embodiments, the first secondary device 614 comprises a memory 1003 configured to store the data. The user code data may be processed or non-processed user code data and/or information relating thereto. The memory 1003 may comprise one or more memory units. Further, the memory 1003 may be a computer data storage or a semiconductor memory such as a computer memory, a read-only memory, a volatile memory or a non-volatile memory. The memory 1003 is arranged to be used to store obtained and/or determined information in order to perform the methods herein when being executed in the first secondary device 614.

Embodiments herein for providing transmission and/or reception time coordination during concurrent operation of the first primary device 612 and the second primary device 622 may be implemented through one or more processors, such as the processor 1004 in the arrangement depicted in Fig. 10, together with computer program code for performing the functions and/or method actions of embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the first secondary device 614. One such carrier may be in the form of an electronic signal, optical signal, radio signal or computer readable storage medium. The computer readable storage medium may be a CD ROM disc or a memory stick.

The computer program code may furthermore be provided as pure program code on a server and downloaded to the first secondary device 614.

Those skilled in the art will also appreciate that the receiving module, the transmitting module, the determining module and the adjusting module described above may refer to a combination of analog and digital circuits, and/or one or more processors configured with software and/or firmware, e.g. stored in the memory, that when executed by the one or more processors such as the processors in the first secondary device 614 perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuitry (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a- Chip (SoC).

Exemplifying embodiments

Exemplifying embodiments will now be described in more detail with reference to Figures 11 -14 schematically illustrating transmissions between primary devices and secondary devices.

As described in the background section, there are potential issues using fixed IFS in cases wherein more than one master device, e.g. more than one primary device, is active within the same common device, e.g. communications device, due to the rather large risk that one of the master devices is transmitting at the same time as another master device is receiving. Below a number of embodiments are disclosed that address this problem. The descriptions are made using terminology and numerical values that largely correspond to what is used in BLE. However, as is clear for anyone of ordinary skill in the art, these embodiments are by no means restricted to BLE.

Some first embodiments - Alignment by variable IFS and coordination In some first embodiments relating to e.g. Actions 701 ,702, and 708 above, alignment of the transmission and reception between two or more master devices are achieved by using a variable IFS as illustrated in Figure 1 1. As is seen, the durations of the different packets are similar to those in the example in the background section.

However, in some first embodiments, the first and second primary devices 612, 622 are exchanging information about the durations of the various packets. Upon reception of the initial parts of packets S1 and S2, the two primary devices 612, 622 determine, based on the received information, that packet S2 is longer than packet S1.

One way to use this information is to delay the transmission from the first primary device 612 such that it is aligned with the transmission from the second primary device 622. It is here assumed that the minimum T_IFS is 150με, although embodiments herein of course would be equally applicable for other values of the minimum T_IFS. A more efficient alternative, which is illustrated in Figure 11 , is to let the first primary device 612 transmit as soon as possible as long as it does not interfere with the reception of packet S2. Specifically, the IFS for the first primary device 612 is chosen such that the transmission starts directly when S2 is received provided this gives an IFS of at least 150με, otherwise T_IFS = 150με is chosen. In Figure 1 1 , the dashed boxes for the first primary device 612 illustrate when the packet M1 would have been sent if T_IFS = 150με would have been used.

In the previous example, the IFS was only adjusted at the primary device side which is possible if the packets from the two primary devices 612,622 are sufficiently similar in length, i.e., the difference does not exceed the minimum T_IFS = 150με.

Because the two primary devices 612,622 are collocated, signalling between them is feasible. However, if the difference in packet length exceeds the minimum T_IFS, also the secondary device 614,624 need to be engaged to ensure successful operation. This is described in the some second embodiments.

Some second embodiments - Alignment by variable IFS and explicit signalling In Figure 12, the packet M2 from the second primary device 622 is significantly longer than the packet M1 from the first primary device 612, which implies that with a fixed IFS, the first secondary device 614 would start transmitting before the packet M2 from the second primary device 622 is finalized as indicted by the dotted box. This would result in severe interference of packet S1 at Masterl . To circumvent this, the first secondary device 614 delays its transmission until the second primary device 622 has finished transmitting. Contrary to some first embodiments where both receivers were in the same device and signalling between the primary devices 612, 622 was feasible, in some second embodiments relating to e.g. Actions 701 , 703, and 708 above, the need to delay the transmission is explicitly signalled in the packet M1. Specifically, before the two primary devices 612, 622 start their transmissions, they exchange information about the length of their respective packet M1 , M2. Based on this information, the primary device 612, 622 having the shortest packet, e.g. the first primary device 612 in this example, sends information to the first secondary device 614 concerning how much extra it needs to delay the transmission of the first secondary device data packet S1 compared to the minimum T_IFS. In Figure 12, the transmission from the first secondary device 614 is indicated for the first packet. For the second packet it is seen that although the packets from the two primary devices 612, 622 do not end at the same time, there is no need to delay the transmission from the second secondary device 624 as the first primary device 612 will have finalized its transmission before the second primary device 614 starts to receive the second secondary device data packet S2.

Some third embodiments - Alignment by zero-padding

In the above first and second embodiments, the alignment was achieved by properly delaying transmissions, either at the primary device side, the secondary device side, or both sides. Another approach to achieve alignment is disclosed in some third embodiments relating to e.g. Actions 701 , 704, 705 and 708 above, wherein the alignment is achieved by ensuring that the packet lengths are sufficiently similar not to cause that one of the primary devices 612, 622 is transmitting when another is receiving. This is exemplified in Figure 13.

Here, in the first transmission, the data packet from the first primary device 612 is so much shorter that a response from the first secondary device 614 will be received while the second primary device 622 is still transmitting. To avoid this, first primary device 612 extends the packet M1 by zero-padding to get a total packet length that does match the packet length of corresponding packet M2 sent from the second primary device 622. Since the IFSs are the same, this ensures that the packets from the first secondary device 614 and second secondary device 624 will match in a similar way.

However, in this example the packet lengths from the first secondary device 614 and the second secondary device 624 also differ significantly and therefore first secondary device 614 uses zero-padding to get a packet length that matches that of the second secondary device 624. Referring to the figure 13 it is easy to see that if the first secondary device 614 would not use zero-padding, the response M1 from the first primary device 612 would start while the second primary device 622 would still be receiving and therefore most likely result in that packet S2 would not be correctly received. Contrary to the case when zero-padding is used by the primary device, the information regarding the need for zero-padding need to be transmitted over the air when zero-padding is used by the secondary device. This information may be sent in the packet from the primary device immediately preceding the packet from the secondary device that needs to be zero- padded. However, it may also be sent at an earlier moment in time in case the knowledge is available. In case the packet lengths for the secondary device are rather static, it could also be so that the use of zero-padding for a certain amount of time has been negotiated between the involved devices, e.g. involved primary devices and/or secondary devices.

Now, returning to the figure 13, in the next primary device-to-secondary device transmission, the two packets M1 , M2 from the primary devices 612,622 are of similar length and consequently none of the primary devices 612,622 need to use zero-padding. Finally, in the second secondary device-to-primary device transmission the same approach as for the first secondary device -to-primary device transmission is used.

Some fourth embodiments - Alignment by MCS selection

In some third embodiments, the durations for the different packets were aligned by means of zero-padding. Although this is a very simple approach, it is also somewhat wasteful as useless data is actually transmitted. In some fourth embodiments relating to e.g. Actions 701 , 704, 705 and 708 above, a slightly more complex, but less wasteful approach is disclosed.

It is quite common that a standard for wireless communication supports the use of different Modulation and Coding Schemes (MCS). When the channel conditions are good, an MCS that allows for more bits/s is used and when the channel conditions are bad, an MCS with less bits/s is used. Often different MCSs are given different numbers, e.g.

MCS0, MCS1 , MCS2, etc. where a higher number usually means a higher data rate, e.g. is less robust) This is what is meant when discussing in terms of higher and lower MSC.

Since it is desirable to transmit at a data rate as high as possible, one tries to find the highest MCS that may be supported without giving a too high error rate, e.g., a too high Bit Error Rate (BER) or Packet Error Rate (PER). The higher MCS that is used, the shorter the duration of the packets will be. Consider Figure 12 and the first packet M1 transmitted by the first primary device 612. Suppose MCS5 is found to be suitable based on the estimated link conditions, which also is the MCS that would be used in the absences of the transmission by the second primary device 622. However, when the first primary device 612 and the second primary device 622 exchange information about the durations of their respective packets M1 , M2, it will be found that the packet M1 from the first primary device 612 is much shorter than the packet M2 from the second primary device 622. According to some fourth embodiments, the first primary device 612 takes this into account and instead of transmitting using MCS5, a lower MCS is used, e.g. MCS2, such that the length is increased to match that of the packet M2 transmitted by the second primary device 622.

Herein matching of packet lengths do not necessarily mean that they are of exactly the same length, but rather that the lengths are sufficiently close to avoid that one of the primary devices is transmitting when another collocated primary device is receiving. That is, for the example above, it may have been possible for the first primary device 612 to instead select MCS4 or MCS6, such that the packet becomes either somewhat shorter or somewhat longer than the corresponding packet from the second primary device 622.

In case the alignment instead has to be done at the secondary device side, the information needs be signalled in a similar fashion as was described for some third embodiments.

Some fifth embodiments - Alignment by scheduling

In some fifth embodiments relating to e.g. Actions 701 , 706 and 708 above, rather than increasing the length of shorter packets by zero-padding or using a lower MCS, the alignment is obtained by scheduling packets of sufficiently similar length. In case the scheduling is in the primary device-to-secondary device direction, the two or more primary devices may agree on a target packet length and then only be allowed to transmit packets that are of this length or do not differ more than a predetermined duration from the target time.

As an example of some fifth embodiments, suppose that both the first primary device 612 and the second primary device 622 have two logical links active. The first logical link corresponding to a voice connection, implying that short packets are sent at regular intervals. The second logical link corresponding to data connection with best effort data, implying that packets of variable length may be sent at irregular intervals. According to some fifth embodiments, the two primary devices 612, 622 exchange information and arrange so that both the primary devices 612, 622 send the voice packets at the same time since this will ensure that at least some of the packets will be naturally aligned. As previously described and as schematically illustrated in Figure 14, when the first sub-packet M1 1 comprised in the first primary device data packet M 1 is determined to relate to a voice packet based on a comparison with the agreed data packet length, the first primary device 612 transmits the first sub-packet M 11 on the first logical link corresponding to the voice connection, otherwise the first primary device 612 transmits the second sub-packet M12 comprised in the first primary device data packet M1 on the second logical link corresponding to a data connection.

In other words, the first primary device 612 receives information about the data packet length from the second primary device 622, and based on this information the first primary device 612 decides to either send a voice message e.g. the sub-packet M11 , or a data message, e.g. the sub-packet M12, depending on which packet length is most suitable. In Figure 14, this is illustrated as the sub-packet M1 1 being selected for the first transmission since the packet length of the sub-packet M1 1 was suitable for the first transmission, whereas the sub-packet M12 is selected for the second transmission since the packet length of the sub-packet M12 was better for the second transmission.

The primary devices 612, 622 may then use any of the embodiments described above to align the data packets corresponding to the second logical link.

For the case that the scheduling is for the secondary device-to-primary device direction, this may or may not have to be explicitly signalled. Returning to the example above with the first logical link carrying voice, the voice link may be set up such that a secondary device-to-primary device voice transmission always follows a primary device- to-secondary device voice transmission. In this case there is no need to explicitly align the secondary device-to-primary device transmission, but rather this will be ensured by just aligning the primary device-to-secondary device transmission.

On the other hand, for less deterministic transmissions, such as those represented by the second logical link, explicit signalling for the secondary device-to-primary device transmission may be required as outlined in the embodiments above.

Some sixth embodiments - Alignment by switching to fixed TDD structure

The reason for having a fixed IFS, as in BLE, rather than fixed time slot durations, as in the classical Bluetooth, is increased efficiency. In particular for short packets, that only uses a small fraction of the slot duration, a fixed packet structure may be rather ineffective. However, a fixed TDD structure, where the transmissions from primary device- to-secondary device and secondary device-to-primary device are well defined and deterministic, may be beneficial to ensure coexistence in a simple way. In some sixth embodiments relating to e.g. Actions 701 , 707 and 708 above, the alignment is ensured by switching to a fixed TDD structure rather than an IFS, e.g. a nominal IFS, if found beneficial. The decision to switch to a fixed TDD may e.g. be based on that it is determined to give better performance, but it may also be based on that it is much less complex. In particular for situation when more than two primary devices are collocated, trying to align for a deterministic TDD structure may be expected to be considerably simpler than having to align for every single packet.

The decision to switch back from a fixed TDD frame structure to a fixed, e.g. nominal, IFS may be based on that the number of simultaneous active primary devices is reduced, say going from more than three to two. It may also be so based on that a typical duration of a packet has changed and become considerably shorter than the slot time used in the fixed TDD structure, making the fixed TDD structure ineffective.

As an alternative criterion for when to switch between a fixed IFS and fixed TDD structure is based on the load. Specifically, when more a certain percentage, say 20%, of the transmissions need to be aligned a fixed TDD structure is used, whereas otherwise a fixed IFS is used.

When using the word "comprise" or "comprising" it shall be interpreted as non- limiting, i.e. meaning "consist at least of". Further, when using the word "a", or "an" herein it should be interpreted as "at least one", "one or more", etc.

The embodiments herein are not limited to the above described preferred embodiments. Various alternatives, modifications and equivalents may be used.

Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appending claims.

Claims

1. A method in a first primary device (612) for providing transmission and/or

reception time coordination during concurrent operation with a second primary device (622), wherein the first and second primary devices (612, 622) are collocated and arranged in communication with a first secondary device (614) and a second secondary device (624), respectively, wherein the first primary device (612) and the first secondary device (614) are operating in a first piconet (610) using a first communication mode based on Time Division Duplexing, TDD, using an Inter Frame Space, IFS, wherein the second primary device (622) and the second secondary device (624) are operating in a second piconet (620), and wherein the method comprises:

- receiving (701) information from the second primary device (622) which information relates to a length of a data packet (M2,S2) to be transmitted from or that is received by the second primary device (622); and

- transmitting (708) a first primary device data packet (M1) to the first secondary device (614) in accordance with the received information, whereby transmission and/or reception time coordination during concurrent operation of the first primary device (612) and the second primary device (622) is provided.

2. The method of claim 1 , wherein the first communication mode is based on TDD using a variable IFS.

3. The method of claim 1 or 2, wherein when the received information comprises information about the length of a second secondary device data packet (S2) transmitted from the second secondary device (624) to the second primary device (622), and wherein transmitting (708) the first primary device data packet (M1) in accordance with the received information further comprises:

- when the second secondary device data packet (S2) has a length that is longer than a length of a first secondary device data packet (S1) transmitted from the first secondary device (614) to the first primary device (612), delaying transmission of the first primary device data packet (M 1) until the second primary device (614) has received the second secondary device data packet (S2).

The method of claim 3, further comprising:

- determining (702) an IFS value based on the length of the second secondary device data packet (S2); and wherein delaying the transmission of the first primary device data packet (M1) further comprises:

- delaying the transmission of the first primary device data packet (M1) by the determined IFS value.

The method of any of claims 1-4, wherein when the received information comprises information about the length of a second primary device data packet (M2) to be transmitted from the second primary device (622) to the second secondary device (624), and wherein the method further comprises:

- based on the received information, determining (703) whether the first secondary device (614) needs to delay its transmission of a first secondary device data packet (S1) to the first primary device (612); and wherein transmitting (708) the first primary device data packet (M1) further comprises:

- when determined that a transmission delay is needed, transmitting to the first secondary device (614) the first primary device data packet (M1) comprising information relating to the needed transmission delay.

The method of claim 1 or 2, wherein when the received information comprises information about the length of a second primary device data packet (M2) to be transmitted from the second primary device (622) to the second secondary device (624), and wherein the method further comprises:

- based on the received information, determining (704) whether the second primary device data packet (M2) has a length that is longer than the length of the first primary device data packet (M1) to be transmitted from the first primary device (612) to the first secondary device (614);

- when the length of the second primary device data packet (M2) is longer than the length of the first primary device data packet (M 1), adjusting (705) the length of the first primary device data packet (M1) in dependence of the received information; and wherein transmitting (708) the first primary device data packet (M 1) in accordance with the received information further comprises:

- transmitting the adjusted first primary device data packet (M1) to the first secondary device (614).

7. The method of claim 6, wherein adjusting (705) the length of the first primary device data packet (M 1) in dependence of the received information further comprises:

- by means of zero-padding, adjusting the length of the first primary device data packet (M1) to become equal or almost equal to the length of the second primary device packet (M2).

8. The method of claim 6, wherein adjusting (705) the length of the first primary

device data packet (M 1) in dependence of the received information further comprises:

- by selecting a Modulation and Coding Scheme, MCS, adjusting the length of the first primary device data packet (M1) to become equal or almost equal to the length of the second primary device packet (M2).

The method of any one of claims 6-8, wherein when the received information comprises information about the length of a second secondary device data packet (S2) transmitted from the second secondary device (624) to the second primary device (622), and wherein the method further comprises:

- based on the received information, determining (706) whether the second secondary device data packet (S2) has a length that is longer than a length of a first secondary device data packet (S1) transmitted from the first secondary device (614) to the first primary device (612); and wherein transmitting (708) the first primary device data packet (M1) comprises:

- when the length of the second secondary device data packet (S2) is longer than the length of the first secondary device data packet (S1), transmitting to the first secondary device (614) the first primary device data packet (M1) comprising information instructing the first secondary device (614) to adjust the length of the first secondary device data packet (S1).

10. The method of claim 1 or 2, wherein when the received information comprises information about an agreed data packet length, and wherein transmitting (708) the first primary device data packet (M1) in accordance with the received information further comprises:

- when a first sub-packet (M1 1) comprised in the first primary device data packet (M1) is determined to relate to a voice packet based on a comparison with the agreed data packet length, transmitting the first sub-packet (M1 1) on a first logical link corresponding to a voice connection; otherwise

- transmitting a second sub-packet (M12) comprised in the first primary device data packet (M1) on a second logical link corresponding to a data connection.

1 1. The method of claim 10, wherein transmitting (708) the first primary device data packet (M1) in accordance with the received information further comprises:

transmitting to the first secondary device (614) the first primary device data packet (M1) comprising information relating to the agreed data packet length.

12. The method of claim 1 or 2, further comprising:

- based on the received information, determining (707) that a second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration; and wherein transmitting (708) the first primary device data packet (M1) to the first secondary device (614) in accordance with the received information further comprises:

- transmitting the first primary device data packet (M 1) during the fixed time slot duration.

13. The method of claim 12, wherein transmitting (708) the first primary device data packet (M1) in accordance with the received information further comprises:

- transmitting to the first secondary device (614) the first primary device data packet (M 1) comprising information instructing the first secondary device (714) that a second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration.

14. A first primary device (612) for providing transmission and/or reception time

coordination during concurrent operation with a second primary device (622), wherein the first and second primary devices (612,622) are collocated and arranged in communication with a first secondary device (614) and a second secondary device (624), respectively, wherein the first primary device (612) and the first secondary device (614) are operating in a first piconet (610) using a first communication mode based on Time Division Duplexing, TDD, using an Inter Frame Space, IFS, wherein the second primary device (622) and the second secondary device (624) are operating in a second piconet (620), and wherein the first primary device (612) is configured to:

- receive information from the second primary device (622) which information relates to a length of a data packet (M2,S2) to be transmitted from or that is received by the second primary device (622); and

- transmit a first primary device data packet (M1) to the first secondary device (614) in accordance with the received information, whereby transmission and/or reception time coordination during concurrent operation of the first primary device (612) and the second primary device (622) is provided.

15. The first primary device (612) of claim 14, wherein the first communication mode i based on TDD using a variable IFS.

16. The first primary device (612) of claim 14 or 15, wherein when the received

information comprises information about the length of a second secondary device data packet (S2) transmitted from the second secondary device (424) to the second primary device (622), and wherein the first primary device (612) is configured to transmit the first primary device data packet (M1) in accordance with the received information by being configured to:

- when the second secondary device data packet (S2) has a length that is longer than a length of a first secondary device data packet (S1) transmitted from the first secondary device (614) to the first primary device (612), delay

transmission of the first primary device data packet (M 1) until the second primary device (622) has received the second secondary device data packet (S2).

17. The first primary device (612) of claim 16, further configured to:

- determine an IFS value based on the length of the second secondary device data packet (S2); and wherein the first primary device (612) is configured to delay the transmission of the first primary device data packet (M1) by being configured to:

- delay the transmission of the first primary device data packet (M1) by the determined IFS value.

18. The first primary device (612) of any of claims 14-17, wherein when the received information comprises information about the length of a second primary device data packet (M2) to be transmitted from the second primary device (622) to the second secondary device (624), and wherein the first primary device (612) is configured to:

- based on the received information, determine whether the first secondary device (614) needs to delay its transmission of a first secondary device data packet (S1) to the first primary device (612); and wherein the first primary device

(612) is configured to transmit the first primary device data packet (M1) by being configured to:

- when determined that a transmission delay is needed, transmit to the first secondary device (612) the first primary device data packet (M1) comprising information relating to the needed transmission delay.

19. The first primary device (612) of claim 14 or 15, wherein when the received

information comprises information about the length of a second primary device data packet (M2) to be transmitted from the second primary device (622) to the second secondary device (624), and wherein the first primary device (612) further is configured to:

- based on the received information, determine whether the second primary device data packet (M2) has a length that is longer than the length of the first primary device data packet (M1) to be transmitted from the first primary device (612) to the first secondary device (622);

- when the length of the second primary device data packet (M2) is longer than the length of the first primary device data packet (M1), adjust the length of the first primary device data packet (M1) in dependence of the received information; and wherein the first primary device (612) is configured to transmit the first primary device data packet (M1) in accordance with the received information by being configured to:

- transmit the adjusted first primary device data packet (M1) to the first secondary device (614).

20. The first primary device (612) of claim 19, wherein the first primary device (612) is configured to adjust the length of the first primary device data packet (M1) in dependence of the received information by being configured to:

- by means of zero-padding, adjust the length of the first primary device data packet (M1) to become equal or almost equal to the length of the second primary device packet (M2).

21. The first primary device (612) of claim 19, wherein the first primary device (612) is configured to adjust the length of the first primary device data packet (M1) in dependence of the received information by being configured to:

- by selecting a Modulation and Coding Scheme, MCS, adjust the length of the first primary device data packet (M1) to become equal or almost equal to the length of the second primary device packet (M2).

22. The first primary device (612) of any one of claims 19-21 , wherein when the

received information comprises information about the length of a second secondary device data packet (S2) transmitted from the second secondary device (624) to the second primary device (622), and wherein the first primary device (612) is configured to:

- based on the received information, determine whether the second secondary device data packet (S2) has a length that is longer than a length of a first secondary device data packet (S1) transmitted from the first secondary device (614) to the first primary device (612); and wherein the first primary device (612) is configured to transmit the first primary device data packet (M1) by being configured to:

- when the length of the second secondary device data packet (S2) is longer than the length of the first secondary device data packet (S1), transmit to the first secondary device (614) the first primary device data packet (M1) comprising information instructing the first secondary device (614) to adjust the length of the first secondary device data packet (S1).

23. The first primary device (612) of claim 14 or 15, wherein when the received

information comprises information about an agreed data packet length and wherein the first primary device (612) is configured to transmit the first primary device data packet (M 1) in accordance with the received information by being configured to:

when a first sub-packet (M1 1) comprised in the first primary device data packet (M1) is determined to relate to a voice packet data based on a comparison with the agreed data packet length, transmit the first sub-packet (M1 1) on a first logical link corresponding to a voice connection; otherwise

- transmit a second sub-packet (M12) comprised in the first primary device data packet (M1) on a second logical link corresponding to a data connection.

The first primary device (612) of claim 23, wherein the first primary device (612) is configured to transmit the first primary device data packet (M1) in accordance with the received information by being configured to:

- transmit to the first secondary device (614) the first primary device data packet (M1) comprising information relating to the agreed data packet length.

The first primary device (612) of claim 14 or 15, further configured to:

- based on the received information, determine that a second

communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration; and wherein the first primary device (612) is configured to transmit the first primary device data packet (M1) to the first secondary device (614) in accordance with the received information by being configured to:

- transmit the first primary device data packet (M1) during the fixed time slot duration.

The first primary device (612) of claim 25, wherein the first primary device (612) is configured to transmit the first primary device data packet (M1) in accordance with the received information by further being configured to:

- transmit to the first secondary device (614) the first primary device data packet (M1) comprising information instructing the first secondary device (614) that a second communication mode is to be used instead of the first

communication mode, which second communication mode is based on TDD with a fixed time slot duration.

27. A method in a first secondary device (614) for providing transmission and/or

reception time coordination during concurrent operation of a first primary device (612) and a second primary device (622), wherein the first and second primary devices (612,622) are collocated and arranged in communication with the first secondary device (614) and a second secondary device (624), respectively, wherein the first primary device (612) and the first secondary device (614) are operating in a first piconet (610) using a first communication mode based on Time

Division Duplexing, TDD, using an Inter Frame Space, IFS, wherein the second primary device (622) and the second secondary device (624) are operating in a second piconet (620), and wherein the method comprises:

- receiving (901) a first primary device data packet (M1) from the first primary device (612), which first primary device data packet (M 1) comprises information relating to a length of a data packet (M2,S2) to be transmitted from or that is received by the second primary device (614); and

- transmitting (902) a first secondary device data packet (S1) to the first primary device (612) in accordance with the information comprised in the first primary device data packet (M1), whereby transmission and/or reception time coordination during concurrent operation of the first primary device (612) and the second primary device (622) is provided.

28. The method of claim 27, wherein the first communication mode is based on TDD using a variable IFS.

29. The method of claims 27 or 28, wherein the first primary device data packet (M1) comprises information relating to whether the first secondary device (614) needs to delay its transmission of the first secondary device data packet (S1) to the first primary device (612).

30. The method of any one of claims 27 or 28, wherein the first primary device data packet (M1) comprises information instructing the first secondary device (614) to adjust the length of the first secondary device data packet (S1) by means of zero- padding or by selecting a Modulation and Coding Scheme, MCS, that adjusts the length of the first secondary device data packet (S1), whereby the length of the first secondary device data packet (S1) becomes equal or almost equal to the length of the second secondary device data packet (S2).

31. The method of claim 27 or 28, wherein the first primary device data packet (M1) comprises information instructing the first secondary device (614) that a second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration; and wherein transmitting (902) the first secondary device data packet (S1) to the first primary device (612) in accordance with the received information comprises:

- transmitting the first secondary device data packet (S1) using the second communication mode.

32. A first secondary device (614) for providing transmission and/or reception time coordination during concurrent operation of a first primary device (612) and a second primary device (622), wherein the first and second primary devices (612,622) are collocated and arranged in communication with the first secondary device (614) and a second secondary device (624), respectively, wherein the first primary device (612) and the first secondary device (614) are operating in a first piconet (610) using a first communication mode based on Time Division

Duplexing, TDD, using an Inter Frame Space, IFS, wherein the second primary device (622) and the second secondary device (624) are operating in a second piconet (620), and wherein the first secondary device (614) is configured to:

- receive a first primary device data packet (M1) from the first primary device (612), which first primary device data packet (M1) comprises information relating to a length of a data packet (M2,S2) to be transmitted from or that is received by the second primary device (622); and

- transmit a first secondary device data packet (S1) to the first primary device (612) in accordance with the information comprised in the first primary device data packet (M1), whereby transmission and/or reception time coordination during concurrent operation of the first primary device (612) and the second primary device (622) is provided.

33. The first secondary device (614) of claim 32, wherein the first communication mode is based on TDD using a variable IFS.

34. The first secondary device (614) method of claims 32 or 33, wherein the first primary device data packet (M1) further comprises information relating to whether the first secondary device (614) needs to delay its transmission of the first secondary device data packet (S1) to the first primary device (612).

35. The first secondary device (614) method of any one of claims 32 or 33, wherein the first primary device data packet (M1) further comprises information instructing the first secondary device (614) to adjust the length of the first secondary device data packet (S1) by means of zero-padding or by selecting a Modulation and Coding Scheme, MCS, that adjusts the length of the first secondary device data packet (S1), whereby the length of the first secondary device data packet (S1) becomes equal or almost equal to the length of the second secondary device data packet (S2).

36. The first secondary device (614) of claim 32 or 33, wherein the first primary device data packet (M 1) further comprises information instructing the first secondary device (614) that a second communication mode is to be used instead of the first communication mode, which second communication mode is based on TDD with a fixed time slot duration; and wherein the first secondary device (614) is configured to transmit the first secondary device data packet (S1) to the first primary device (612) in accordance with the received information by being configured to:

- transmit the first secondary device data packet (S1) using the second communication mode.

37. A computer program, comprising instructions which, when executed on at least one processor, causes the at least one processor to carry out the method according to any one of claims 1-13, 27-31.

38. A carrier comprising the computer program of claim 37, wherein the carrier is one of an electronic signal, optical signal, radio signal or computer readable storage medium.