Methods and systems for wireless networks with relays

In an OFDM (orthogonal frequency division multiplexed) system, a method comprising:

• for two or more of a group consisting of:
• a base station (BS);
• at least one relay station (RS);
• and at least one mobile station (MS) of a plurality of MSs:
• using a same set of sub-carriers for downlink (DL) and/or uplink (UL) transmissions in a multiple hop network;
• and
• transmitting from a first MS to one of the BS and the at least one RS using a first sub-channel, wherein an antenna configuration of the first MS includes multiple antennas;
• and
• transmitting from a second MS to one of the BS and the at least one RS using a second sub-channel, wherein an antenna configuration of the second MS includes a single antenna, the transmissions from the first MS and the second MS occur simultaneously over different hops of the multiple hop network.

A method for inserting OFDM (orthogonal frequency division multiplexed) pilot symbols in a time-frequency resource in a system using relay stations (RSs), at least one RS having N transmitting antennas, where N>=1, comprising:

• inserting pilot symbols in time and frequency for each of the N transmitting antennas in a given relay station in symbol locations that are not assigned to pilot symbols used by a base station (BS) serving a cell in which the given RS is currently located or mobile stations (MSs) located in the cell served by the BS;
• and
• transmitting from a first MS to one of the BS and the given RS using a first sub-channel, wherein an antenna configuration of the first MS includes multiple antennas;
• and
• transmitting from a second MS to one of the BS and the given RS using a second sub-channel, wherein an antenna configuration of the second MS includes a single antenna, the transmissions from the first MS and the second MS occur simultaneously over different hops of the multiple hop network.