CA2991885A1

CA2991885A1 - Transmitting device, receiving device and methods performed therein

Info

Publication number: CA2991885A1
Application number: CA2991885A
Authority: CA
Inventors: Leif Wilhelmsson; Bo Hagerman; Yi-Pin Eric Wang; Ali S. Khayrallah; Michael SAMUEL BEBAWY
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2014-07-09
Filing date: 2015-02-10
Publication date: 2016-01-14
Also published as: WO2016007060A1

Abstract

Embodiments herein relate to a method performed by a transmitting device (12) for transmitting a packet to a receiving device in a wireless communication network. The transmitting device (12): - determines one or more of: a radio channel condition of a channel between the transmitting device (12) and the receiving device (10), a coding rate or modulation of the packet, a coding rate of a header of the packet, and a quality of the transmitting device (12) and/or the receiving device (10); -determines a packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device (12) and/or the receiving device(10); and -transmits data with the determined packet structure to the receiving device (10).

Description

TRANSMITTING DEVICE, RECEIVING DEVICE AND METHODS PERFORMED
THEREIN
Technical field [0001] The present disclosure relates to a transmitting device, a receiving device and methods performed therein. Embodiments herein relate to wireless communication and in particular to methods and devices for communicating data using a flexible packet structure.
Background

[0002] In a typical wireless communication network, devices, also known as mobile stations and/or user equipments (UEs), communicate via a Radio Access Network (RAN) to one or more core networks (CN). The RAN covers a geographical area which is divided into cell areas, with each cell area being served by a base station, e.g., a radio base station (RBS), which in some networks may also be called, for example, a "NodeB" or "eNodeB". A cell is a geographical area where radio coverage is provided by the radio base station at a base station site or an antenna site in case the antenna and the radio base station are not collocated.
Each cell is identified by an identity within the local radio area, which is broadcast in the cell. Another identity identifying the cell uniquely in the whole wireless communication network is also broadcast in the cell. One base station may have one or more cells. The base stations communicate over the air interface operating on radio frequencies with the devices within range of the base stations.

[0003] A Universal Mobile Telecommunications System (UMTS) is a third generation mobile communication system, which evolved from the second generation (2G) Global System for Mobile Communications (GSM). The UMTS
terrestrial radio access network (UTRAN) is essentially a RAN using wideband code division multiple access (WCDMA) and/or High Speed Packet Access (HSPA) for devices. In a forum known as the Third Generation Partnership Project (3GPP), telecommunications suppliers propose and agree upon standards for third generation networks and UTRAN specifically, and investigate enhanced data rate and radio capacity. In some versions of the RAN as e.g. in UMTS, several base stations may be connected, e.g., by landlines or microwave, to a controller node, such as a radio network controller (RNC) or a base station controller (BSC), which supervises and coordinates various activities of the plural base stations connected thereto. The RNCs are typically connected to one or more core networks.

[0004] Specifications for the Evolved Packet System (EPS) have been completed within the 3rd Generation Partnership Project (3GPP) and this work continues in the coming 3GPP releases. The EPS comprises the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), also known as the Long Term Evolution (LTE) radio access, and the Evolved Packet Core (EPC), also known as System Architecture Evolution (SAE) core network. E-UTRAN/LTE is a variant of a 3GPP radio access technology wherein the radio base stations are directly connected to the EPC core network rather than to RNCs. In general, in E-UTRAN/LTE the functions of a RNC are distributed between the radio base stations, e.g. eNodeBs in LTE, and the core network. As such, the Radio Access Network (RAN) of an EPS has an essentially "flat" architecture comprising radio base stations without reporting to RN Cs.

[0005] A radio spectrum is generally divided into different parts, e.g. a licensed spectrum or bands, which comprise bandwidths of frequencies that may be used by e.g. wireless communication networks such as GSM, UMTS, LTE, and an unlicensed spectrum or bands, which comprise bandwidths of frequencies that may be used by e.g. short range communicating device, e.g. between devices using Wireless Local Area Network (WLAN) or Bluetooth wireless technology.

[0006] The part of the available spectrum allocated to unlicensed frequency bands is relatively large. Common for many of these short range technologies is that they are based on ad-hoc methods and typically mandated courtesy roles to access the unlicensed frequency bands, e.g. Industrial, Scientific and Medical (ISM) bands. This may create an uncontrolled interference situation to operate in the unlicensed bands, normally quite different from the interference situation in licensed frequency bands. The communication operates under different radio channel conditions, ranging from good to really poor conditions with large dynamics. An example of a situation that may result in a good radio channel condition is when the devices are close to each other in a line-of-sight position.
Opposite, if the devices are far away from each other and the environment is such that there are objects like walls or large objects hindering and shadowing the radio signals these situations may create a poor radio channel condition. The short range technologies are often operated without any power control mechanism.

[0007] These short range technologies are commonly having relaxed specifications based on old architectures. Some devices may operate with much better performance and even largely exceeding what is a minimum performance required in the specifications.

[0008] Pilot symbols and synchronisation in particular should be sufficiently good for the most robust coding and modulation used for the data. This means that in case there is a large difference in robustness for the data, the synchronization may be unnecessarily good and thus may result in an unnecessary overhead when designed for a worst radio channel condition scenario but operated at a different, better, radio channel condition. Another issue is that different implementations of the same standard may have different performances. An example could be a link between devices of different performances such as a link between a sensor and a network node. The sensor may be implemented using the most cost efficient and energy efficient technology in order to be as cheap as possible and to allow efficient operation on a coin cell battery. The network node, on the other hand, may be implemented with a radio link performance as the main design objective. This may effectively mean that it may be considerably simpler to demodulate a data packet transmitted from the network node, signal generated with high quality, than the same type of data packet transmitted from the sensor node. However, in case a receiving device, e.g. a sensor or the network node, has no information about the quality of the transmitted signal, it typically has to assume that the transmitted signal with the data packet is of a poor quality and thus will not be able to use more efficient methods in a receiving process relying on the signal is generated with a high quality. E.g. a first algorithm in the receiving device may be very robust to frequency error in a transmitted signal, but the algorithm has relatively poor sensitivity. The sensitivity is the same regardless whether the frequency error is zero or very large. A second algorithm may not be able to deal with large frequency errors, but in case there is no frequency error the performance is much better than for the robust one. Hence, the receiving device may use the first algorithm as it assumes a poor quality. This results in an inefficient use of radio resources that may affect the performance of the wireless communication network.
Summary

[0009] An object is to provide a mechanism for providing an improved performance of a wireless communication network.

[00010] According to an aspect of embodiments herein the object is achieved by providing a method performed by a transmitting device for transmitting a packet to a receiving device in a wireless communication network. The transmitting device determines one or more of: a radio channel condition of a channel between the transmitting device and the receiving device, a coding rate or modulation of the packet, a coding rate of a header of the packet, and a quality of the transmitting device and/or the receiving device. Furthermore, the transmitting device determines a packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device and/or the receiving device. The transmitting device then transmits data with the determined packet structure to the receiving device.

[00011] According to another aspect of embodiments herein the object is achieved by providing a method performed by a receiving device for receiving a packet from a transmitting device in a wireless communication network. The receiving device receives a packet with a packet structure from the transmitting device. The receiving device transmits, to the transmitting device, at least one of: a received signal quality at the receiving device, a quality of the receiving device, and a feedback relating to the previously received packet associated with a radio channel condition of a channel between the receiving device and the transmitting device. Furthermore, the receiving device receives data in an adjusted packet structure from the transmitting device, the adjusted packet structure being based on the radio channel condition and/or a quality of the transmitting device and/or the receiving device.

[00012] According to yet another aspect of embodiments herein the object is achieved by providing a transmitting device for transmitting a packet to a receiving device in a wireless communication network. The transmitting device is configured to determine one or more of: a radio channel condition of a channel between the transmitting device and the receiving device, a coding rate or modulation of the packet, a coding rate of a header of the packet, and a quality of the transmitting device and/or the receiving device. Furthermore, the transmitting device is configured to determine a packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device and/or the receiving device. The transmitting device is also configured to transmit data with the determined packet structure to the receiving device.

[00013] According to still another aspect of embodiments herein the object is achieved by providing a receiving device for receiving a packet from a transmitting device in a wireless communication network. The receiving device is configured to receive a packet with a packet structure from the transmitting device. The receiving device is further configured to transmit, to the transmitting device, at least one of: a received signal quality at the receiving device, a quality of the receiving device, and a feedback relating to the previously received packet associated with a radio channel condition of a channel between the receiving device and the transmitting device. The receiving device is further configured to receive data in an adjusted packet structure from the transmitting device, the adjusted packet structure being based on the radio channel condition and/or a quality of the transmitting device and/or the receiving device.

[00014] By determining the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device and/or the receiving device, the resources are efficiently used as the receiving device may use an appropriate algorithm for the radio channel condition/coding rate/modulation/quality of the devices, leading to an improved performance of the wireless communication network. Determining packet structure covers: determining synchronization word in the packet;
determining length of synchronization word or header in the packet;
determining density of pilot signals in the packet; and/or changing a coding or modulation for a header in the packet.
Brief description of drawings

[00015] Embodiments will now be described in more detail in relation to the accompanying drawings, in which:

[00016] Figure 1 is a schematic overview depicting a wireless communication network according to embodiments herein.

[00017] Figure 2a is a schematic flowchart depicting a method performed in a first communication device according to embodiments herein.

[00018] Figure 2b is a schematic flowchart depicting a method performed in a second communication device according to embodiments herein.

[00019] Figure 3a is an illustration of an example of a packet to be transmitted to a receiving device.

[00020] Figure 3b is an illustration of another example of a packet to be transmitted to a receiving device.

[00021] Figure 4 is an illustration of an example of a packet to be transmitted to a receiving device, wherein the (length of the) syncword is flexible.

[00022] Figure 5 is an illustration of an example of a packet to be transmitted to a receiving device, wherein the (length of the) syncword is dependent on the quality of the transmitting and/or the receiving device.

[00023] Figure 6 is an illustration of an example of a packet to be transmitted to a receiving device, wherein the density of the pilot symbols depends at least partly on a channel quality.

[00024] Figure 7 is an illustration of how successively longer syncwords may be generated.

[00025] Figure 8 is a flowchart of a method performed by a transmitting device for transmitting a packet to a receiving device according to an exemplifying embodiment.

[00026] Figure 9 is a block diagram of a transmitting device adapted for transmitting a packet to a receiving device according to an exemplifying embodiment.

[00027] Figure 10 is a block diagram of a transmitting device for transmitting a packet to a receiving device according to an exemplifying embodiment.

[00028] Figure 11 is a block diagram of an arrangement in a transmitting device adapted for transmitting a packet to a receiving device according to an exemplifying embodiment.

[00029] Figure 12 is a block diagram depicting a receiving device according to embodiments herein.

Detailed description

[00030] The figures are schematic and simplified for clarity, and they merely show details which are essential to the understanding of the embodiments presented herein, while other details have been left out. Throughout the disclosure, the same reference numerals are used for identical or corresponding parts or actions.

[00031] Embodiments herein relate to wireless communication networks in general. Fig. 1 is a schematic overview depicting a wireless communication network 1. The wireless communication network 1 comprises one or more RANs and one or more CNs. The wireless communication network 1 may use a number of different technologies, such as Long Term Evolution (LTE), LTE-Advanced, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications/Enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations. The wireless communication network 1 is exemplified herein as a Bluetooth network.

[00032] In the wireless communication network 1, a receiving device 10, exemplified as a wireless device, also known as a receiving communication device, e.g. a mobile station, a user equipment and/or a wireless terminal, communicates via a RAN to one or more CNs. It should be understood by the skilled in the art that "wireless device" is a non-limiting term which means any wireless terminal, user equipment, Machine Type Communication (MTC) device, a Device to Device (D2D) terminal, or node e.g. Personal Digital Assistant (PDA), laptop, mobile phone, sensor, relay, mobile tablets or even a small base station communicating within respective cell.

[00033] The wireless communication network 1 covers a geographical area which is divided into cell areas, e.g. a cell 11 being served by a radio access network node. The radio access network node is an example of a transmitting device 12.

The radio access network node may also be referred to as a radio base station such as a NodeB, an evolved Node B (eNB, eNode B), a base transceiver station, Access Point Base Station, base station router, or any other network unit capable of communicating with a wireless device within the cell 11 served by the radio access network node depending e.g. on the radio access technology and terminology used. The radio access network node may serve one or more cells, such as the cell 11.

[00034] A cell is a geographical area where radio coverage is provided by radio base station equipment at a base station site or at remote locations in Remote Radio Units (RRU). The cell definition may also incorporate frequency bands and radio access technology used for transmissions, which means that two different cells may cover the same geographical area but using different frequency bands.
Each cell is identified by an identity within the local radio area, which is broadcast in the cell. Another identity identifying the cell 11 uniquely in the whole wireless communication network 1 is also broadcasted in the cell 11. The radio access network node communicates over the air or radio interface operating on radio frequencies with the wireless device within range of the radio access network node. The wireless device transmits data over the radio interface to the radio access network node in Uplink (UL) transmissions and the radio access network node transmits data over an air or radio interface to the wireless device in Downlink (DL) transmissions.

[00035] Briefly described, methods, and apparatuses that are flexible and can adjust to the actual radio conditions to further optimise performance by minimising signalling overhead are provided. In exemplified embodiments herein the receiving device 10 is exemplified as a wireless device and the transmitting device 12 is exemplified as a radio access network node. However, the transmitting device may be the wireless device and the receiving device 10 may be the radio access network node, or both the receiving device 10 and the transmitting device 12 may be wireless devices, e.g. sensors, communicating.

[00036] To better address the increased market for low power wireless technologies with a large difference in implementations, data rate usage as well as a large difference in radio channel conditions, there is a need for the methods, and apparatuses that are flexible and can adjust to the actual radio channel conditions to further optimise performance by minimising overhead.

[00037] The method actions in the transmitting device 12 for transmitting a packet to the receiving device 10 in the wireless communication network 1 according to embodiments herein will now be described with reference to a flowchart depicted in Fig. 2a. The actions do not have to be taken in the order stated below, but may be taken in any suitable order. Actions performed in some embodiments are marked with dashed boxes.

[00038] Action 201. The transmitting device 12 may pair with the receiving device 10. During this pairing the transmitting device 12 and the receiving device 10 may exchange information such as quality of the different devices and/or radio channel conditions.

[00039] Action 202. The transmitting device 12 determines one or more of: a radio channel condition of a channel between the transmitting device 12 and the receiving device 10, a coding rate or modulation of the packet, a coding rate of a header of the packet, and a quality of the transmitting device 12 and/or the receiving device 10. The transmitting device 12 may determine the radio channel condition by determining at least one of: a received signal quality at the receiving device 10, and a feedback received from the receiving device 10 relating to a previously transmitted packet.

[00040] Action 203. The transmitting device 12 determines a packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10. For example, the transmitting device 12 may determine a synchronisation word in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10. Additionally or alternatively, the transmitting device 12 may determine the packet structure by determining a shorter synchronisation word when a higher coding rate is used for data than a synchronisation word when a lower coding rate is used for data.
The synchronisation word may be constructed by repeating one shorter synchronisation word an integer number of times. The transmitting device 12 may, additionally or alternatively, determine a density of pilot signals in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10. The transmitting device 12 may determine the packet structure by changing a coding or modulation for the header in the packet structure based on a coding or modulation used for a user data. The transmitting device may determine the packet structure by changing length of a header in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10. The transmitting device 12 determines or selects the packets structure to minimize overhead in the packet structure. That quality of the transmitting device 12 and/or the receiving device 10 is taken into account means that accuracy of the transmitting device 12 and/or the receiving device 10 may be taken into account when determining the packet structure.

[00041] Action 204. The transmitting device 12 transmits data with the determined packet structure to the receiving device 10.

[00042] The method actions performed in the receiving device 10 receiving a packet from the transmitting device 12 in the wireless communication network 1 according to some embodiments will now be described with reference to a flowchart depicted in Fig. 2b. The actions do not have to be taken in the order stated below, but may be taken in any suitable order. Actions performed in some embodiments are marked with dashed boxes.

[00043] Action 211. The receiving device 10 may pair with the transmitting device 12.

[00044] Action 212. The receiving device 10 receives a packet with a packet structure from the transmitting device 12.

[00045] Action 213. The receiving device 10 transmits to the transmitting device 12, at least one of: a received signal quality at the receiving device 10, a quality of the receiving device 10, and a feedback relating to the previously received packet associated with a radio channel condition of a channel between the receiving device 10 and the transmitting device 12.

[00046] Action 214. The receiving device 10 receives data in an adjusted packet structure from the transmitting device 12, the adjusted packet structure being based on the radio channel condition and/or the quality of the transmitting device 12 and/or the receiving device 10.

[00047] To ease the description, the description is made under the assumption that a packet comprises a synchronisation word, hereinafter referred to as a syncword, a header field, and a data field as illustrated in Figure 3a. The syncword may be used for synchronisation, for instance time and frequency estimation; the header field may comprise the address of the intended receiving device 10, and possibly also of the transmitting device 12 in case that is needed, the length of the packet, and the modulation and coding scheme that is used for the actual data; and the data field may comprise the actual data. In the art there may be other terms used, and also the exact way of processing may be different.
Instead of the syncword there may be a preamble and a syncword, and the contents of the header may vary. Also, the data field may contain some control information or may contain only user data. Regardless of which is the exact packet structure, the present disclosure is applicable. Figure 3b shows a packet with pilot symbols or pilots in the data field.

[00048] To further ease the description, suppose that the data may be coded by means of an error correcting code of different rates, where the possible rates are 1/L, where L = 2,4,8,16 is the order of redundancy. Here an increasing L, i.e., lowering the rate resulting in lower data payload rate, is assumed to give better sensitivity, i.e. the received signal can be decoded at a lower received power.
The sensitivity may be defined in absolute terms of the received power, e.g., -100 dBm, or it may be conveniently defined by the signal-to-noise-ratio (SNR), e.g. 3 dB. In embodiments described herein, the latter will be used.
Embodiments described herein will only discuss in terms of changed coding rate, assuming the same modulation is used all the time. In a more general case, both coding and modulation may be changed to make the transmission more or less robust. All embodiments also cover the case that also the modulation would have been possible to change, but for the sake of simplicity the examples are only discussing in terms of changing coding rate. One skilled in the art would understand how the embodiments are to be interpreted in case of more than one possible modulation format are used and how this relates to the data rate.

[00049] For the sake of illustration, suppose that L = 2 corresponds to a SNR=

dB, L = 4 corresponds to 0 dB, L = 8 corresponds to SNR = -3dB, and L = 16 corresponds to SNR = -6 dB. That is, for every doubling of L, a 3 dB gain in sensitivity is obtained.

[00050] The above numbers may correspond to a situation where the receiving device 10 has been properly synchronised to the transmitting device 12, i.e.
both time and frequency may have been estimated, compensations may have been made, etc. For this to be possible, a suitable syncword is needed. Basically, the lower the operating point, i.e., the lower the received SNR, the harder it becomes to synchronise. Suppose as for illustration, that the synchronisation is such that 32 bits are needed for SNR = 3 dB, 64 bits are needed for SNR = 0 dB, 128 bits are needed for SNR = -3 dB, and 256 bits are needed for SNR = -6dB.

[00051] Since synchronisation is needed for all values of L, this implies that a syncword of length 256 is needed in case the syncword is the same for all values of L since that a syncword of length 256 is needed for the worst targeted sensitivity operation condition when L is equal to 16. This effectively means that in case L = 2, (256-32) = 224 useless bits are transmitted in the syncword as it would have sufficed with a syncword of length 32.

[00052] According to embodiments herein the transmitting device 12 determines a radio channel condition, a coding rate of the packet, a coding rate of a header of the packet, and/or a quality of the transmitting device 12 and/or the receiving device 10, and then determines, e.g. adjusts, a packet structure based on the determined radio channel condition, the determined coding rate of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10. The transmitting device 12 then transmits data with the determined packet structure.

[00053] The channel radio condition may be determined based on at least one of:
a received signal quality at the receiving device 10, and a feedback received from the receiving device 10 relating to a previously transmitted packet.

[00054] In some embodiments disclosed herein, illustrated in figure 4, the transmitting device 12 may determine the packet structure by choosing a synchronisation word depending on the coding rate used for the data. Figure 4 shows a first packet with a first syncword 41, a first header 42 and a high rate data field 43, a second packet with a second syncword 44, a second header 45 and a medium rate data field 46, a third packet with a third syncword 47, a third header 48 and a low rate data field 49. Specifically, a shorter syncword may be selected the higher the coding rate, i.e. a smaller L. In another version of this embodiment, the longer syncwords are constructed by repeating one of the shorter syncwords an integer number of times. This is illustrated in Figure 5.

[00055] Also the coding required for the header may depend on the operating point/condition, so also covered by this embodiment is when the coding for the header may be selected based on the coding used for the user data. In Figure 6 this is illustrated. Thus this embodiment covers the case that at least one of the syncword and the coding scheme used for the header may be made flexible and may be selected based on the coding scheme used for the data payload.

[00056] Another property that may impact the performance of a receiver, i.e.
the receiving device 10, is the received signal accuracy of, for instance, the time and frequency. This may for instance be the spread, tolerance, in a crystal oscillator, but it could also be what kind of architecture and component quality that is used for implementing a transmitter. E.g. an accurate transmitter with an accuracy of lppm, means that this corresponds to a frequency error of 2.5 kHz when the carrier frequency is 2.5 GHz. For an inaccurate transmitter, with an accuracy of 50 ppm, the frequency error may instead be 125kHz. 'Accuracy may be used herein but also 'quality' of the transmitting device 12 and the receiving device 10 is used herein. Specifically, in case an accurate, stable, transmitter is used, it may be possible to perform coherent accumulation of a large number of bits, which is preferable from a performance point of view, whereas in case the transmitter, i.e. the transmitting device 12, is less stable transmitting signals with lower quality, the receiving device 10 may have to use some more robust mechanism, at least partly based on non-coherent combining. When the receiving device 10 does not know if the frequency error may be large, the receiving device 10 has to use the robust one since if in fact there is a large frequency error a less robust algorithm will not work. If it is so, however, that the signal is of high accuracy and with no frequency error it has been wasteful to use this robust mode. Methods for coherent and non-coherent combining are well known in the art, and so is when it is preferable to use the respective technique.

[00057] In some embodiments, this quality knowledge may be exploited in that if it is known that both the transmitting device 12 and the receiving device 10 are accurate, a more efficient synchronisation technique may be used and thereby a shorter syncword 61 may be used resulting in reduced overhead. In case the transmitting device 12 is accurate, whereas the receiver is not (or vice versa), a somewhat longer syncword 62, and finally, if both the transmitter and the receiver have low accuracy, e.g. only fulfilling the minimum requirements from specification, an even longer syncword 63 may be used. This embodiment is illustrated in Figure 5. In this fig. 6 also the length of the header is changed based on the accuracy of the transmitter and the receiver. A short header 64 may be used if both the transmitting device 12 and the receiving device 10 has high accuracy, i.e. high quality of the transmitting device 12 and the receiving device 10. A normal header 65 may be used if one of the transmitting device 12 and the receiving device 10 has high accuracy. And a long header 66 may be used if none of the transmitting device 12 and the receiving device 10 has high accuracy. This header change may or may not be used, but both cases are covered by this embodiment. The information about transmitting device 12 and the receiving device 10 accuracy, e.g., high or minimum accuracy or quality, may be stored and updated in a device memory, storing information about the paired devices. For example, if the transmitting device 12 has been successfully paired with receiving device 10 and learned about receiving device's transmission/reception, TX/RX accuracy, the transmitting device 12 can store this information along with other information it stores regarding to receiving device 10. Alternatively, respective address may be reserved for respective device meeting higher TX/RX accuracy requirements. In this case, a proper syncword may be selected dependent on a recipient address.

[00058] To ensure that proper reception is obtained may be to send known symbols embedded in the data to aid the receiving device 10. These known symbols are commonly known as pilot symbols, or just pilots. As these pilots are overhead and do not carry explicit information, it may be desirable to send as few of these as possible. On the other hand, a sufficient number of pilots may be needed in order to ensure that the data may be properly demodulated.
Typically, the more variations there are in the signal, either due to varying radio channel conditions or due to variations in the transmitting device 12 and the receiving device 10, the more dense the pilots need to be sent. Thus, a third property that may depend on the radio channel condition (SNR), also referred to as operating point, but in particular on the accuracy of the transmitting device 12 and the receiving device 10, is how much pilots are used in the transmission, e.g. how many data symbols are transmitted between two pilots.

[00059] This is illustrated in figure 7, where more pilots are used the lower the coding rate is, i.e., the lower the expected operating condition reflected as e.g.
the SNR at the receiving device 10. In the above embodiments, it has been assumed that the syncword and/or the coding for the header is made dependent on the coding rate used for the actual data in the way that given that the coding for the data is known, there is only one choice concerning what syncword to use and what coding for the header to use. In another embodiment, the receiving device 10 is determining how well the synchronisation works in relation to what is needed for the particular coding being used, and feeds back this information to the transmitting device 12. In this embodiment the suitable syncword may be based at least partly on feedback from the receiving device 10 to potentially further minimise the overhead. This feedback may either be explicit or implicit. In the explicit type of feedback, the receiving device 10 may signal specific information or index pointing out the syncword to use, e.g. if there are 8 different syncwords numbered between 0 up to 7 to select from, the receiving device 10 may signal a selection value of '3' as example. An example of implicit signalling is that the transmitting device 10 may receive acknowledgements on safe received data packages and may draw conclusion from that. In yet a further embodiment, the method how to utilise such implicit measurements to find the syncword or amount of pilots to use is disclosed. The method may be exemplified for illustration purpose by the following sequence of transmitting packets: the first packet is transmitted using a best performing, i.e.
longest, syncword; if the transmission is acknowledged a second packet is transmitted with a shorter syncword e.g. a second most reliable syncword; if this transmission is also acknowledged a third packet is transmitted with a yet shorter syncword e.g. a third most reliable syncword, etc. If the transmitting device reaches a shortest possible syncword and the transmitting device 12 keeps receiving acknowledgements on received packets, then no further reduction in the syncword length is done. On the other hand, when no acknowledgement is

60 PCT/SE2015/050152 received; then for example a last packet is re-transmitted with the same syncword as used at the failure; if this re-transmission also fails, i.e. no acknowledgment received, the transmitting device 12 may re-transmit the packet again with a next more robust, i.e. longer syncword, until acknowledgement is received. Alternatively, no repetition of the failed syncword length is done, and a length increase is done in the next re-transmission directly. Embodiments cover different starting selection of syncword as well different selections of syncwords in the iterative stages. Further the embodiments also cover the selection of the starting syncword both as random, according to some other criteria as received power level of packets from the receiving device 10 or as the transmitting device 12 has recorded and stored in memory a latest previous used syncword or related quality needed.
[00060] In an example, the transmitting device 12, also referred to as a first wireless device, and the receiving device 10, also referred to as a second wireless device, first make contact in order to become paired. As described above, many of these short range technologies are based on ad-hoc methods in order to get "connected" to each other. The transmitting device 12 and the receiving device may send and/or receive one or more messages exchanging different information about themselves. Once the two devices have some basic information about each other, they are said to be paired. The information they exchange may for example relate to capabilities they have. The procedures or methods for getting paired may be Bluetooth, Wi-Fi based, HomeRF, 802.11 technologies or similar.

[00061] When the transmitting device 12 wants to send a packet to receiving device 10, the packet may comprise, as described above, a syncword, a header and a data part. Figure 8 is a flowchart of an exemplifying embodiment of a method 800 performed by the transmitting device 12 for transmitting the packet to the receiving device 10. Firstly, the transmitting device 12 gets paired 810 with the receiving device 10. Then the transmitting device 12 determines 820 at least one of: the coding rate or modulation of the data, the coding rate of the header, the received signal quality, the quality of the transmitting device 12 and/or the receiving device 10, and feedback received from the receiving device 10 relating to a previous transmitted packet.

[00062] According to some embodiments herein, the transmitting device 12 may then generate or determine 830 a syncword to be included in the packet to be sent to the receiving device 10. The transmitting device 12 thus determines the syncword based on at least one of the coding rate or modulation of the data, the coding rate of the header, the received signal quality such as e.g. SNR or Signal to Noise and Interference Ratio (SINR) quality of the transmitting device 12 and/or the receiving device 10, and feedback received from the receiving device 10 relating to a previous transmitted packet. Determining the syncword may comprise determining the length of the syncword and/or the syncword itself.

[00063] The coding rate of the data and the coding rate of the header may be known to the transmitting device 12, since it is the transmitting device 12 that determines the respective coding rate. The received signal quality may be obtained in different ways. For example, the transmitting device 12 may measure the received signal quality of signals received from the receiving device 10, either when receiving data packets transmitted from the receiving device 10 or during the procedure for getting paired when the transmitting device 12 and the receiving device 10 transmit and receive various signals for exchanging information. The transmitting device 12 may alternatively receive a measurement report from the receiving device 10 relating to the received signal quality of a previously transmitted packet and/or signal transmitted from the transmitting device 12.
The received signal quality may be mapped to a coding rate. For example, the received signal quality may be an estimate of SNR, and coding rate 1/2, i.e. repetition factor L = 2, may be chosen if the estimated SNR = 3 dB; coding rate 1/4, i.e.

repetition factor L = 4, may be chosen if the estimated SNR = 0 dB; coding rate 1/8, i.e. repetition factor L = 8, may be chosen if the estimated SNR = -3dB;
and coding rate 1/16, i.e. repetition factor L = 16, may be chosen if the estimated SNR = -6 dB.

[00064] Information relating to the quality or accuracy of the transmitting device 12 and the receiving device 10 may be exchanged between the devices at some point, for example during the procedure to become paired. Thus, the transmitting device 12 has knowledge of the quality of the receiving device 10 as well as its own quality.

[00065] Also as described above, the receiving device 10 may send acknowledgements of received transmissions which may indicate either just received or may alternatively also comprise information about e.g. received signal quality or any other information that the transmitting device 12 may use to deduce that the syncword of the previous transmission was just enough or possible too long.

[00066] The transmitting device 12 may further determine a density of pilot symbols to use in the packet to be sent to the receiving device 10. The transmitting device 12 may determine the density, i.e. how many pilot symbols to insert in the packet, based on e.g. the received signal quality and/or the quality of the transmitting device 12 and/or the receiving device 10.

[00067] An advantage with the proposed methods and apparatuses is that embodiments herein may minimise the overhead that is needed in a packet based system where more than one fixed packet type, data rate and/or operational condition are used. Embodiments herein may also allow for decreased overhead in case the transmitter, the receiver, or both transmitter and receiver are implemented with a better quality i.e. accuracy and performance than minimum required by the specification. A reduced overhead may directly translate into improved power efficiency, increased battery life, reduced interference to other devices, and smaller probability of being interfered by other devices. This in its turn leads to an improved performance of the wireless communication network 1.

[00068] By some embodiments and examples described above, a transmitting device 12 is provided where at least one of the synchronisation word and the modulation and coding used for the header of a packet may at least in part be selected based on what coding and modulation is used for the data part of the packet.

[00069] A longer synchronisation word may be used the more robust coding and/or modulation is used for the data part of the packet.

[00070] A more robust coding scheme for the header may be selected when a more robust coding scheme is used for the data.

[00071] A transmitting device 12 and a communication system are disclosed where there are more than one possible syncword and where the selected syncword to be used may at least partly be based on the accuracy of at least one of the transmitting device 12 and the receiving device 10.

[00072] A transmitting device 12 and a communication system are disclosed using pilots embedded in the data part of the signal, wherein the fraction of pilots relative to the data is dependent on what modulation and coding is used for the data.

[00073] A transmitting device 12 and a communication system are disclosed using pilots embedded in the data part of the signal/packet, wherein the fraction of pilots relative to the data may be dependent on the accuracy of at least one of the transmitting wireless device and the receiving wireless device.

[00074] A transmitting device 12 and a communication system are disclosed, where a higher fraction of pilots may be used the less accurately the at least one of the transmitting wireless device and receiving wireless device is.

[00075] A transmitting device 12 and a communication system are disclosed, where more than one syncword may be used, and where the longer syncwords are constructed by repeating one of the shorter syncwords an integer number of times.

[00076] An iterative method to implicitly find the syncword to use is disclosed herein.

[00077] A method performed by a transmitting device 12 is disclosed for selecting the starting syncword to use.

[00078] Fig. 9 is a block diagram of the transmitting device 12 adapted to perform the methods described above for transmitting a packet to the receiving device in the wireless communication network 1. The transmitting device 12 is configured to determine one or more of: a radio channel condition of a channel between the transmitting device 12 and the receiving device 10, a coding rate or modulation of the packet, a coding rate of a header of the packet, and a quality of the transmitting device 12 and/or the receiving device 10.

[00079] The transmitting device 12 is configured to determine a packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10.

[00080] The transmitting device 12 is further configured to transmit data with the determined packet structure to the receiving device 10.

[00081] The transmitting device 12 may further be configured to determine the radio channel condition based on at least one of: a received signal quality at the receiving device 10, and a feedback received from the receiving device 10 relating to a previously transmitted packet.

[00082] The transmitting device 12 may further be configured to determine packet structure by determining a synchronisation word in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10.

[00083] The transmitting device 12 may further be configured to determine packet structure by determining a shorter synchronisation word when a higher coding rate is used for data than a synchronisation word when a lower coding rate is used for data.

[00084] The transmitting device 12 may further be configured to construct the synchronisation word by repeating one shorter synchronisation word an integer number of times.

[00085] The transmitting device 12 may be configured to determine packet structure by determining a density of pilot signals in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10.

[00086] The transmitting device 12 may be configured to determine packet structure by changing a coding or modulation for the header in the packet structure based on a coding or modulation used for a user data.

[00087] The transmitting device 12 may be configured to determine packet structure by changing length of a header in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10.

[00088] The transmitting device 12 may further be configured to pair the transmitting device 12 with the receiving device 10.

[00089] The transmitting device 12 may further be configured to determine the packet structure to minimize overhead in the packet structure.

[00090] The transmitting device 12 may comprise a processor 921 and memory 922, wherein the memory 922 comprises instructions which when executed by the processor 921 causes the transmitting device 12 to perform the methods described above.

[00091] Figure 9 also illustrates the transmitting device 12 comprising a memory 910. It shall be pointed out that figure 9 is merely an exemplifying illustration and memory 910 may be optional, be a part of the memory 922 or be a further memory of the transmitting device 12. The memory may for example comprise information relating to the transmitting device 12, to statistics of operation of the transmitting device 12, just to give a couple of illustrating examples. In another example, the memory 910 comprises information relating to the receiving device, e.g.
obtained during the pairing of the transmitting and the receiving device. Figure 9 further illustrates the transmitting device 12 comprising processing means 920, which comprises the memory 922 and the processor 921. Still further, figure 9 illustrates the transmitting device 12 comprising a communication unit 930. The communication unit 930 may comprise an interface through which the transmitting device 12 communicates with other nodes or entities of the wireless communication network as well as wireless device and the receiving device 10 of the wireless communication network 1. Figure 9 also illustrates the transmitting device 12 comprising further functionality 940. The further functionality 940 may comprise hardware of software necessary for the transmitting device 12 to perform different tasks that are not disclosed herein.

[00092] Figure 10 is a block diagram of the transmitting device 12 for performing the methods described above. The transmitting device 900 is an example and illustrated comprising a receiving unit 1003 for receiving transmissions and signals from other nodes and devices, e.g. receiving device 10 during pairing.
The transmitting device 12 is also illustrated comprising a pairing unit 1004 for performing actions relating to the pairing process with another device, e.g.
the receiving device 10. Further, the transmitting device 12 is illustrated comprising a determining unit 1005 for determining e.g. the syncword as described above and a transmitting unit 1006 for transmitting the packet to another node or device, e.g. receiving device 10.

[00093] The processing means 920 and/or the determining unit 1005 may be configured to determine one or more of: a radio channel condition of a channel between the transmitting device 12 and the receiving device 10, a coding rate or modulation of the packet, a coding rate of a header of the packet, and a quality of the transmitting device 12 and/or the receiving device 10.

[00094] The processing means 920 and/or the determining unit 1005 may be configured to determine a packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10.

[00095] The processing means 920 and/or the transmitting unit 1006 may be configured to transmit data with the determined packet structure to the receiving device 10.

[00096] The processing means 920 and/or the determining unit 1005 may be configured to determine the radio channel condition based on at least one of:
a received signal quality at the receiving device 10, and a feedback received from the receiving device 10 relating to a previously transmitted packet.

[00097] The processing means 920 and/or the determining unit 1005 may be configured to determine packet structure by determining a synchronisation word in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10.

[00098] The processing means 920 and/or the determining unit 1005 may be configured to determine packet structure by determining a shorter synchronisation word when a higher coding rate is used for data than a synchronisation word when a lower coding rate is used for data.

[00099] The processing means 920 and/or the determining unit 1005 may be configured to construct the synchronisation word by repeating one shorter synchronisation word an integer number of times.

[000100] The processing means 920 and/or the determining unit 1005 may be configured to determine packet structure by determining a density of pilot signals in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10.

[000101] The processing means 920 and/or the determining unit 1005 may be configured to determine packet structure by changing a coding or modulation for the header in the packet structure based on a coding or modulation used for a user data.

[000102] The processing means 920 and/or the determining unit 1005 may be configured to determine packet structure by changing length of a header in the packet structure based on the determined radio channel condition, the determined coding rate of the packet, the determined coding rate or modulation of the header of the packet, and/or the determined quality of the transmitting device 12 and/or the receiving device 10.

[000103] The processing means 920 and/or the pairing unit 1004 may be configured to pair the transmitting device 12 with the receiving device 10.

[000104] The processing means 920 and/or the determining unit 1005 may be configured to determine the packet structure to minimize overhead in the packet structure.

[000105] In Fig. 10, the transmitting device 12 is also illustrated comprising a communication unit 1001. Through this communication unit 1001, the transmitting device 12 is adapted to communicate with other nodes and/or entities in the wireless communication network 1. The communication unit 1001 may comprise more than one receiving arrangement. For example, the communication unit 1001 may be connected to both a wire and an antenna, by means of which the transmitting device 12 enabled to communicate with other nodes and/or entities and devices in the wireless communication network. Similarly, the communication unit 1001 may comprise more than one transmitting arrangement, which in turn may be connected to both a wire and an antenna, by means of which the transmitting device 12 is enabled to communicate with other nodes and/or entities and devices in the wireless communication network. The transmitting device 12further comprises a memory 1002 for storing data. Further, the transmitting device 12 may comprise a control or processing unit (not shown) which in turn is connected to the different units 1003-1006. It shall be pointed out that this is merely an illustrative example and the transmitting device 12 may comprise more, less or other units or modules which execute the functions of the transmitting device 12 in the same manner as the units illustrated in Fig. 10.

[000106] It should be noted that Fig. 10 merely illustrates various functional units in the transmitting device 12 in a logical sense. The functions in practice may be implemented using any suitable software and hardware means/circuits etc. Thus, the embodiments are generally not limited to the shown structures of the transmitting device 12 and the functional units. Hence, the previously described exemplary embodiments may be realised in many ways. For example, one embodiment includes a computer-readable medium having instructions stored thereon that are executable by the control or processing unit for executing the method steps in the transmitting device 12. The instructions executable by the computing system and stored on the computer-readable medium perform the method steps of the transmitting device 12 as described above.

[000107] Fig. 11 schematically shows an embodiment of an arrangement in the transmitting device 12. Comprised in the arrangement in the transmitting device 12 are here a processing unit 1106, e.g. with a Digital Signal Processor, DSP.
The processing unit 1006 may be a single unit or a plurality of units to perform different actions of procedures described herein. The transmitting device 12 may also comprise an input unit 1102 for receiving signals from other entities, and an output unit 1104 for providing signal(s) to other entities. The input unit 1102 and the output unit 1104 may be arranged as an integrated entity or as illustrated in the example of figure 10, as one or more interfaces or communication units 1001.

[000108] Furthermore, the arrangement in the transmitting device 12 comprises at least one computer program product 1108 in the form of a non-volatile memory, e.g. an Electrically Erasable Programmable Read-Only Memory (EEPROM), a flash memory and a hard drive. The computer program product 1108 comprises a computer program 1110, which comprises code means, which when executed in the processing unit 1106 in the arrangement in the transmitting device 12 causes the transmitting device 12 to perform the actions e.g. of the procedure described earlier, for example as in Fig. 2.

[000109] The computer program 1110 may be configured as a computer program code structured in computer program modules 1110a-1110e. Hence, in an exemplifying embodiment, the code means in the computer program of the transmitting device 12 comprises a receiving unit, or module, for receiving transmissions and signals from other nodes and devices, e.g. receiving device.

The computer program further comprises a pairing unit, or module, for performing actions relating to the pairing process with another device, e.g. receiving device 10. Further, the computer program comprises a determining unit, or module, for determining the syncword as described above and a transmitting unit, or module, for transmitting the packet to another node or device, e.g. receiving device 10.

[000110] The computer program modules could essentially perform the actions described above, or of the flow illustrated in Fig. 2, to emulate the transmitting device 12. In other words, when the different computer program modules are executed in the processing unit 1106, they may correspond to the units 1003-of Fig. 10.

[000111] Although the code means in the embodiments and examples disclosed above may be implemented as computer program modules which when executed in the processing unit causes the transmitting device to perform the actions described above, at least one of the code means may in alternative embodiments be implemented at least partly as hardware circuits.

[000112] The processor may be a single Central Processing Unit, CPU, but could also comprise two or more processing units. For example, the processor may include general purpose microprocessors; instruction set processors and/or related chips sets and/or special purpose microprocessors such as Application Specific Integrated Circuits, ASICs. The processor may also comprise board memory for caching purposes. The computer program may be carried by a computer program product connected to the processor. The computer program product may comprise a computer readable medium on which the computer program is stored. For example, the computer program product may be a flash memory, a Random-Access Memory RAM, Read-Only Memory, ROM, or an EEPROM, and the computer program modules described above could in alternative embodiments be distributed on different computer program products in the form of memories within the transmitting device.

[000113] It is to be understood that the choice of interacting units, as well as the naming of the units within this disclosure are only for exemplifying purpose, and nodes suitable to execute any of the methods described above may be configured in a plurality of alternative ways in order to be able to execute the suggested procedure actions.

[000114] It should also be noted that the units described in this disclosure are to be regarded as logical entities and not with necessity as separate physical entities.

[000115] Fig. 12 is a block diagram depicting the receiving device 10 for receiving a packet from a transmitting device 12 in a wireless communication network 1.
The receiving device 10 is configured to receive a packet with a packet structure from the transmitting device 12.

[000116] The receiving device 10 is further configured to transmit, to the transmitting device 12, at least one of: a received signal quality at the receiving device 10, a quality of the receiving device 10, and a feedback relating to the previously received packet associated with a radio channel condition of a channel between the receiving device 10 and the transmitting device 12.

[000117] The receiving device 10 is further configured to receive data in an adjusted packet structure from the transmitting device 12, the adjusted packet structure being based on the radio channel condition and/or a quality of the transmitting device 12 and/or the receiving device 10.

[000118] The receiving device 10 may further be configured to pair the receiving device 10 with the transmitting device 12.

[000119] For example, the receiving device 10 may comprise processing means 1201. The receiving device may comprise a receiving module 1202. The processing means 1201 and/or the receiving module 1202 may be configured to receive the packet with a packet structure from the transmitting device 12.
The processing means 1201 and/or the receiving module 1202 may further be configured to receive data in an adjusted packet structure from the transmitting device 12, the adjusted packet structure being based on the radio channel condition and/or a quality of the transmitting device 12 and/or the receiving device 10.

[000120] The receiving device may comprise a transmitting module 1203. The processing means 1201 and/or the transmitting module 1203 may be configured to transmit, to the transmitting device 12, at least one of: a received signal quality at the receiving device 10, a quality of the receiving device 10, and a feedback relating to the previously received packet associated with a radio channel condition of a channel between the receiving device 10 and the transmitting device 12.

[000121] The receiving device may comprise a pairing module 1204. The processing means 1201 and/or the pairing module 1204 may be configured to pair the receiving device 10 with the transmitting device 12.

[000122] The methods according to the embodiments described herein for the receiving device 10 are respectively implemented by means of e.g. a computer program 1205 or a computer program product, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the receiving device 10. The computer program 1205 may be stored on a computer-readable storage medium 1206, e.g. a disc or similar. The computer-readable storage medium 1206, having stored thereon the computer program, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the receiving device 10. In some embodiments, the computer-readable storage medium may be a non-transitory computer-readable storage medium.

[000123] As will be readily understood by those familiar with communications design, that functions means or modules may be implemented using digital logic and/or one or more microcontrollers, microprocessors, or other digital hardware.
In some embodiments, several or all of the various functions may be implemented together, such as in a single application-specific integrated circuit (ASIC), or in two or more separate devices with appropriate hardware and/or software interfaces between them. Several of the functions may be implemented on a processor shared with other functional components of a wireless device or network node, for example.

[000124] Alternatively, several of the functional elements of the processing means discussed may be provided through the use of dedicated hardware, while others are provided with hardware for executing software, in association with the appropriate software or firmware. Thus, the term "processor" or "controller"
as used herein does not exclusively refer to hardware capable of executing software and may implicitly include, without limitation, digital signal processor (DSP) hardware, read-only memory (ROM) for storing software, random-access memory for storing software and/or program or application data, and non-volatile memory.
Other hardware, conventional and/or custom, may also be included. Designers of communications receivers will appreciate the cost, performance, and maintenance tradeoffs inherent in these design choices.

[000125] According to an aspect a method performed by a transmitting device for transmitting a packet to a receiving device is provided in some embodiments.
The method may comprise pairing itself with the receiving device; and determining at least one of coding rate of the data, coding rate of the header, received signal quality, quality of the transmitting device and/or the receiving device, and feedback received from the receiving device relating to a previous transmitted packet.
The method may further comprise determining a syncword (synchronisation word) based on at least one of coding rate of the data, coding rate of the header, received signal quality, quality of the transmitting device and/or the receiving device, and feedback received from the receiving device relating to a previous transmitted packet.

[000126] According to an aspect, a transmitting device adapted for transmitting a packet to a receiving device is provided in some embodiments. The transmitting device may be configured to pair itself with the receiving device; and to determine at least one of coding rate of the data, coding rate of the header, received signal quality, quality of the transmitting device and/or the receiving device, and feedback received from the receiving device relating to a previous transmitted packet.
The transmitting device may further be configured to determine a syncword based on at least one of coding rate of the data, coding rate of the header, received signal quality, quality of the transmitting device and/or the receiving device, and feedback received from the receiving device relating to a previous transmitted packet.

[000127] It will be appreciated that the foregoing description and the accompanying drawings represent non-limiting examples of the methods and apparatus taught herein. As such, the inventive apparatus and techniques taught herein are not limited by the foregoing description and accompanying drawings.

Instead, the embodiments herein are limited only by the following claims and their legal equivalents.

Claims

34

1. A method performed by a transmitting device (12) for transmitting a packet to a receiving device in a wireless communication network, comprising - determining (202) one or more of: a radio channel condition of a channel between the transmitting device (12) and the receiving device (10), a coding rate or modulation of the packet, a coding rate of a header of the packet, and a quality of the transmitting device (12) and/or the receiving device (10);
- determining (203) a packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device (12) and/or the receiving device (10); and - transmitting (204) data with the determined packet structure to the receiving device (10).

2. A method according to claim 1, wherein the determining (202) the radio channel condition is based on at least one of: a received signal quality at the receiving device (10), and a feedback received from the receiving device (10) relating to a previously transmitted packet.

3. A method according to any of the claims 1-2, wherein the determining (203) the packet structure comprises determining a synchronisation word in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device (12) and/or the receiving device (10).

4. A method according to any of the claims 1-3, wherein the determining (203) the packet structure comprises determining a shorter synchronisation word when a higher coding rate is used for data than a synchronisation word when a lower coding rate is used for data.

5. A method according to any of the claims 3-4, wherein the synchronisation word is constructed by repeating one shorter synchronisation word an integer number of times.

6. A method according to any of the claims 1-5, wherein the determining (203) the packet structure comprises determining a density of pilot signals in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device (12) and/or the receiving device (10).

7. A method according to any of the claims 1-6, wherein the determining (203) the packet structure comprises changing a coding or modulation for the header in the packet structure based on a coding or modulation used for a user data.

8. A method according to any of the claims 1-7, wherein the determining (203) the packet structure comprises changing length of a header in the packet structure based on the determined radio channel condition, the determined coding rate of the packet, the determined coding rate or modulation of the header of the packet, and/or the determined quality of the transmitting device (12) and/or the receiving device (10).

9. A method according to any of the claims 1-8, further comprising - pairing (201) the transmitting device (12) with the receiving device (10).

10.A method according to any of the claims 1-9, wherein the determining (203) the packet structure is to minimize overhead in the packet structure.

11.A method performed by a receiving device (10) for receiving a packet from a transmitting device (12) in a wireless communication network (1), the method comprising:
- receiving (212) a packet with a packet structure from the transmitting device (12);
- transmitting (213), to the transmitting device (12), at least one of: a received signal quality at the receiving device (10), a quality of the receiving device (10), and a feedback relating to the previously received packet associated with a radio channel condition of a channel between the receiving device (10) and the transmitting device (12); and - receiving (214) data in an adjusted packet structure from the transmitting device (12), the adjusted packet structure being based on the radio channel condition and/or a quality of the transmitting device (12) and/or the receiving device (10).

12.A method according to claim 11, further comprising - pairing (211) the receiving device (10) with the transmitting device (12).

13.A transmitting device (12) for transmitting a packet to a receiving device (10) in a wireless communication network; which transmitting device (12) is configured to:
determine one or more of: a radio channel condition of a channel between the transmitting device (12) and the receiving device (10), a coding rate or modulation of the packet, a coding rate of a header of the packet, and a quality of the transmitting device (12) and/or the receiving device (10);
determine a packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device (12) and/or the receiving device (10); and to transmit data with the determined packet structure to the receiving device (10).

14.A transmitting device (12) according to claim 13, configured to determine the radio channel condition based on at least one of: a received signal quality at the receiving device (10), and a feedback received from the receiving device (10) relating to a previously transmitted packet.

15.A transmitting device (12) according to any of the claims 13-14, configured to determine packet structure by determining a synchronisation word in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device (12) and/or the receiving device (10).

16.A transmitting device (12) according to any of the claims 13-15, configured to determine packet structure by determining a shorter synchronisation word when a higher coding rate is used for data than a synchronisation word when a lower coding rate is used for data.

17.A transmitting device (12) according to any of the claims 13-16, configured to construct the synchronisation word by repeating one shorter synchronisation word an integer number of times.

18.A transmitting device (12) according to any of the claims 13-17, configured to determine packet structure by determining a density of pilot signals in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device (12) and/or the receiving device (10).

19.A transmitting device (12) according to any of the claims 13-18 configured to determine packet structure by changing a coding or modulation for the header in the packet structure based on a coding or modulation used for a user data.

20.A transmitting device (12) according to any of the claims 13-19, configured to determine packet structure by changing length of a header in the packet structure based on the determined radio channel condition, the determined coding rate or modulation of the packet, the determined coding rate of the header of the packet, and/or the determined quality of the transmitting device (12) and/or the receiving device (10).

21.A transmitting device (12) according to any of the claims 13-20, further configured to pair the transmitting device (12) with the receiving device (10).

22.A transmitting device (12) according to any of the claims 13-21, further configured to determine the packet structure to minimize overhead in the packet structure.

23.A receiving device (10) for receiving a packet from a transmitting device (12) in a wireless communication network (1); the receiving device (10) being configured to:
receive a packet with a packet structure from the transmitting device (12);
transmit, to the transmitting device (12), at least one of: a received signal quality at the receiving device (10), a quality of the receiving device (10), and a feedback relating to the previously received packet associated with a radio channel condition of a channel between the receiving device (10) and the transmitting device (12); and receive data in an adjusted packet structure from the transmitting device (12), the adjusted packet structure being based on the radio channel condition and/or a quality of the transmitting device (12) and/or the receiving device (10).

24.A receiving device (10) according to claim 23, further being configured to pair the receiving device (10) with the transmitting device (12).