WO2013166728A1

WO2013166728A1 - Method and apparatus

Info

Publication number: WO2013166728A1
Application number: PCT/CN2012/075402
Authority: WO
Inventors: Li Zhang; Peter Skov
Original assignee: Nokia Siemens Networks Oy
Priority date: 2012-05-11
Filing date: 2012-05-11
Publication date: 2013-11-14

Abstract

A method comprises receiving a communication, said communication comprising a plurality of slots, wherein in a slot, a primary synchronisation signal is provided at one of a first and second symbol and a secondary synchronisation signal is provided in a downlink pilot time slot downlink.

Description

METHOD AND APPARATUS

This disclosure relates to a method and apparatus and in particular, but not exclusively in relation to primary and secondary synchronising signals. A wireless communication system can be seen as a facility that enables wireless carriers between two or more nodes such as fixed or mobile communication devices, access points such as base stations, servers and so on. A communication system and compatible communicating devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. For example, the standards, specifications and related protocols can define the manner how and what communication devices shall communicate, how various aspects of the communications shall be implemented and how the devices shall be configured. Examples of wireless systems include public /and mobile networks (PL N) such as cellular networks, satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). Wireless systems can be divided into coverage areas referred to as cells. Different types of cells can provide different features. For example, cells can have different shapes, sizes, power levels and other characteristics.

A user can access the communication system by means of an appropriate communication device. A communication device of a user is often referred to as user equipment (UE) or terminal. A communication device is provided with an appropriate signal receiving and transmitting arrangement for enabling communications with other parties. Wireless systems enable mobility for users where a mobile device can communicate over an air interface with another communication device such as e.g. a base station and/or other user equipment.

Examples of mobile communication systems are those based on standards by the 3rd Generation Partnership Project (3GPP). A recent 3GPP development is often referred to as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. The various development stages of the 3GPP LTE specifications are referred to as releases. In LTE base stations are commonly referred to as enhanced NodeBs (eNB).

LTE provides frequency division duplex (FDD) and time division duplex (TDD) modes for wireless communications. In LTE TDD physical layer the uplink and downlink are divided into 10 ms long radio frames. Figure 7 illustrates a radio frame structure 20 for LTE time division duplex (TDD). A LTE TDD radio frame is divided into timeslots where two consecutive slots form one subframe. Thus each frame can be understood as being divided into ten 1ms subframes #0 - #9.

According to an aspect, there is provided a method comprising: receiving a communication, said communication comprising a plurality of slots, wherein in a slot, a primary synchronisation signal is provided at one of a first and second symbol and a secondary synchronisation signal is provided in a downlink pilot time slot downlink.

The secondary synchronisation signal may be provided at the second symbol or the fourth symbol.

The communication may comprise a time division duplex communication.

The communication may comprise in a first of said slots a physical broadcast channel.

The communication may comprise at least one reference signal in at least one of a first of said slots and said second slot.

According to an aspect, there is provided a method comprising: receiving a communication, said communication comprising a plurality of slots, wherein in one of said slots, a primary synchronisation signal and a secondary synchronisation signal are separated by at least one symbol.

The primary synchronisation signal may be provided at a second symbol.

The secondary synchronisation signal may be provided at a fourth symbol.

The communication may comprise at least one reference signal in said slot.

The reference signals may be provided at one or more of the sixth, seventh, thirteenth and fourteenth symbols of said slot.

The plurality of slots may be provided in a subframe.

The slot may comprise one or more of the first and eleventh slot.

The communication may comprise a frequency division duplex communication. The method may comprise determining a position of at least one of said primary and secondary synchronising signals and in dependence on said determining, determining if said communication is a frequency division duplex transmission or a time division duplex transmission.

The method may determining a position of at least one of said primary and secondary synchronising signals and in dependence on said determining, determining a version of a standard associated with said communication.

According to an aspect, there is provided a method comprising: receiving a communication, said communication comprising a plurality of slots, wherein in a slot, a primary synchronisation signal and a secondary synchronisation signal are provided at first and second symbols.

According to an aspect, there is provided a method comprising: receiving a communication, said communication comprising a plurality of slots, wherein in a first of said slots, a primary synchronisation signal and a secondary synchronisation signal are provided at second and fourth symbols.

According to an aspect, there is provided a method comprising: providing a communication for transmission, said communication comprising a plurality of slots, wherein in a slot, a primary synchronisation signal is provided at one of a first and second symbol and a secondary synchronisation signal is provided in a downlink pilot time slot downlink.

The communication may comprise a time division duplex communication.

According to an aspect, there is provided a method comprising: providing for transmission a communication, said communication comprising a plurality of slots, wherein in one of said slots, a primary synchronisation signal and a secondary synchronisation signal are separated by at least one symbol.

The primary synchronisation signal may be provided at a second symbol.

The secondary synchronisation signal may be provided at a fourth symbol.

The communication may comprise at least one reference signal in said slot.

The plurality of slots may be provided in a subframe.

The slot may comprise one or more of the first and eleventh slot.

The communication may comprise a frequency division duplex communication.

According to an aspect, there is provided a method comprising: providing for transmission a communication, said communication comprising a plurality of slots, wherein in slot, a primary synchronisation signal and a secondary synchronisation signal are provided at first and second symbols. According to an aspect, there is provided a method comprising: providing for transmission a communication, said communication comprising a plurality of slots, wherein in a first of said slots, a primary synchronisation signal and a secondary synchronisation signal are provided at second and fourth symbols. An apparatus may be provided to perform any one or more of the methods outlined above. Means may be provided to perform one or more of the methods outlined previously.

An apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to perform one or more of the methods outlined previously may be provided.

A computer program comprising program code means adapted to perform the herein described methods may also be provided. In accordance with further embodiments apparatus and/or computer program product that can be embodied on a computer readable medium for providing at least one of the above methods is provided.

According to an aspect, there is provided an apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to; receive a communication, said communication comprising a plurality of slots, wherein in a slot, a primary synchronisation signal and a secondary synchronisation signal are provided at first and second symbols.

According to an aspect, there is provided an apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: receive a communication, said communication comprising a plurality of slots, wherein in a first of said slots, a primary synchronisation signal and a secondary synchronisation signal are provided at second and fourth symbols.

According to an aspect, there is provided an apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: provide for transmission a communication, said communication comprising a plurality of slots, wherein in a slot, a primary synchronisation signal and a secondary synchronisation signal are provided at first and second symbols.

According to an aspect, there is provided an apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: provide for transmission a communication, said communication comprising a plurality of slots, wherein in a first of said slots, a primary synchronisation signal and a secondary synchronisation signal are provided at second and fourth symbols. Embodiments may be used with uplink and/or downlink communication. The apparatus may be provided in a user equipment and/or base station.

According to an aspect, there is provided a signal comprising a plurality of slots, wherein in a first of said slots, a primary synchronisation signal and a secondary synchronisation signal are provided at second and fourth symbols. According to an aspect, there is provided a signal comprising a plurality of slots, wherein in a slot, a primary synchronisation signal and a secondary synchronisation signal are provided at first and second symbols.

It should be appreciated that any feature of any aspect may be combined with any other feature of any other aspect. Embodiments will now be described in further detail, by way of example only, with reference to the following examples and accompanying drawings, in which:

Figure 1 shows a schematic diagram of a communication system;

Figure 2 shows a schematic diagram of a user equipment;

Figure 3 shows a schematic diagram of a base station;

Figures 4a to c show a schematic view of the position of the primary synchronisation signal (PSS) and the secondary synchronisation signal (SSS) in some proposals;

Figure 5 shows a comparison between release 8 position for PSS/SSS and an embodiment, for TDD;

Figure 6 shows a comparison between release 8 position for PSS/SSS and an embodiment, for FDD; and

Figure 7 shows a radio frame. In the following certain exemplifying embodiments are explained with reference to a wireless or mobile communication system serving mobile communication devices. Before explaining in detail the exemplifying embodiments, certain general principles of wireless communications and radio link control are briefly explained with reference to Figures 1 to 3 to assist in understanding the technical detail underlying the described examples.

A non-limiting example of the recent developments in communication system architectures is the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) standardized by the 3rd Generation Partnership Project (3GPP). More recent development of the LTE, Release 10 and upwards, are sometimes referred to as LTE-Advanced. The LTE employs a mobile architecture known as the Evolved Universal Terrestrial Radio Access Network (E-UTRAN). Base stations of such systems are known as evolved or enhanced Node Bs (eNBs) and may provide E-UTRAN features such as user plane Radio Link Control/Medium Access Control/Physical layer protocol (RLC/MAC/PHY) and control plane Radio Resource Control (RRC) protocol terminations towards the communication devices. Other examples of radio access system include those provided by base stations of systems that are based on technologies such as wireless local area network (WLAN) and/or WiMax (Worldwide Interoperability for Microwave Access). Mobile communication devices 1 can be provided with wireless access via base stations or similar wireless transmitter and/or receiver nodes providing radio service areas or cells. Figure 1 shows two bases stations 2 and 4 proving eel! 3 and 5, respectively. A mobile communication device 1 may be located in the service areas of different cells, communicate with more than one cell and be handed over from a cell to another. The base station nodes can be connected to a core communications network via appropriate gateways and/or backhaul systems. It is noted that the base stations and mobile devices are only schematically shown for illustration purposes in Figure 1 , and that the number and type of these can vary considerably from that shown. Base stations are typically controlled by at least one appropriate control apparatus so as to enable operation thereof and management of mobile communication devices in communication with the base stations. The control apparatus can be interconnected with other control entities. The control apparatus can be configured to execute an appropriate software code to provide the control functions. The control apparatus and functions may be distributed between a plurality of control units. Two or more base stations may be controlled a control apparatus 6. A possible mobile device for communications with the base stations is often referred to as user equipment (UE) or terminal. A mobile device for implementing the embodiments may be provided by any device capable of sending radio signals to and/or receiving radio signals from multiple cells. Non-limiting examples include a mobile station (MS) such as a mobile phone or what is known as a 'smart phone', a portable computer provided with a wireless interface card or other wireless interface facility, personal data assistant (PDA) provided with wireless communication capabilities, or any combinations of these or the like. A mobile device may provide, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and so on. Users may thus be offered and provided numerous services via their devices. Non-limiting examples of these services include two-way or multi-way calls, data communication or multimedia services or simply an access to a data communications network system, such as the Internet. User may also be provided broadcast or multicast data. Non-limiting examples of the content include downloads, television and radio programs, videos, advertisements, various alerts and other information.

A mobile device may receive and transmit signals over an air interface via at least one appropriate transceiver apparatus. In Figure 2 transceiver apparatus of a mobile device 20 is designated schematically by block 26. The transceiver blocks 26 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

A mobile device is also provided with at least one data processing entity 21 , at least one memory 22, and other possible components 23 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The data processing, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 24.

The user may control the operation of the mobile device by means of a suitable user interface such as key pad 25, voice commands, touch sensitive screen or pad, combinations thereof or the like. A display 28, a speaker and a microphone can be also provided. Furthermore, a mobile communication device may comprise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories, for example hands-free equipment, thereto.

A wireless communication device, such as a base station and/or a mobile station, can be provided for example with two or more receivers facilitating receive diversity for enhanced aggregate receiver sensitivity, or a Multiple Input / Multiple Output (MIMO) antenna system for enabling multi-stream communications. Receiver (Rx) diversity and MIMO arrangements as such are known. Rx diversity uses multiple antennas at the receiver and MIMO systems use multiple antennas at the transmitter and receiver along with advanced digital signal processing to improve link quality and capacity. More data can be received and/or sent where there are more antenna elements.

Reference is made to Figure 3 which shows a base station 105. The base station comprises at least one memory 401 and at feast one data processing unit 402 and 403. The base station is provided with a first interface 404 for interfacing with the RNC or another controller. The base station is provided with a second interface 405 which is a wireless interface for interfacing with user equipment.

It should be appreciated that in the following the first slot, frame, symbol is numbered 0. Sequential numbering is used.

Figure 7 illustrates a radio frame structure 120 for LTE time division duplex (TDD). In LTE TDD physical layer the uplink and downlink are divided into 10 ms long radio frames. A LTE TDD radio frame is further divided into 0.5 ms timeslots, two consecutive slots forming one subframe. Thus each frame 120 is divided into ten 1ms subframes #0 - #9. Each frame can comprise at least one subframe 121 containing special fields known as downlink pilot time slot (DwPTS) 122, guard period (GP) 123 and uplink pilot time slot (UpPTS) 124. Such a subframe is commonly referred to as a special subframe. The special subframes of frame 20 are located at subframes #1 and #6 and are denoted by S, The special subframe has been defined e.g. for in LTE Release 8. The lengths of the individual fields 122, 123 and 124 in a special subframe can depend on the uplink/downlink configuration selected by the network. The total length of the three fields in a LTE special frame remains constant at 1 ms.

A cell search procedure in LTE may begin with a synchronisation procedure. This synchronisation procedure may use the primary synchronisation signal (PSS) and the secondary synchronisation signal (SSS). These signals are broadcast by a base station in each cell. By detecting these signals, a user equipment is able to obtain time and frequency synchronisation. These signals may also provide the user equipment with identity information associated with cell. Other information such as cyclic prefix length information may also be obtained. Once the user equipment has detected the synchronisation signals, the user equipment is able to decode the physical broadcast channel (the PBCH).

In more detail, the PSS detection allows the slots' timing to be determined as well as the physical layer ID. The SSS detection allows for the radio frame timing detection, cell ID detection and cyclic prefix length detection.

With this information, PBCH decoding is possible which provides system information required by the user equipment.

The PSS and SSS are broadcast or transmitted by the base station and therefore are down link signals.

In order for a UE or the like to perform coherent signal demodulation for signals received from a base station, the base station provides demodulation reference signals (DM-RS). The demodulation reference signals are user equipment specific reference signals and may be embedded in the data for specific user equipment. In some proposals for development of the LTE standard, it has been suggested that the position of the PSS and SSS signals may be changed. The signals may have a different frequency domain positions (that is different Physical resource blocks PRBs), different subframe level time domain positions (that is different from subframes 0 and 5) and/or different symbol level time domain positions (for example in FDD (frequency division duplex) using different symbols than the last two symbols of slot 0).

Some embodiments may avoid a collision between DM-RS and PSS/SSS.

In this regard, reference is made to figure 4a. Figure 4a shows the position of the PSS and SSS in release eight of the LTE standard. For FDD, PSS and SSS are mapped to the last two symbols- symbols 5 and 6 of slot 0. However, this position collides with DM-RS ports 7 to 14. These ports are also allocated the last two symbols of slot 0. Common reference signals for antenna port 0 are provided in the symbols 0 and 5, DM-RS is placed at the last two symbols in each slot as shown in Figure 4b, Rel-8 PSS/SSS is placed at the last two symbols of the slot#0 and slot#10.

Each reference pattern or signal may be transmitted from an antenna port at the base station. In some embodiments, the transmitted reference signal corresponding to a given antenna port defines the antenna port from the point of view of the user equipment and may enable the user equipment to obtain a channel estimate for data transmitted on that antenna port.

Antenna ports 7 to 8 may be user equipment specific reference signals for dual layer beam forming. These have been initially proposed in release nine. Antenna ports 9 to 14 are user equipment specific reference signals for multi-layered beam forming and first introduced in release 10.

In release 10, it has been suggested that transmission modes based on D -RS ports 7 to 4 are not used in physical resource blocks where the PSS and SSS are present. It has been proposed that only common reference signal based transmission modes can be used. Common reference signals are available to all user equipment in a cell and no user equipment specific processing is applied.

It has been suggested that common reference signals from antenna port 0 should not be used for demodulation. Some embodiments address the demodulation of the PDSCH (physical down link shared channel) in the physical resource blocks where the PSS and SSS present. In some embodiments, DM-RS based transmission modes may be used.

Figure 4b shows one proposal for the position of the PSS and SSS. As shown in figure 4b, the PSS and SSS are placed at symbols 2 and 3 (the first symbol being symbol 0) in slot 0. As can be seen, the DM-RS can be provided in the last two symbols of slot 0. In other words, symbols 5 and 6 of slot 0.

Figure 4c shows another proposal. In this proposal, the PSS and SSS are provided on symbol 1 of slot 0 and symbol 1 of slot 1. The DM-RS are again provided in the last two symbols of slot 0 and slot 1. However, currently, the PBCH (physical broadcast channel) is mapped, according to release 8 to the first four symbols of slot 1. According there is a conflict with the PBCH.

In some embodiments, the PSS and SSS positions for the TDD (time division duplex) mode are different to the PSS and SSS positions for the FDD mode. In some embodiments, the difference in the PSS and SSS positions for FDD and TDD may be used by the user equipment to distinguish the FDD mode from the TDD mode. In particular, the detection of the SSS allows a distinction to be made between the FDD and TDD mode. Reference is now made to figure 5 which shows a proposed PSS and SSS position for a TDD mode. Figure 5 shows on the left hand side the release 8 configuration and on the right hand side an embodiment. The five slots shown are a half frame.

In the embodiment, the position of the DwPTS is retained and is as discussed in relation to Figure 7. The DwPTS is at least 3 symbols. In the embodiment, time slot 1 in the frame should contain DwPTS. This is pilot information for the down link. The DM-RS in the DwPTS is placed in symbols 2 and 3 of slot 1. As the minimum length of DwPTS is three OFDM symbols, the PSS should be placed at symbol 0 or symbol 1. In the embodiment shown in Figure 5, the PSS is at symbol 0. Further the SSS is also included in the DwPTS. In the embodiment, the SSS is provided at symbol 1.

In another embodiment, the PSS may be at symbol 1 and the SSS symbol 4.

In slot 0, the DM-RS is provided at symbols 5 and 6. The PBCH is provided at symbols 7, 8, 9 and 10. Symbols 12 and 13 provide the DM-RS.

Reference is made to the release 8 configuration on the left of Figure 5. In slot 0, symbols 7, 8, 9 and 10 are used by the PBCH. The last symbol, symbol 13, is used for the SSS. In slot 1 , the PSS is at the third symbol. In Rel 8, DwPTS is the DL part of special subframe, which is the subframe#1 and subframe#6 in a radio frame in TDD. The number of OFDM symbols for DwPTS can vary with different configurations.

In the embodiment shown in figure 5, the CRS is assumed not be present in subframe 1. In some embodiments, the CRS port 0 may be truncated in the time domain. The CRS pattern, it is placed at symbol#0/4/7/11 in a subframe. As mentioned, there may be e.g. 6 symbols for DwPTS, and in such a case the CRS on symbol#7/11 may be truncated (or dropped).

In some embodiments the CRS port zero may be transmitted in the DwPTS. 4-port CRS will use symbol#1 , so it collides with the proposed PSS location. 1-port or 2-port CRS will not use symbol#1.

Figure 4 shows subframe#0, while in Figure 5 subframes #0 and subframes#1 are shown. In TDD subframe#1 is the "special" subframe, and the number of OFDM symbols for DwPTS can vary. Reference is now made to figure 6 which shows a proposed PSS and SSS position for a FDD mode. Figure 6 shows on the left hand side the release 8 configuration and on the right hand side an embodiment. The five slots shown are a half frame.

In the release 8 configuration, in slot 0, the SSS is at symbol 5. The PSS is at symbol 6. This is followed by the PBCH at symbols 7, 8, 9 and 10.

In the embodiment, in slot 0, the PSS is provided at symbol 1. At symbol 3, the SSS is provided. The D -RS are provided at symbols 5 and 6 as well as the as well as at symbols 12 and 13. The PBCH remains on symbols 7 to 10.

In some embodiments, the proposed PSS/SSS positions avoid collision with DM-RS symbols.

For FDD, PSS/SSS may be placed in the symbol#1 and symbol#3 of slot#0 and slot#10. Alternatively or additionally for TDD, PSS/SSS is placed in symbol#0 and symbo!#1 of s!ot#2 and slot#12.

CRS is transmitted in subframe#0 and subframe#5 for both FDD and TDD. DM-RS may be as defined in Rel-10.

In this disclosure the index of the first subframe, slot etc is 0.

In LTE a radio frame consists of 10 subframes, SF#0 to SF#9. There are 2slots within a subframe, so 20 slots in the radio frame, slot#0 to

slot#19. There are 7 OFDM symbols per slot, symbol#0 to symbol#6. For

TDD, SF#1 and SF#6 are special subframe consisting DwPTS, Guard Period

and UpPTS, and DwPTS can occupy 3 to 9 OFDM symbols depending on the configuration.

"slot#2" is the same as "the first slot of subframe#1 ". Subframe 0 has slot 0 and 1 and subframe 1 has slot 2 and 3. In TDD, the PSS/SSS may be placed in symbol 0 and 1 of slot 2 (of subframe 1) and slot 2.

As can be seen, the position of the PSS and SSS are different enabling the UE to differentiate between FDD and TDD based on the different positions of the PSS and SSS. The determining may alternatively or additionally allow a determination as to a version of a standard being used. It is noted that whilst embodiments have been described using LTE and LTE Advanced as examples, similar principles can be applied to any other communication system or indeed to further developments with LTE where TDD is employed. Thus, instead of LTE, the invention may be applied to other cellular standards as well. Also, instead of carriers provided by base stations at least one of the carriers may be provided by a communication device such as mobile user equipment. For example, this may be the case in application where no fixed equipment provided but a communication system is provided by means of a plurality of user equipment, for example in adhoc networks. Therefore, although certain embodiments were described above by way of example with reference to certain exemplifying architectures for wireless networks, technologies and standards, embodiments may be applied to any other suitable forms of communication systems than those illustrated and described herein.

The required data processing apparatus and functions of a base station apparatus, a communication device and any other appropriate apparatus may be provided by means of one or more data processors. The described functions at each end may be provided by separate processors or by an integrated processor. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi core processor architecture, as non- limiting examples. The data processing may be distributed across several data processing modules. A data processor may be provided by means of, for example, at least one chip. Appropriate memory capacity can also be provided in the relevant devices. The memory or memories may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory.

In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects of the invention may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.

The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the spirit and scope of this invention as defined in the appended claims. Indeed there is a further embodiment comprising a combination of one or more of any of the other embodiments previously discussed.

Claims

What is claimed is:

1. A method comprising:

receiving a communication, said communication comprising a plurality of slots, wherein in a slot, a primary synchronisation signal is provided at one of a first and second symbol and a secondary synchronisation signal is provided in a downlink pilot time slot downlink.

2. A method as claimed in claim 1 , wherein said secondary synchronisation signal is provided at the second symbol or the fourth symbol.

3. A method as claimed in claim 1 or 2, wherein said communication comprises a time division duplex communication.

4. A method as claimed in any preceding claim, wherein said communication comprises in a first of said slots a physical broadcast channel.

5. A method as claimed in any preceding claim, wherein said slot comprises a first slot of a second subframe.

6. A method comprising:

receiving a communication, said communication comprising a plurality of slots, wherein in one of said slots, a primary synchronisation signal and a secondary synchronisation signal are separated by at least one symbol.

7. A method as claimed in claim 6, wherein said primary synchronisation signal is provided at a second symbol.

8. A method as claimed in claim 6 or 7, wherein said secondary synchronisation signal is provided at a fourth symbol.

9. A method as claimed in any preceding claim, wherein said communication comprises at least one reference signal in said slot.

10. A method as claimed in claim 9, wherein said reference signals are provided at one or more of the sixth, seventh, thirteenth and fourteenth symbols of said slot.

11. A method as claimed in any of claims 6 to 10, when appended to claim 6, wherein said slot comprises one or more of the first and eleventh slot.

12. A method as claimed in any of claims 6 to 11 , when appended to claim 6, wherein said communication comprises a frequency division duplex communication

13. A method as claimed in any preceding claim, wherein said plurality of slots are provided in a subframe.

14. A method as claimed in any preceding claim, comprising determining a position of at least one of said primary and secondary synchronising signals and in dependence on said determining, determining if said communication is a frequency division duplex transmission or a time division duplex transmission.

15. A method as claimed in any preceding claim, comprising determining a position of at least one of said primary and secondary synchronising signals and in dependence on said determining, determining a version of a standard associated with said communication.

16. A method comprising: receiving a communication, said communication comprising a plurality of slots, wherein in a slot, a primary synchronisation signal and a secondary synchronisation signal are provided at first and second symbols.

17. A method comprising: receiving a communication, said communication comprising a plurality of slots, wherein in a first of said slots, a primary synchronisation signal and a secondary synchronisation signal are provided at second and fourth symbols.

18. A method comprising: providing for transmission a communication, said communication comprising a plurality of slots, wherein in a slot, a primary synchronisation signal and a secondary synchronisation signal are provided at first and second symbols.

19. A method comprising: providing for transmission a communication, said communication comprising a plurality of slots, wherein in a first of said slots, a primary synchronisation signal and a secondary synchronisation signal are provided at second and fourth symbols.

20. An apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: receive a communication, said communication comprising a plurality of slots, wherein in a slot, a primary synchronisation signal and a secondary synchronisation signal are provided at first and second symbols.

21. An apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: receive a communication, said communication comprising a plurality of slots, wherein in a first of said slots, a primary synchronisation signal and a secondary synchronisation signal are provided at second and fourth symbols.

22. An apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: provide for transmission a communication, said communication comprising a plurality of slots, wherein in a slot, a primary synchronisation signal and a secondary synchronisation signal are provided at first and second symbols.

23. An apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: provide for transmission a communication, said communication comprising a plurality of slots, wherein in a first of said slots, a primary synchronisation signal and a secondary synchronisation signal are provided at second and fourth symbols.